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Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2018	Nov. 05, 2018
Document Information [Line Items]
Entity Registrant Name	Enstar Group LTD
Entity Central Index Key	0001363829
Trading Symbol	ESGR
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Voting Ordinary Shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		17,951,076
Non-Voting Convertible Ordinary Shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		3,509,682

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
ASSETS
Trading, at fair value	$ 6,545,280
Fixed maturities, available-for-sale, at fair value (amortized cost: 2018 — $163,696; 2017 — $208,097)	163,144	$ 210,285
Equities, trading, at fair value	130,314	106,603
Other investments, at fair value	2,036,430	913,392
Other investments, at cost	0	125,621
Total investments (Note 5 and Note 7)	8,875,168	7,232,185
Cash and cash equivalents	553,419	955,150
Restricted cash and cash equivalents	474,590	257,686
Funds held - directly managed (Note 6)	1,217,182	1,179,940
Premiums receivable	574,419	425,702
Deferred tax assets (Note 19)	13,782	13,001
Prepaid reinsurance premiums	191,669	245,101
Reinsurance balances recoverable (Note 9)	1,183,003	1,478,806
Reinsurance balances recoverable, at fair value (Note 7 and Note 9)	792,553	542,224
Funds held by reinsured companies	254,029	175,383
Deferred acquisition costs	125,132	64,984
Goodwill and intangible assets (Note 13)	219,295	180,589
Other assets	646,987	831,320
Assets held for sale (Note 4)	0	24,351
TOTAL ASSETS	15,121,228	13,606,422
LIABILITIES
Losses and loss adjustment expenses (Note 10)	5,516,012	5,603,419
Losses and loss adjustment expenses, at fair value (Note 7 and Note 10)	3,019,721	1,794,669
Policy benefits for life and annuity contracts (Note 11)	107,466	117,207
Unearned premiums	743,024	583,197
Insurance and reinsurance balances payable	381,114	236,697
Deferred tax liabilities (Note 19)	14,942	15,262
Debt obligations (Note 14)	394,470	646,689
Other liabilities	570,474	972,457
Liabilities held for sale (Note 4)	0	11,271
TOTAL LIABILITIES	10,747,223	9,980,868
COMMITMENTS AND CONTINGENCIES (Note 21)
REDEEMABLE NONCONTROLLING INTEREST (Note 15)	458,328	479,606
SHAREHOLDERS’ EQUITY (Note 16)
Treasury shares, at cost	(421,559)	(421,559)
Additional paid-in capital	1,812,727	1,395,067
Accumulated other comprehensive income	9,170	10,468
Retained earnings	2,083,193	2,132,912
Total Enstar Group Limited Shareholders’ Equity	3,905,364	3,136,684
Noncontrolling interest	10,313	9,264
TOTAL SHAREHOLDERS’ EQUITY	3,915,677	3,145,948
TOTAL LIABILITIES, REDEEMABLE NONCONTROLLING INTEREST AND SHAREHOLDERS’ EQUITY	15,121,228	13,606,422
Voting Ordinary shares (issued and outstanding 2018: 17,934,107; 2017: 16,402,279)
SHAREHOLDERS’ EQUITY (Note 16)
Ordinary shares	17,934	16,402
Non-voting convertible ordinary Series C Shares (issued and outstanding 2018 and 2017: 2,599,672)
SHAREHOLDERS’ EQUITY (Note 16)
Ordinary shares	2,600	2,600
Non-voting convertible ordinary Series E Shares (issued and outstanding 2018: 910,010; 2017: 404,771)
SHAREHOLDERS’ EQUITY (Note 16)
Ordinary shares	910	405
Series C Preferred Shares (issued and held in treasury 2018 and 2017: 388,571)
SHAREHOLDERS’ EQUITY (Note 16)
Preferred Shares	389	389
Series D Preferred Shares (issued and outstanding 2018: 16,000)
SHAREHOLDERS’ EQUITY (Note 16)
Preferred Shares	400,000	0
Short-term Investments
ASSETS
Trading, at fair value	231,950	180,211
Fixed maturity investments
ASSETS
Trading, at fair value	6,313,330	5,696,073
Fixed maturities, available-for-sale, at fair value (amortized cost: 2018 — $163,696; 2017 — $208,097)	$ 163,144	$ 210,285

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Short-term investments, available-for-sale, at fair value, amortized cost	$ 163,696	$ 208,097
Ordinary shares, par value (in dollars per share)	$ 1	$ 1
Ordinary shares issued (in shares)	21,443,789	19,406,722
Ordinary shares outstanding (in shares)	21,443,789	19,406,722
Treasury shares at cost (in shares)	388,571	388,571
Voting Ordinary Shares
Ordinary shares issued (in shares)	17,934,107	16,402,279
Ordinary shares outstanding (in shares)	17,934,107	16,402,279
Series C Non-Voting Convertible Ordinary Shares
Ordinary shares issued (in shares)	2,599,672	2,599,672
Ordinary shares outstanding (in shares)	2,599,672	2,599,672
Series E Non-Voting Convertible Ordinary Shares
Ordinary shares issued (in shares)	910,010	404,771
Ordinary shares outstanding (in shares)	910,010	404,771
Series C Preferred Shares
Preferred shares issued (in shares)	388,571	388,571
Series D Preferred Stock
Preferred shares issued (in shares)	16,000	0
Preferred shares outstanding (in shares)	16,000	0
Fixed maturity investments
Short-term investments, available-for-sale, at fair value, amortized cost	$ 163,696	$ 208,097

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
INCOME
Net premiums earned	$ 264,597	$ 148,025	$ 663,628	$ 452,494
Fees and commission income	6,950	15,895	23,633	46,476
Net investment income	69,430	52,028	202,218	150,184
Net realized and unrealized gains (losses)	(57,223)	29,301	(254,671)	139,697
Other income (expenses)	11,543	(3,848)	34,477	19,206
Total income	295,297	241,401	669,285	808,057
EXPENSES
Net incurred losses and loss adjustment expenses	153,974	75,712	266,327	163,224
Life and annuity policy benefits	423	1,060	217	5,048
Acquisition costs	54,242	24,281	137,684	75,457
General and administrative expenses	102,553	100,325	300,425	309,283
Interest expense	4,640	6,410	21,573	20,851
Net foreign exchange losses	1,040	4,775	1,389	15,612
Loss on sale of subsidiary	0	6,740	0	16,349
Total expenses	316,872	219,303	727,615	605,824
EARNINGS (LOSS) BEFORE INCOME TAXES	(21,575)	22,098	(58,330)	202,233
INCOME TAXES	(746)	(1,432)	(4,564)	(3,234)
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	(22,321)	20,666	(62,894)	198,999
NET EARNINGS (LOSS) FROM DISCONTINUED OPERATIONS, NET OF INCOME TAXES	0	3,495	0	(1,005)
NET EARNINGS (LOSS)	(22,321)	24,161	(62,894)	197,994
Net loss (earnings) attributable to noncontrolling interest	11,489	14,832	19,096	(14,135)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	(10,832)	38,993	(43,798)	183,859
Dividends on preferred shares	(5,133)	0	(5,133)	0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$ (15,965)	$ 38,993	$ (48,931)	$ 183,859
Basic:
Net earnings (loss) from continuing operations (in dollars per share)	$ (0.74)	$ 1.83	$ (2.39)	$ 9.54
Net earnings (loss) from discontinued operations (in dollars per share)	0.00	0.18	0.00	(0.05)
Net earnings (loss) per ordinary share (in dollars per share)	(0.74)	2.01	(2.39)	9.49
Diluted:
Net earnings (loss) from continuing operations (in dollars per share)	(0.74)	1.81	(2.39)	9.47
Net earnings (loss) from discontinued operations (in dollars per share)	0.00	0.18	0.00	(0.05)
Net earnings (loss) per ordinary share (in dollars per share)	$ (0.74)	$ 1.99	$ (2.39)	$ 9.42
Weighted average ordinary shares outstanding:
Basic (in shares)	21,440,914	19,392,120	20,444,634	19,384,897
Diluted (in shares)	21,665,356	19,559,168	20,653,544	19,515,987

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
NET EARNINGS (LOSS)	$ (22,321)	$ 24,161	$ (62,894)	$ 197,994
Other comprehensive income, net of tax:
Unrealized holding gains (losses) on fixed income available-for-sale investments arising during the period	(1,310)	2,219	(3,007)	4,598
Reclassification adjustment for net realized gains (losses) included in net earnings	2	(3)	53	(254)
Unrealized gains (losses) arising during the period, net of reclassification adjustments	(1,308)	2,216	(2,954)	4,344
Change in currency translation adjustment	(143)	4,194	1,258	8,451
Reclassification to earnings on disposal of subsidiary	0	7,440	0	7,440
Total currency translation adjustment	(143)	11,634	1,258	15,891
Total other comprehensive income (loss)	(1,451)	13,850	(1,696)	20,235
Comprehensive income (loss)	(23,772)	38,011	(64,590)	218,229
Comprehensive (income) loss attributable to noncontrolling interest	11,505	14,432	19,494	(15,983)
COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	$ (12,267)	$ 52,443	$ (45,096)	$ 202,246

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Ordinary Shares Voting Ordinary Shares	Ordinary Shares Series C Non-Voting Convertible Ordinary Shares	Ordinary Shares Series E Non-Voting Convertible Ordinary Shares	Preferred Stock Series C Preferred Shares	Preferred Stock Series D Preferred Stock	Treasury Shares (Series C Preferred shares)	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Currency translation adjustment	Defined benefit pension liability	Unrealized gains (losses) on available-for-sale investments	Retained Earnings	Noncontrolling Interest (excludes Redeemable Noncontrolling Interest)
Balance, beginning of period at Dec. 31, 2016		$ 16,175	$ 2,792	$ 405		$ 0		$ 1,380,109	$ (23,549)	$ (18,993)		$ 88	$ 1,847,550	$ 8,520
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issue of shares		24		0		0		647
Conversion of shares		192	(192)
Issuance costs of Series D preferred shares								0
Amortization of share-based compensation								10,473
Change in other comprehensive income (loss)	$ 20,235									8,440		2,508
Reclassification to earnings on disposal of subsidiary										7,440
Net earnings (losses)													197,994	1,945
Net loss (earnings) attributable to noncontrolling interest	(14,135)												(14,135)
Dividend on preferred shares													0
Change in redemption of redeemable noncontrolling interests													760
Contribution of capital														22
Balance, end of period at Sep. 30, 2017		16,391	2,600	405	$ 389	0	$ (421,559)	1,391,229	(5,161)	(3,113)	$ (4,644)	2,596	2,037,051	10,487
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle													4,882
Balance, beginning of period at Dec. 31, 2017	3,145,948	16,402	2,600	405		0		1,395,067	10,468	11,171		2,440	2,132,912	9,264
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issue of shares		1,532		505		400,000		413,679
Conversion of shares		0	0
Issuance costs of Series D preferred shares								(10,781)
Amortization of share-based compensation								14,762
Change in other comprehensive income (loss)	(1,696)									1,270		(2,568)
Reclassification to earnings on disposal of subsidiary										0
Net earnings (losses)													(62,894)	1,000
Net loss (earnings) attributable to noncontrolling interest	19,096												19,096
Dividend on preferred shares													(5,133)
Change in redemption of redeemable noncontrolling interests													785
Contribution of capital														49
Balance, end of period at Sep. 30, 2018	$ 3,915,677	$ 17,934	$ 2,600	$ 910	$ 389	$ 400,000	$ (421,559)	$ 1,812,727	$ 9,170	$ 12,441	$ (3,143)	$ (128)	2,083,193	$ 10,313
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle													$ (1,573)

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
OPERATING ACTIVITIES:
Net earnings (loss)	$ (62,894)	$ 197,994
Net loss from discontinued operations	0	1,005
Adjustments to reconcile net earnings (losses) to cash flows used in operating activities:
Realized losses (gains) on sale of investments	15,794	(5,012)
Unrealized losses (gains) on investments	190,598	(108,011)
Depreciation and other amortization	25,276	28,925
Net change in trading securities held on behalf of policyholders	0	25,597
Sales and maturities of trading securities	3,380,333	4,111,406
Purchases of trading securities	(4,081,938)	(5,611,677)
Net loss on sale of subsidiary	0	16,349
Other non-cash items	12,978	10,544
Changes in:
Reinsurance balances recoverable	(305,434)	(628,654)
Funds held by reinsured companies	(115,888)	(206,985)
Losses and loss adjustment expenses	1,103,802	1,590,764
Policy benefits for life and annuity contracts	(5,928)	170
Insurance and reinsurance balances payable	144,805	(140,356)
Unearned premiums	159,827	20,330
Other operating assets and liabilities	(370,376)	215,365
Net cash flows provided by (used in) operating activities	90,955	(482,246)
INVESTING ACTIVITIES:
Acquisitions, net of cash acquired	2,317	(670)
Sale of subsidiary, net of cash sold	0	19,690
Sales and maturities of available-for-sale securities	48,889	60,202
Purchase of available-for-sale securities	(10,385)	(2,565)
Purchase of other investments	(784,316)	(98,203)
Redemption of other investments	340,298	202,581
Other investing activities	(8,155)	(16,831)
Net cash flows provided by (used in) investing activities	(411,352)	164,204
FINANCING ACTIVITIES:
Issuance of preferred shares, net of issuance costs	389,219	0
Dividends on preferred shares	(5,133)	0
Contribution by noncontrolling interest	49	22
Dividends paid to noncontrolling interest	0	(27,458)
Receipt of loans	441,022	534,100
Repayment of loans	(689,819)	(564,203)
Net cash flows provided by (used in) financing activities	135,338	(57,539)
EFFECT OF EXCHANGE RATE CHANGES ON FOREIGN CURRENCY CASH AND CASH EQUIVALENTS	232	6,292
NET DECREASE IN CASH AND CASH EQUIVALENTS	(184,827)	(369,289)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	1,212,836	1,318,645
CASH AND CASH EQUIVALENTS, END OF PERIOD	1,028,009	949,356
Supplemental Cash Flow Information:
Income taxes paid, net of refunds	16,268	11,107
Interest paid	24,618	18,043
Reconciliation to Consolidated Balance Sheets:
Cash, cash equivalents and restricted cash	$ 1,212,836	$ 1,318,645

Significant Accounting Policies

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

SIGNIFICANT ACCOUNTING POLICIES

1. SIGNIFICANT ACCOUNTING POLICIES

Basis of Preparation

These unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America ("U.S. GAAP") for interim financial information. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, these financial statements reflect all adjustments consisting of normal recurring items considered necessary for a fair presentation under U.S. GAAP. The results of operations for any interim period are not necessarily indicative of results of the full year. These financial statements should be read in conjunction with the consolidated financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2017. All significant inter-company transactions and balances have been eliminated. In these notes, the terms "we," "us," "our," or "the Company" refer to Enstar Group Limited and its consolidated subsidiaries. Certain prior period amounts have been reclassified to conform to the current period presentation. These reclassifications had no impact on net earnings.

Use of Estimates

The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Our actual results may differ materially from these estimates. Results of changes in estimates are reflected in earnings in the period in which the change is made. Accounting policies that we believe are most dependent on assumptions and estimates are considered to be our critical accounting policies and are related to the determination of:


•	liability for losses and loss adjustment expenses ("LAE");


•	liability for policy benefits for life contracts;


•	reinsurance balances recoverable;


•	gross and net premiums written and net premiums earned;


•	impairment charges, including other-than-temporary impairments on investment securities classified as available-for-sale, and impairments on goodwill, intangible assets and deferred charges;


•	fair value measurements of investments;


•	fair value estimates associated with accounting for acquisitions;


•	fair value estimates associated with loss portfolio transfer reinsurance agreements for which we have elected the fair value option; and


•	redeemable noncontrolling interests.

New Accounting Standards Adopted in 2018

Accounting Standards Update ("ASU") 2017-09, Stock Compensation - Scope of Modification Accounting

In May 2017, the Financial Accounting Standards Board ("FASB") issued ASU 2017-09, which amends the scope of modification accounting for share-based payment arrangements. The ASU provides guidance on the types of changes to the terms or conditions of share-based payment awards to which an entity would be required to apply modification accounting under Accounting Standards Codification ("ASC") 718 - Compensation - Stock Compensation. Specifically, an entity would not apply modification accounting if the fair value, vesting conditions, and classification of the awards are the same immediately before and after the modification. The adoption of this guidance did not have any impact on our consolidated financial statements and disclosures.

ASU 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost

In March 2017, the FASB issued ASU 2017-07, which amends the requirements in ASC 715 - Compensation - Retirement Benefits, related to the income statement presentation of the components of net periodic benefit cost for an entity’s sponsored defined benefit pension and other postretirement plans. The ASU requires entities to (1) disaggregate the current-service-cost component from the other components of net benefit cost (the “other components”) and present it with other current compensation costs for related employees in the statement of earnings, and (2) present the other components elsewhere in the statement of earnings and outside of income from operations if such a subtotal is presented. The ASU also requires entities to disclose the captions within the statement of earnings that contain the other components if they are not presented on appropriately described separate lines. In addition, only the service-cost component of the net benefit cost is eligible for capitalization, which is a change from prior practice, under which entities capitalize the aggregate net benefit cost when applicable. The adoption of this guidance did not have any impact on our consolidated financial statements and disclosures.

ASU 2017-05, Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets

In February 2017, the FASB issued ASU 2017-05, which clarifies the scope of the Board’s guidance on nonfinancial asset derecognition (ASC 610-20) as well as the accounting for partial sales of nonfinancial assets. The ASU conforms the derecognition on nonfinancial assets with the model for transactions in the new revenue standard (ASC 606, as amended). The ASU clarifies that ASC 610-20 applies to the derecognition of all nonfinancial assets and in-substance nonfinancial assets. The ASU also requires an entity to derecognize the nonfinancial asset or in-substance nonfinancial asset in a partial sale transaction when (1) the entity ceases to have a controlling financial interest in a subsidiary pursuant to ASC 810, and (2) control of the asset is transferred in accordance with ASC 606. The adoption of this guidance did not have any impact on our consolidated financial statements and disclosures.

ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory

In October 2016, the FASB issued ASU 2016-16, which requires immediate recognition of the tax consequences of many intercompany asset transfers other than inventory. The adoption of this guidance did not have a material impact on our consolidated financial statements and disclosures.

ASU 2016-15, Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payments

In August 2016, the FASB issued ASU 2016-15, which amends the guidance on the classification of certain cash receipts and payments in the statement of cash flows. The adoption of this guidance did not have any impact on our consolidated financial statements and disclosures.

ASU 2016-01, Recognition and Measurement of Financial Instruments

In January 2016, the FASB issued ASU 2016-01, which amends the guidance on the classification and measurement of financial instruments. Although the ASU retains many of the current requirements, it significantly revises an entity’s accounting related to (1) the classification and measurement of investments in equity securities, and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. The ASU also amends certain disclosure requirements associated with the fair value of financial instruments.

In February 2018, the FASB also issued ASU 2018-03, Technical Corrections and Improvements to Financial Instruments - Recognition and Measurement of Financial Assets and Financial Liabilities, which clarifies that entities should use a prospective transition approach only for equity securities they elect to measure using the new measurement alternative. The amendments also clarify that an entity that voluntarily discontinues using the measurement alternative for an equity security without a readily determinable fair value must measure that security and all identical or similar investments of the same issuer at fair value. Under this guidance, this election is irrevocable and will apply to all future purchases of identical or similar investments of the same issuer. The amendments also clarify other aspects of ASU 2016-01 on how to apply the measurement alternative and the presentation requirements for financial liabilities measured under the fair value option. The adoption of this guidance is contingent on the adoption of ASU 2016-01.

We adopted ASU 2016-01 on January 1, 2018 using the modified retrospective approach and recorded a cumulative-effect adjustment of $1.6 million to reduce opening retained earnings for certain of our other investments that were previously classified as available-for-sale securities and for which changes in fair value were previously included in accumulated other comprehensive income. We also adopted ASU 2018-03 following our adoption of ASU 2016-01 and this adoption did not have any impact on our consolidated financial statements and related disclosures.

ASUs 2014-09, 2016-08, 2016-10, 2016-12, Revenue from Contracts with Customers

In May 2014, the FASB issued ASU 2014-09, which outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. The ASU applies to all contracts with customers except those that are within the scope of other FASB topics, primarily our premium revenues which are covered by ASC 944 - Financial Services - Insurance, and revenues from our investment portfolios which are covered by other FASB topics. While contracts within the scope of ASC 944 are excluded from the scope of the ASU, certain insurance-related contracts are within the scope of the ASU, for example contracts under which service providers charge their customers fixed fees in exchange for an agreement to provide services for an uncertain future event. Certain of the ASU’s provisions also apply to transfers of non-financial assets and include guidance on recognition and measurement.

In March 2016, the FASB also issued ASU 2016-08, Revenue from Contracts with Customers - Principal versus Agent Considerations, which clarifies the implementation guidance for principal versus agent considerations in ASU 2014-09. In April 2016, the FASB then issued ASU 2016-10, Revenue from Contracts with Customers - Identifying Performance Obligations and Licensing, which amends the guidance in ASU 2014-09 related to identifying performance obligations and accounting for licenses of intellectual property. In May 2016, the FASB further issued ASU 2016-12, Revenue from Contracts with Customers - Narrow-Scope Improvements and Practical Expedients, which clarifies the following aspects in ASU 2014-09 - (1a) collectability, (2) presentation of sales taxes and other similar taxes collected from customers, (3) non-cash considerations, (4) contract modifications at transition, (5) completed contracts at transition, and (6) technical correction.

We adopted ASU 2014-09 and the related amendments, as codified in ASC 606 - Revenue from Contracts with Customers, on January 1, 2018 using the modified retrospective method with prior periods not being restated. Premium revenues and those related to our investment portfolios, which collectively comprise most of our total revenues, are within the scope of other FASB topics and therefore are excluded from the scope of the revenue recognition standard. For other revenue types, which are within the scope of the new guidance, we evaluated individual contracts against the provisions of the new guidance to identify any contracts where the timing and measurement of those revenues may differ based upon the new guidance. The adoption did not have a material impact on our consolidated financial statements and related disclosures.

Recently Issued Accounting Pronouncements Not Yet Adopted

Note 2 - "Significant Accounting Policies" to the consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2017 describes accounting pronouncements that were not adopted as of December 31, 2017. Those pronouncements are not yet adopted unless discussed above in "New Accounting Standards Adopted in 2018." In addition, the following relevant pronouncements were issued during the nine months ended September 30, 2018 or thereafter and are yet to be adopted.

ASU 2018-17, Targeted Improvements to Related Party Guidance for Variable Interest Entities

In October 2018, the FASB issued ASU 2018-17, which clarifies that when determining whether a decision-making fee is a variable interest, a reporting entity should consider indirect interests held through related parties under common control on a proportional basis rather than as the equivalent of a direct interest in its entirety, as currently required in GAAP. This amendment will, (1) likely result in more decision makers not having a variable interest through their decision-making arrangements, and (2) create alignment between determining whether a decision-making fee is a variable interest and determining whether a reporting entity within a related party group is the primary beneficiary of a variable interest entity ("VIE"). The ASU is effective for interim and annual reporting periods beginning after December 15, 2019, although early adoption is permitted. All entities are required to apply this guidance retrospectively with a cumulative-effect adjustment to retained earnings at the beginning of the earliest period presented. While some of our subsidiaries are involved in certain decision-making arrangements for which they earn fees that are considered variable interests, they do not meet the primary beneficiary definition under the VIE guidance with respect to these arrangements. Therefore, we do not expect the adoption of this guidance to have a material impact on our consolidated financial statements and the related disclosures.

ASU 2018-13, Changes to the Disclosure Requirements for Fair Value Measurements

In August 2018, the FASB issued ASU 2018-13, which amended the fair value measurement guidance in ASC 820 - Fair Value Measurement, by removing and modifying certain existing disclosure requirements, while also adding new disclosure requirements. The ASU is effective for interim and annual reporting periods beginning after December 15, 2019, although early adoption is permitted, with the amendments being applied either prospectively or retrospectively, as specified in the ASU. In addition, an entity may elect to early adopt the removal or modification of disclosures immediately and delay the adoption of the new disclosure requirements until the effective date. We are currently assessing the impact of adopting this guidance however we do not expect the new or modified disclosures to have a material impact on the disclosures in our consolidated financial statements.

ASU 2018-12, Targeted Improvements to the Accounting for Certain Long-Duration Insurance Contracts

In August 2018, the FASB issued ASU 2018-12, which amends the accounting and disclosure model for certain long-duration insurance contracts under U.S GAAP. The goal of the ASU's amendments is to improve the following aspects of financial reporting related to long-duration insurance contracts: (1) measurement of the liability for future policy benefits related to non-participating traditional and limited-payment contracts, (2) measurement and presentation of market risk benefits, (3) amortization of deferred acquisition costs, and (4) presentation and disclosures. The ASU is effective for interim and annual reporting periods beginning after December 15, 2020, although early adoption is permitted. Once the transfer of our remaining life insurance policies from our subsidiary Alpha Insurance SA to Monument Insurance Group Limited is completed, as discussed in Note 11 - "Policy Benefits for Life Contracts", we will not have any residual exposures relating to long duration insurance contracts. Therefore, the adoption of this guidance is not expected to have a material impact on our consolidated financial statements and related disclosures.

ASU 2018-11, Targeted Improvements to ASC 842 - Leases and ASU 2018-10, Codification Improvements to ASC 842 - Leases

In July 2018, the FASB issued ASU 2018-11, which adds a transition option for all entities and a practical expedient only for lessors to the ASU 2016-02 - Leases guidance initially issued by the FASB in February 2016 and codified in ASC 842. The transition option which we will elect, allows entities to not apply the new leases standard in the comparative periods they present in their financial statements in the year of adoption. Under the transition option, entities can opt to continue to apply the legacy guidance in ASC 840 - Leases, including its disclosure requirements, in the comparative periods presented in the year they adopt the new leases standard. This means that entities that elect this option will only provide annual disclosures for the comparative periods because ASC 840 does not require interim disclosures. Entities that elect this transition option will still be required to adopt the new leases standard using the modified retrospective transition method required by the standard, but they will recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption rather than in the earliest period presented. The practical expedient provides lessors with an option to not separate the non-lease components from the associated lease components when certain criteria are met and requires them to account for the combined component in accordance with the revenue recognition standard in ASC 606 if the associated non-lease components are the predominant components.

In July 2018, the FASB also issued ASU 2018-10, which clarifies how to apply certain aspects of ASC 842. The amendments in the ASU address a number of issues in the new leases guidance, including (a) the rate implicit in the lease, (b) impairment of the net investment in the lease, (c) lessee reassessment of lease classification, (d) lessor reassessment of lease term and purchase options, (e) variable payments that depend on an index or rate, and (f) certain transition adjustments.

The amendments arising from both ASU 2018-11 and ASU 2018-10 have the same effective date and transition requirements as ASC 842, which we expect to adopt on January 1, 2019, when it becomes effective. Being a financial services company, the majority of our operating leases cover office space and facilities required to conduct our operations. Therefore on adoption of the leases guidance, we do not expect the right-of-use asset and the corresponding lease liability to be recorded relating to these operating lease arrangements, to be material as a proportion of our total assets and liabilities. In addition, the leases guidance is not expected to have a significant impact on the net lease expense that we will recognize in our consolidated statements of earnings as a result of our operating lease arrangements.

ASU 2018-09, Codification Improvements

In July 2018, the FASB issued ASU 2018-09, which affects a wide variety of Topics in the Codification and applies to all reporting entities within the scope of the affected accounting guidance. The amendments in the ASU represent changes that clarify, correct errors in, or make minor improvements to the Codification. Ultimately, the amendments make the Codification easier to understand and apply by eliminating inconsistencies and providing clarifications. Some of the amendments in this ASU do not require transition guidance and are effective upon issuance of the ASU, while many of the amendments have transition guidance with effective dates for annual periods beginning after December 15, 2018. The adoption of the amendments in this ASU are not expected to have a material impact on our consolidated financial statements and related disclosures.

Acquisitions

9 Months Ended

Sep. 30, 2018

Business Combinations [Abstract]

Acquisitions

2. ACQUISITIONS

Maiden Re North America

On August 31, 2018, we entered into a definitive agreement to acquire Maiden Reinsurance North America, Inc. (“Maiden Re North America”) from a subsidiary of Maiden Holdings, Ltd. Maiden Re North America is a diversified insurance company domiciled in Missouri that provides property and casualty treaty reinsurance, casualty facultative reinsurance and accident and health treaty reinsurance. As part of the transaction, we will novate and assume certain reinsurance agreements from Maiden Re North America's Bermuda reinsurer, including certain reinsurance agreements with Maiden Re North America.

The net consideration payable in the transaction is $307.5 million, subject to certain closing adjustments. We will assume approximately $1.3 billion of net loss and loss adjustment expense reserves and unearned premium reserves upon closing.

We will operate the business in run-off, and we expect to finance the purchase price through a combination of cash on hand and borrowings under our revolving credit facility. Completion of the transaction is conditioned on, among other things, governmental and regulatory approvals and satisfaction of various customary closing conditions. The transaction is expected to close in the fourth quarter of 2018.

KaylaRe

Overview

On May 14, 2018, we completed the previously announced transaction to acquire all of the outstanding shares and warrants of KaylaRe Holdings, Ltd. ("KaylaRe"). In consideration for the acquired shares and warrants of KaylaRe, we issued an aggregate of 2,007,017 ordinary shares to the shareholders of KaylaRe, comprising 1,501,778 voting ordinary shares and 505,239 Series E non-voting ordinary shares. Effective May 14, 2018, we consolidated KaylaRe into our consolidated financial statements, and any balances between KaylaRe and Enstar are now eliminated upon consolidation.

The completion of the KaylaRe transaction enhanced our group capital position and enabled the Company to assume full ownership of another platform from which we can provide non-life run-off solutions to our clients.

Refer to Note 20 - "Related Party Transactions" for additional information relating to KaylaRe.

Purchase Price

The components of the consideration paid to acquire all of the outstanding shares and warrants of KaylaRe were as follows:



Fair value of Enstar ordinary shares issued	$	414,750
Fair value of previously held equity method investment	336,137
Adjustment for the fair value of preexisting relationships	37,169
Total purchase price	$	788,056
Net assets acquired at fair value (excluding preexisting relationships)	$	746,320
Excess of purchase price over fair value of net assets acquired	$	41,736

The purchase price was allocated to the acquired assets and liabilities of KaylaRe based on their estimated fair values at the acquisition date. We recognized goodwill of $41.7 million on the transaction, primarily attributable to (i) the capital synergies from integrating KaylaRe into our group capital structure, (ii) investment management capabilities on a total return basis, and (iii) the incremental acquired capital to be utilized for future non-life run-off transactions.

Fair Value of Enstar Ordinary Shares Issued

The fair value of the Enstar ordinary shares issued was based on the closing price of $206.65 as at May 14, 2018, the date the transaction closed.



Number of Enstar Ordinary shares issued	2,007,017
Closing price of Enstar Ordinary shares as of May 14, 2018	$	206.65
Fair value of Enstar Ordinary shares issued to shareholders of KaylaRe	$	414,750

Fair Value of Previously Held Equity Method Investment

Prior to the close of the transaction, Enstar held a 48.2% interest in KaylaRe, which was accounted for as an equity method investment in accordance with ASC 323 - Investments - Equity Method and Joint Ventures. The acquisition of the remaining 51.8% equity interest in KaylaRe was considered a step acquisition, whereby we remeasured the previously held equity method investment to fair value. We considered multiple factors in determining the fair value of the previously held equity method investment, including, (i) the price negotiated with the selling shareholders for the 51.8% equity interest in KaylaRe, (ii) recent market transactions for similar companies, and (iii) current trading multiples for comparable companies. Based on this analysis, a valuation multiple of 1.05 to KaylaRe's carrying book value was determined to be appropriate to remeasure the previously held equity method investment at fair value. This resulted in the recognition of a gain of $16.0 million on completion of the step acquisition of KaylaRe, which was recorded in other income (loss) during the three months ended June 30, 2018.



Carrying value of previously held equity method investment prior to the close of the transaction	$	320,130
Price-to-book multiple	1.05
Fair value of previously held equity method investment prior to the close of the transaction	$	336,137

Gain recognized on remeasurement of previously held equity method investment to fair value	$	16,007

Adjustment for the Fair Value of Preexisting Relationships

Enstar had contractual preexisting relationships with KaylaRe, which were deemed to be effectively settled at fair value on the acquisition date. The differences between the carrying value and the fair value of the preexisting relationships was included as part of the purchase price in accordance with ASC 805 - Business Combinations. The fair value of the balances relating to preexisting reinsurance relationships with KaylaRe was determined using a discounted cash flow approach and, where applicable, consideration was given to stated contractual settlement provisions, when determining the loss to be recorded on the deemed settlement of these preexisting relationships. The fair values of the balances arising from the non-reinsurance preexisting relationships with KaylaRe were deemed to equal their carrying values given their short-term nature and the expectation that they would all be settled within the next twelve months.

As a result of effectively settling all the contractual preexisting relationships with KaylaRe, the Company recognized a loss of $15.6 million which was recorded in other income (loss) in the three months ended June 30, 2018, as summarized below:



ASSETS	Carrying value			Fair value			Loss on deemed settlement
Funds held by reinsured companies	$	386,793		$	386,793		$	—
Deferred acquisition costs/Value of business acquired	33,549			40,268			6,719
TOTAL ASSETS	420,342			427,061			6,719
LIABILITIES
Losses and LAE	339,747			333,205			(6,542		)
Unearned premiums	105,602			105,602			—
Insurance and reinsurance balances payable	25,897			23,559			(2,338		)
Other liabilities	1,864			1,864			—
TOTAL LIABILITIES	473,110			464,230			(8,880		)
NET ASSETS (LIABILITIES)	$	(52,768	)	$	(37,169	)	$	15,599

Fair Value of Net Assets Acquired and Liabilities Assumed

The following table summarizes the fair values of the assets acquired and liabilities assumed (excluding preexisting relationships) in the KaylaRe transaction at the acquisition date, which have all been allocated to the Non-life Run-off segment.



ASSETS
Fixed maturities, trading, at fair value	$	126,393
Other investments, at fair value	626,476
Total investments	752,869
Cash and cash equivalents	5,657
Premiums receivable	10,965
Deferred acquisition costs	275
Other assets	614
TOTAL ASSETS	$	770,380
LIABILITIES
Losses and LAE	$	4,059
Unearned premiums	10,984
Insurance and reinsurance balances payable	13
Other liabilities	9,004
TOTAL LIABILITIES	24,060
NET ASSETS ACQUIRED AT FAIR VALUE	$	746,320

The table below summarizes the results of the KaylaRe operations which are included in our condensed consolidated statement of earnings from the acquisition date to September 30, 2018:



Premiums earned	$	10,188
Incurred losses and LAE	(9,190		)
Acquisition costs	(332		)
Underwriting income	666
Net investment income	1,972
Net unrealized gains	(6,621		)
General and administrative expenses	(573		)
Net loss	$	(4,556	)

Significant New Business	9 Months Ended
Significant New Business	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
SIGNIFICANT NEW BUSINESS	3. SIGNIFICANT NEW BUSINESS Coca-Cola On August 1, 2018, we entered into a reinsurance transaction with The Coca-Cola Company and its subsidiaries ("Coca-Cola"), pursuant to which we reinsured certain of Coca-Cola's retention and deductible risks under its subsidiaries' U.S. workers' compensation, auto liability, general liability and product liability insurance coverage. We assumed total gross reserves of $120.8 million for cash consideration of $103.6 million and recorded a deferred charge of $17.2 million, included in other assets. We transferred the cash consideration received of $103.6 million into a trust to support our obligations under the reinsurance agreement. Zurich Australia On February 23, 2018, we entered into a reinsurance agreement with Zurich Australian Insurance Limited, a subsidiary of Zurich Insurance Group ("Zurich") to reinsure its New South Wales Vehicle Compulsory Third Party ("CTP") insurance business. Under the agreement, which was effective as of January 1, 2018, we assumed gross loss reserves of AUD$359.4 million ($280.8 million) in exchange for a reinsurance premium consideration of AUD$343.9 million ($268.7 million). We elected the fair value option for this reinsurance contract and recorded an initial fair value adjustment of AUD$15.5 million ($12.1 million) on the assumed gross loss reserves. Refer to Note 7 - "Fair Value Measurements" for a description of the fair value process and the assumptions made. Following the initial reinsurance transaction, which transferred the economics of the CTP insurance business, we and Zurich are pursuing a portfolio transfer of the CTP insurance business under Division 3A Part III of Australia's Insurance Act 1973 (Cth), which will provide legal finality for Zurich's obligations. The transfer is subject to court, regulatory and other approvals. Neon RITC Transaction On February 16, 2018, we completed a reinsurance-to-close (“RITC”) transaction with Neon Underwriting Limited ("Neon"), under which we reinsured to close the 2015 and prior underwriting years of account (comprising underwriting years 2008 to 2015) of Neon's Syndicate 2468, with effect from January 1, 2018. We assumed gross loss reserves of £403.9 million ($546.3 million) and net loss reserves of £342.1 million ($462.6 million) relating to the portfolio in exchange for a reinsurance premium consideration of £329.1 million ($445.1 million). We elected the fair value option for this reinsurance contract and recorded initial fair value adjustments of $20.6 million and $17.5 million on the gross and net loss reserves assumed, respectively. Refer to Note 7 - "Fair Value Measurements" for a description of the fair value process and the assumptions made. Following the closing of the transaction, we have taken responsibility for claims handling and provided complete finality to Neon's obligations. Novae RITC Transaction On January 29, 2018, we entered into an RITC transaction with AXIS Managing Agency Limited, under which we reinsured to close the 2015 and prior underwriting years of account of Novae Syndicate 2007 ("Novae"), with effect from January 1, 2018. We assumed gross loss reserves of £860.1 million ($1,163.2 million) and net loss reserves of £630.7 million ($853.0 million) relating to the portfolio in exchange for a reinsurance premium consideration of £594.1 million ($803.5 million). We elected the fair value option for this reinsurance contract and recorded initial fair value adjustments of $67.5 million and $49.5 million on the gross and net loss reserves assumed, respectively. Refer to Note 7 - "Fair Value Measurements" for a description of the fair value process and the assumptions made. Following the closing of the transaction, we have taken responsibility for claims handling and provided complete finality to Novae's obligations.

Divestitures, Held-For-Sale Businesses and Discontinued Operations

9 Months Ended

Sep. 30, 2018

Discontinued Operations and Disposal Groups [Abstract]

DIVESTITURES, HELD-FOR-SALE BUSINESSES AND DISCONTINUED OPERATIONS

4. DIVESTITURES, HELD-FOR-SALE BUSINESSES AND DISCONTINUED OPERATIONS

Pavonia

On December 29, 2017, we completed the previously announced sale of our subsidiary, Pavonia Holdings (US) Inc. ("Pavonia"), to Southland National Holdings, Inc. ("Southland"), a Delaware corporation and a subsidiary of Global Bankers Insurance Group, LLC. The aggregate purchase price was $120.0 million. We used the proceeds to make repayments under its revolving credit facility.

Pavonia owns Pavonia Life Insurance Company of Michigan (“PLIC MI”) and Enstar Life (US), Inc. Pursuant to the amended stock purchase agreement between us and Southland, which partially restructured the transaction, Southland has agreed to acquire Pavonia Life Insurance Company of New York ("PLIC NY") for $13.1 million in a second closing that is subject to regulatory approval. In the event that the second closing has not occurred by December 29, 2018 (unless further extended by the parties), we will evaluate strategic alternatives for PLIC NY, which may include the pursuit of an alternative sale transaction or a plan to retain the business. The additional purchase price represents the cash consideration we paid to PLIC MI when we acquired PLIC NY from PLIC MI as a result of the restructuring of the first closing of the transaction.

Pavonia was a substantial portion of our previously reported Life and Annuities segment. We classified the assets and liabilities of the businesses to be sold as held-for-sale. The following table summarizes the components of assets and liabilities held-for-sale on our consolidated balance sheet as at December 31, 2017:



	December 31, 2017
Assets:
Fixed maturities, trading, at fair value	$	20,770
Equities, trading, at fair value	765
Cash and cash equivalents	6,314
Restricted cash and cash equivalents	13
Reinsurance balances recoverable	1,728
Other assets	269
Assets of businesses held for sale	29,859
Less: Accrual of loss on sale	(5,508		)
Total assets held for sale	$	24,351

Liabilities:
Policy benefits for life and annuity contracts	$	10,666
Other liabilities	605
Total liabilities held-for-sale	$	11,271

As at December 31, 2017, included in the table above were restricted investments of $1.4 million.

As at September 30, 2018, included within Other assets and Other liabilities on our consolidated balance sheet were amounts of $23.3 million and $10.3 million, respectively, relating to PLIC NY.

The Pavonia business qualified as a discontinued operation during the three and nine months ended September 30, 2017. The following table summarizes the components of net earnings from discontinued operations on the unaudited condensed consolidated statements of earnings for the three and nine months ended September 30, 2017:



	Three Months Ended			Nine Months Ended
	September 30,			September 30,
	2017			2017
INCOME
Net premiums earned	$	14,082		$	42,012
Net investment income	10,077			30,383
Net realized and unrealized gains (losses)	(233		)	2,543
Other income	384			1,139
	24,310			76,077
EXPENSES
Life and annuity policy benefits	15,320			60,102
Acquisition costs	2,412			6,728
General and administrative expenses	2,809			9,584
Other expenses	4			(12		)
	20,545			76,402
EARNINGS (LOSSES) BEFORE INCOME TAXES	3,765			(325		)
INCOME TAXES	(270		)	(680		)
NET EARNINGS (LOSS) FROM DISCONTINUED OPERATIONS	$	3,495		$	(1,005	)

The following table presents the cash flows of Pavonia for the nine months ended September 30, 2017:



	Nine Months Ended September 30,
	2017
Operating activities	$	42,558
Investing activities	8,129
Change in cash of businesses held-for-sale	$	50,687

Laguna

On August 29, 2017, we completed a transaction to sell Laguna Life DAC (“Laguna”) for total consideration of €25.6 million (approximately $30.8 million) to a subsidiary of Monument Re Limited ("Monument"). We have an investment in Monument, as described further in Note 20 - "Related Party Transactions". Laguna was classified as held-for-sale during 2017 prior to its sale.

The net losses relating to Laguna for the three and nine months ended September 30, 2017 were $0.9 million and $1.1 million, respectively. These amounts were not significant to our consolidated operations and therefore we did not classify Laguna as a discontinued operation for prior periods. Following the closing of the sale of Laguna, we recorded a loss on sale of subsidiary of $6.7 million and $16.3 million for the three and nine months ended September 30, 2017, respectively, which was included in earnings from continuing operations before income taxes in our consolidated statement of earnings. The total loss recorded on the sale of Laguna of $16.3 million included a cumulative currency translation adjustment balance of $6.3 million, which upon completion of the sale during the third quarter of 2017 was reclassified from accumulated other comprehensive income and included in earnings as a component of the loss on sale of Laguna.

Investments

9 Months Ended

Sep. 30, 2018

Investments, Debt and Equity Securities [Abstract]

INVESTMENTS

5. INVESTMENTS

We hold: (i) trading portfolios of fixed maturity investments, short-term investments and equities, carried at fair value; (ii) available-for-sale portfolios of fixed maturity carried at fair value; and (iii) other investments carried at either fair value or cost.

Trading

The fair values of our fixed maturity investments, short-term investments and equities classified as trading were as follows:



	September 30, 2018		December 31, 2017
U.S. government and agency	$	493,080	$	554,036
Non-U.S. government	1,018,212		607,132
Corporate	3,703,029		3,363,060
Municipal	76,599		100,221
Residential mortgage-backed	275,485		288,713
Commercial mortgage-backed	411,575		421,548
Asset-backed	567,300		541,574
Total fixed maturity and short-term investments	6,545,280		5,876,284
Equities — U.S.	72,765		106,363
Equities — International	57,549		240
	$	6,675,594	$	5,982,887

Included within residential and commercial mortgage-backed securities as at September 30, 2018 were securities issued by U.S. governmental agencies with a fair value of $147.3 million (as at December 31, 2017: $152.4 million). Included within corporate securities as at September 30, 2018 were senior secured loans of $24.3 million (as at December 31, 2017: $68.9 million).

The contractual maturities of our fixed maturity and short-term investments classified as trading are shown below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties.



As at September 30, 2018	Amortized Cost		Fair Value		% of Total Fair Value
One year or less	$	428,656	$	424,195	6.5	%
More than one year through two years	544,754		531,717		8.1	%
More than two years through five years	1,641,037		1,601,237		24.4	%
More than five years through ten years	1,506,829		1,464,185		22.4	%
More than ten years	1,301,979		1,269,586		19.4	%
Residential mortgage-backed	274,833		275,485		4.2	%
Commercial mortgage-backed	423,471		411,575		6.3	%
Asset-backed	567,538		567,300		8.7	%
	$	6,689,097	$	6,545,280	100.0	%

Available-for-sale

The amortized cost and fair values of our fixed maturity investments classified as available-for-sale were as follows:



As at September 30, 2018	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses (Non-OTTI)			Fair Value
U.S. government and agency	$	703	$	—	$	(5	)	$	698
Non-U.S. government	75,741		851		(1,036		)	75,556
Corporate	83,836		1,085		(1,413		)	83,508
Municipal	3,401		—		(34		)	3,367
Residential mortgage-backed	15		—		—			15
	$	163,696	$	1,936	$	(2,488	)	$	163,144



As at December 31, 2017	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses (Non-OTTI)			Fair Value
U.S. government and agency	$	4,210	$	—	$	(23	)	$	4,187
Non-U.S. government	84,776		1,249		(588		)	85,437
Corporate	113,561		2,436		(876		)	115,121
Municipal	5,146		8		(18		)	5,136
Residential mortgage-backed	31		—		—			31
Asset-backed	373		—		—			373
	$	208,097	$	3,693	$	(1,505	)	$	210,285

The contractual maturities of our fixed maturity investments classified as available-for-sale are shown below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties.



As at September 30, 2018	Amortized Cost		Fair Value		% of Total Fair Value
One year or less	$	18,265	$	17,641	10.8	%
More than one year through two years	26,556		26,332		16.2	%
More than two years through five years	31,604		31,634		19.4	%
More than five years through ten years	55,804		55,818		34.2	%
More than ten years	31,452		31,704		19.4	%
Residential mortgage-backed	15		15		—	%
	$	163,696	$	163,144	100.0	%

Gross Unrealized Losses

The following tables summarize our fixed maturity investments classified as available-for-sale that are in a gross unrealized loss position:



	12 Months or Greater					Less Than 12 Months					Total
As at September 30, 2018	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Fixed maturity investments, at fair value
U.S. government and agency	$	698	$	(5	)	$	—	$	—		$	698	$	(5	)
Non-U.S. government	4,233		(406		)	21,719		(630		)	25,952		(1,036		)
Corporate	8,562		(917		)	33,808		(496		)	42,370		(1,413		)
Municipal	617		(12		)	2,750		(22		)	3,367		(34		)
Total fixed maturity investments	$	14,110	$	(1,340	)	$	58,277	$	(1,148	)	$	72,387	$	(2,488	)



	12 Months or Greater					Less Than 12 Months					Total
As at December 31, 2017	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Fixed maturity investments, at fair value
U.S. government and agency	$	2,344	$	(16	)	$	1,842	$	(7	)	$	4,186	$	(23	)
Non-U.S. government	11,101		(373		)	20,965		(215		)	32,066		(588		)
Corporate	9,177		(807		)	24,200		(69		)	33,377		(876		)
Municipal	369		(5		)	3,605		(13		)	3,974		(18		)
Total fixed maturity investments	$	22,991	$	(1,201	)	$	50,612	$	(304	)	$	73,603	$	(1,505	)

As at September 30, 2018 and December 31, 2017, the number of securities classified as available-for-sale in an unrealized loss position was 103 and 96, respectively. Of these securities, the number of securities that had been in an unrealized loss position for twelve months or longer was 33 and 37, respectively.

Other-Than-Temporary Impairment

For the nine months ended September 30, 2018 and 2017, we did not recognize any other-than-temporary impairment losses on our available-for-sale securities. We determined that no credit losses existed as at September 30, 2018 or December 31, 2017. A description of our other-than-temporary impairment process is included in Note 2 - "Significant Accounting Policies" to the consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2017. There were no changes to our process during the nine months ended September 30, 2018.

Credit Ratings

The following table sets forth the credit ratings of our fixed maturity (including both trading and available-for-sale investments) and short-term investments as at September 30, 2018:



	Amortized Cost		Fair Value		% of Total Investments		AAA Rated			AA Rated			A Rated			BBB Rated			Non- Investment Grade			Not Rated
Fixed maturity and short-term investments
U.S. government and agency	$	502,168	$	493,778	7.4	%	$	489,939		$	3,839		$	—		$	—		$	—		$	—
Non-U.S. government	1,109,697		1,093,768		16.3	%	340,583			541,087			65,286			121,197			25,615			—
Corporate	3,893,368		3,786,537		56.4	%	154,961			445,858			1,986,880			1,016,401			180,730			1,707
Municipal	81,703		79,966		1.2	%	8,739			53,094			14,277			3,856			—			—
Residential mortgage-backed	274,848		275,500		4.1	%	163,190			2,526			11,331			1,540			92,180			4,733
Commercial mortgage-backed	423,471		411,575		6.1	%	210,902			47,118			70,164			60,296			9,936			13,159
Asset-backed	567,538		567,300		8.5	%	237,239			46,971			115,349			73,415			93,918			408
Total	$	6,852,793	$	6,708,424	100.0	%	$	1,605,553		$	1,140,493		$	2,263,287		$	1,276,705		$	402,379		$	20,007
% of total fair value							23.9		%	17.0		%	33.8		%	19.0		%	6.0		%	0.3		%

Other Investments, at fair value

The following table summarizes our other investments carried at fair value:



	September 30, 2018		December 31, 2017
Private equities and private equity funds	$	256,618	$	289,556
Fixed income funds	383,328		229,999
Hedge funds	879,571		63,773
Equity funds	381,983		249,475
CLO equities	48,368		56,765
CLO equity fund	41,501		12,840
Private credit funds	39,751		10,156
Call options on equity	4,590		—
Other	720		828
	$	2,036,430	$	913,392

The valuation of our other investments is described in Note 7 - "Fair Value Measurements". Due to a lag in the valuations of certain funds reported by the managers, we may record changes in valuation with up to a three-month lag. We regularly review and discuss fund performance with the fund managers to corroborate the reasonableness of the reported net asset values and to assess whether any events have occurred within the lag period that would affect the valuation of the investments. The following is a description of the nature of each of these investment categories:


•	Private equities and private equity funds invest primarily in the financial services industry. All of our investments in private equities and private equity funds are subject to restrictions on redemptions and sales that are determined by the governing documents and limit our ability to liquidate those investments. These restrictions have been in place since the dates of our initial investments.

•

Fixed income funds comprise a number of positions in diversified fixed income funds that are managed by third-party managers. Underlying investments vary from high-grade corporate bonds to non-investment grade senior secured loans and bonds, but are generally invested in liquid fixed income markets. These funds have regularly published prices. One of our funds has a lock-up period of up to two years and is eligible for quarterly redemptions thereafter with 65 days notice. All other funds have liquidity terms that vary from daily up to 45 day's notice. Investments of $0.3 million in fixed income funds were subject to gates or side-pockets, where redemptions are subject to the sale of underlying investments. A gate is the ability to deny or delay a redemption request, whereas a side-pocket is a designated account for which the investor loses its redemption rights.

•

Hedge funds may invest in a wide range of instruments, including debt and equity securities, and utilize various sophisticated strategies to achieve their objectives. We invest in a mixture of fixed income, equity and multi-strategy hedge funds. Our hedge funds have various lock-up periods of up to three years and redemption terms, predominantly 60 and 90 days. Certain of our hedge funds which are past their lock up periods are currently eligible for redemption while others are still in the lock-up period.


•	Equity funds invest in a diversified portfolio of U.S. and international publicly-traded equity securities. The funds have liquidity terms that vary from daily up to quarterly.


•	CLO equities comprise investments in the equity tranches of term-financed securitizations of diversified pools of corporate bank loans. CLO equities denote direct investments by us in these securities.


•	CLO equity fund invests primarily in the equity tranches of term-financed securitizations of diversified pools of corporate bank loans. The fund has a fair value of $41.5 million and is eligible for redemption.


•	Private credit funds invest in direct senior or collateralized loans. The investments are subject to restrictions on redemption and sales that are determined by the governing documents and limit our ability to liquidate our positions in the funds.


•	Call options on equities comprise directly held options to purchase the common equity of publicly traded corporations.


•	Other primarily comprises a fund that provides loans to educational institutions throughout the United States and its territories.

The increase in our other investments carried at fair value between December 31, 2017 and September 30, 2018 was primarily attributable to $626.5 million of other investments acquired as part of the KaylaRe acquisition and net additional subscriptions of $538.1 million.

As at September 30, 2018, we had unfunded commitments to private equity funds of $200.0 million.

Other Investments, at cost

During the three months ended June 30, 2018, we sold our investments in life settlement contracts, which were carried at cost. During the nine months ended September 30, 2018 and 2017, net investment income included $6.5 million and $10.6 million, respectively, related to investments in life settlements. There were impairment charges of $6.6 million and $7.5 million recognized in net realized and unrealized gains/losses during the nine months ended September 30, 2018 and 2017, respectively, related to investments in life settlements.

Net Investment Income

Major categories of net investment income for the three and nine months ended September 30, 2018 and 2017 are summarized as follows:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Fixed maturity investments	$	48,062		$	37,931		$	140,097		$	102,002
Short-term investments and cash and cash equivalents	3,247			2,048			8,425			7,489
Funds held	1,502			247			8,651			597
Funds held - directly managed	9,776			8,516			27,990			24,121
Investment income from fixed maturities and cash and cash equivalents	62,587			48,742			185,163			134,209
Equity securities	946			1,344			3,788			3,207
Other investments	8,324			3,120			14,600			10,016
Life settlements and other	—			1,443			6,509			11,026
Investment income from equities and other investments	9,270			5,907			24,897			24,249
Gross investment income	71,857			54,649			210,060			158,458
Investment expenses	(2,427		)	(2,621		)	(7,842		)	(8,274		)
Net investment income	$	69,430		$	52,028		$	202,218		$	150,184

Net Realized and Unrealized Gains and Losses

Components of net realized and unrealized gains and losses for the three and nine months ended September 30, 2018 and 2017 were as follows:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Net realized gains (losses) on sale:
Gross realized gains on fixed maturity securities, available-for-sale	$	—		$	8		$	27		$	345
Gross realized losses on fixed maturity securities, available-for-sale	(2		)	(5		)	(80		)	(91		)
Net realized gains (losses) on fixed maturity securities, trading	(8,797		)	4,595			(19,310		)	3,608
Net realized gains on equity securities, trading	666			340			3,569			1,150
Net realized gains (losses) on funds held - directly managed	(1,904		)	422			(2,849		)	(3,720		)
Total net realized gains (losses) on sale	$	(10,037	)	$	5,360		$	(18,643	)	$	1,292
Net unrealized gains (losses):
Fixed maturity securities, trading	$	(13,423	)	$	(10,747	)	$	(159,691	)	$	23,795
Equity securities, trading	1,830			2,652			6,152			13,209
Other Investments	(35,188		)	27,802			(37,059		)	71,007
Change in fair value of embedded derivative on funds held – directly managed	(182		)	3,967			(41,107		)	28,807
Change in value of fair value option on funds held - directly managed	(223		)	267			(4,323		)	1,587
Total net unrealized gains (losses)	(47,186		)	23,941			(236,028		)	138,405
Net realized and unrealized gains (losses)	$	(57,223	)	$	29,301		$	(254,671	)	$	139,697

The gross realized gains and losses on available-for-sale securities included in the table above resulted from sales of $0.4 million and $5.9 million for the three months ended September 30, 2018 and 2017, respectively, and $10.9 million and $27.5 million for the nine months ended September 30, 2018 and 2017, respectively.

Restricted Assets

We are required to maintain investments and cash and cash equivalents on deposit to support our insurance and reinsurance operations. The investments and cash and cash equivalents on deposit are available to settle insurance and reinsurance liabilities. We also utilize trust accounts to collateralize business with our insurance and reinsurance counterparties. These trust accounts generally take the place of letter of credit requirements. The assets in trusts as collateral are primarily highly rated fixed maturity securities. The carrying value of our restricted assets, including restricted cash of $474.6 million and $257.7 million, as at September 30, 2018 and December 31, 2017, respectively, was as follows:



	September 30, 2018		December 31, 2017
Collateral in trust for third party agreements	$	3,354,994	$	3,118,892
Assets on deposit with regulatory authorities	563,139		599,829
Collateral for secured letter of credit facilities	134,286		151,467
Funds at Lloyd's ⁽¹⁾	422,657		234,833
	$	4,475,076	$	4,105,021

⁽¹⁾Our underwriting businesses include three Lloyd's syndicates. Lloyd's determines the required capital principally through the annual business plan of each syndicate. This capital is referred to as "Funds at Lloyd's" and will be drawn upon in the event that a syndicate has a loss that cannot be funded from other sources. On February 8, 2018, we amended and restated our unsecured letter of credit agreement for Funds at Lloyd's purposes ("FAL Facility") to issue up to $325.0 million letters of credit, with a provision to increase the facility up to $400.0 million, subject to lenders approval. The FAL Facility is available to satisfy our Funds at Lloyd's requirements and expires in 2022. As at September 30, 2018, our combined Funds at Lloyd's were comprised of cash and investments of $422.7 million and unsecured letters of credit of $295.0 million.

The increase in the collateral in trust for third-party agreements and Funds at Lloyd's was primarily due to the loss portfolio transfer reinsurance transactions as described in Note 3 - "Significant New Business".

Funds Held - Directly Managed

9 Months Ended

Sep. 30, 2018

Investments, Debt and Equity Securities [Abstract]

FUNDS HELD - DIRECTLY MANAGED

6. FUNDS HELD - DIRECTLY MANAGED

Funds held - directly managed is comprised of the following:

•

The funds held balance in relation to the Allianz transaction, described in Note 4 - "Significant New Business" in our consolidated financial statements in our Annual Report on Form 10-K for the year ended December 31, 2017. This receives a variable return reflecting the economics of the investment portfolio underlying the funds held asset and qualifies as an embedded derivative. We have recorded the aggregate of the funds held, typically held at cost, and the embedded derivative as a single amount in our consolidated balance sheet. As at September 30, 2018 and December 31, 2017, the funds held at cost had a carrying value of $1,074.1 million and $994.8 million, respectively, and the embedded derivative had a fair value of $(36.3) million and $4.7 million, respectively, the aggregate of which was $1,037.8 million and $999.5 million, respectively, as included in the table below.


•	The funds held balance in relation to the QBE reinsurance transaction described in Note 4 - "Significant New Business" in our consolidated financial statements in our Annual Report on Form 10-K for the year ended December 31, 2017, for which we elected the fair value option.

The following table presents the fair values of assets and liabilities underlying the funds held - directly managed account as at September 30, 2018 and December 31, 2017:



	September 30, 2018		December 31, 2017
Fixed maturity investments:
U.S. government and agency	$	98,928	$	69,850
Non-U.S. government	22,610		2,926
Corporate	641,460		695,490
Municipal	53,679		58,930
Residential mortgage-backed	70,196		29,439
Commercial mortgage-backed	220,077		211,186
Asset-backed	95,743		97,565
Total fixed maturity investments	$	1,202,693	$	1,165,386
Other assets	14,489		14,554
	$	1,217,182	$	1,179,940

The contractual maturities of the fixed maturity investments underlying the funds held - directly managed account are shown below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties.



As at September 30, 2018	Amortized Cost		Fair Value		% of Total Fair Value
One year or less	$	33,247	$	33,105	2.8	%
More than one year through two years	69,423		68,667		5.7	%
More than two years through five years	206,922		202,077		16.8	%
More than five years through ten years	287,706		277,396		23.1	%
More than ten years	246,045		235,432		19.6	%
Residential mortgage-backed	71,876		70,196		5.8	%
Commercial mortgage-backed	231,443		220,077		18.3	%
Asset-backed	95,877		95,743		7.9	%
	$	1,242,539	$	1,202,693	100.0	%

Credit Ratings

The following table sets forth the credit ratings of the fixed maturity investments underlying the funds held - directly managed account as at September 30, 2018:



	Amortized Cost		Fair Value		% of Total Investments		AAA Rated			AA Rated			A Rated			BBB Rated			Non- Investment Grade

U.S. government and agency	$	100,764	$	98,928	8.2	%	$	98,928		$	—		$	—		$	—		$	—
Non-U.S. government	22,537		22,610		1.9	%	—			3,827			12,088			6,695			—
Corporate	665,043		641,460		53.3	%	7,701			25,792			285,188			321,285			1,494
Municipal	54,999		53,679		4.5	%	—			16,555			29,960			7,164			—
Residential mortgage-backed	71,876		70,196		5.8	%	60,792			—			—			—			9,404
Commercial mortgage-backed	231,443		220,077		18.3	%	211,747			6,367			1,963			—			—
Asset-backed	95,877		95,743		8.0	%	75,417			16,289			4,037			—			—
Total	$	1,242,539	$	1,202,693	100.0	%	$	454,585		$	68,830		$	333,236		$	335,144		$	10,898
% of total fair value							37.8		%	5.7		%	27.7		%	27.9		%	0.9		%

Net Investment Income

Major categories of net investment income underlying the funds held - directly managed for the three and nine months ended September 30, 2018 and 2017 are summarized as follows:



	Three Months Ended						Nine Months Ended
	September 30						September 30
	2018			2017			2018			2017
Fixed maturity investments	$	10,014		$	8,702		$	28,649		$	25,004
Short-term investments and cash and cash equivalents	42			89			179			216
Gross investment income	10,056			8,791			28,828			25,220
Investment expenses	(280		)	(275		)	(838		)	(1,099		)
Investment income on funds held - directly managed	$	9,776		$	8,516		$	27,990		$	24,121

Net Realized Gains (Losses) and Change in Fair Value due to Embedded Derivative and Fair Value Option

Net realized gains (losses) and change in fair value for the three and nine months ended September 30, 2018 and 2017 are summarized as follows:



	Three Months Ended					Nine Months Ended
	September 30					September 30
	2018			2017		2018			2017
Net realized gains (losses) on fixed maturity securities	$	(1,904	)	$	422	$	(2,849	)	$	(3,720	)
Change in fair value of embedded derivative	(182		)	3,967		(41,107		)	28,807
Change in value of fair value option on funds held - directly managed	(223		)	267		(4,323		)	1,587
Net realized gains (losses) and change in fair value of funds held - directly managed	$	(2,309	)	$	4,656	$	(48,279	)	$	26,674

Fair Value Measurements

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

FAIR VALUE MEASUREMENTS

7. FAIR VALUE MEASUREMENTS

Fair Value Hierarchy

Fair value is defined as the price at which to sell an asset or transfer a liability (i.e. the "exit price") in an orderly transaction between market participants. We use a fair value hierarchy that gives the highest priority to quoted prices in active markets and the lowest priority to unobservable data. The hierarchy is broken down into three levels as follows:


•	Level 1 - Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access. Valuation adjustments and block discounts are not applied to Level 1 instruments.


•	Level 2 - Valuations based on quoted prices in active markets for similar assets or liabilities, quoted prices for identical assets or liabilities in inactive markets, or for which significant inputs are observable (e.g. interest rates, yield curves, prepayment speeds, default rates, loss severities, etc.) or can be corroborated by observable market data.


•	Level 3 - Valuations based on unobservable inputs where there is little or no market activity. Unadjusted third party pricing sources or management's assumptions and internal valuation models may be used to determine the fair values.

In addition, certain of our other investments are measured at fair value using net asset value ("NAV") per share (or its equivalent) as a practical expedient and have not been classified within the fair value hierarchy above. We have categorized our investments that are recorded at fair value on a recurring basis among levels based on the observability of inputs, or at fair value using NAV per share (or its equivalent) as follows:



	September 30, 2018
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value Based on NAV as Practical Expedient		Total Fair Value
Investments:
Fixed maturity investments:
U.S. government and agency	$	—	$	493,778	$	—	$	—	$	493,778
Non-U.S. government	—		1,093,768		—		—		1,093,768
Corporate	—		3,763,158		23,379		—		3,786,537
Municipal	—		79,966		—		—		79,966
Residential mortgage-backed	—		273,705		1,795		—		275,500
Commercial mortgage-backed	—		402,192		9,383		—		411,575
Asset-backed	—		535,578		31,722		—		567,300
	$	—	$	6,642,145	$	66,279	$	—	$	6,708,424
Equities:
Equities — U.S.	$	70,720	$	29	$	2,016	$	—	$	72,765
Equities — International	53,541		2,296		1,712		—		57,549
	$	124,261	$	2,325	$	3,728	$	—	$	130,314
Other investments:
Private equities and private equity funds	$	—	$	—	$	—	$	256,618	$	256,618
Fixed income funds	—		327,375		—		55,953		383,328
Hedge funds	—		—		—		879,571		879,571
Equity funds	—		117,337		—		264,646		381,983
CLO equities	—		—		48,368		—		48,368
CLO equity fund	—		—		—		41,501		41,501
Private credit funds	—		—		—		39,751		39,751
Call options on equities	—		4,590		—		—		4,590
Other	—		—		313		407		720
	$	—	$	449,302	$	48,681	$	1,538,447	$	2,036,430
Total Investments	$	124,261	$	7,093,772	$	118,688	$	1,538,447	$	8,875,168
Funds Held - Directly Managed:
U.S. government and agency	$	—	$	98,928	$	—	$	—	$	98,928
Non-U.S. government	—		22,610		—		—		22,610
Corporate	—		641,460		—		—		641,460
Municipal	—		53,679		—		—		53,679
Residential mortgage-backed	—		70,196		—		—		70,196
Commercial mortgage-backed	—		220,077		—		—		220,077
Asset-backed	—		95,743		—		—		95,743
Other assets	—		14,489		—		—		14,489
	$	—	$	1,217,182	$	—	$	—	$	1,217,182

Reinsurance balances recoverable:	$	—	$	—	$	792,553	$	—	$	792,553

Other Assets:
Derivative Instruments	$	—	$	1,197	$	—	$	—	$	1,197
	$	—	$	1,197	$	—	$	—	$	1,197

Losses and LAE:	$	—	$	—	$	3,019,721	$	—	$	3,019,721

Other Liabilities:
Derivative Instruments	$	—	$	5,775	$	—	$	—	$	5,775
	$	—	$	5,775	$	—	$	—	$	5,775



	December 31, 2017
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value Based on NAV as Practical Expedient		Total Fair Value
Investments:
Fixed maturity investments:
U.S. government and agency	$	—	$	558,223	$	—	$	—	$	558,223
Non-U.S. government	—		692,569		—		—		692,569
Corporate	—		3,411,003		67,178		—		3,478,181
Municipal	—		105,357		—		—		105,357
Residential mortgage-backed	—		285,664		3,080		—		288,744
Commercial mortgage-backed	—		400,054		21,494		—		421,548
Asset-backed	—		514,055		27,892		—		541,947
	$	—	$	5,966,925	$	119,644	$	—	$	6,086,569
Equities:
Equities — U.S.	$	103,652	$	2,711	$	—	$	—	$	106,363
Equities — International	—		240		—		—		240
	$	103,652	$	2,951	$	—	$	—	$	106,603
Other investments:
Private equities and private equity funds	$	—	$	—	$	—	$	289,556	$	289,556
Fixed income funds	—		202,570		—		27,429		229,999
Hedge funds	—		—		—		63,773		63,773
Equity funds	—		121,046		—		128,429		249,475
CLO equities	—		—		56,765		—		56,765
CLO equity funds	—		—		—		12,840		12,840
Private credit funds	—		—		—		10,156		10,156
Other	—		—		314		514		828
	$	—	$	323,616	$	57,079	$	532,697	$	913,392
Total Investments	$	103,652	$	6,293,492	$	176,723	$	532,697	$	7,106,564
Funds Held - Directly Managed:
U.S. government and agency	$	—	$	69,850	$	—	$	—	$	69,850
Non-U.S. government	—		2,926		—		—		2,926
Corporate	—		695,490		—		—		695,490
Municipal	—		58,930		—		—		58,930
Residential mortgage-backed	—		29,439		—		—		29,439
Commercial mortgage-backed	—		211,186		—		—		211,186
Asset-backed	—		97,565		—		—		97,565
Other assets	—		14,554		—		—		14,554
	$	—	$	1,179,940	$	—	$	—	$	1,179,940

Reinsurance balances recoverable:	$	—	$	—	$	542,224	$	—	$	542,224

Other Assets:
Derivative Instruments	$	—	$	319	$	—	$	—	$	319
	$	—	$	319	$	—	$	—	$	319

Losses and LAE:	$	—	$	—	$	1,794,669	$	—	$	1,794,669

Other Liabilities:
Derivative Instruments	$	—	$	7,246	$	—	$	—	$	7,246
	$	—	$	7,246	$	—	$	—	$	7,246

Valuation Methodologies of Financial Instruments Measured at Fair Value

Fixed Maturity Investments and Funds Held - Directly Managed

The fair values for all securities in the fixed maturity investments and funds held - directly managed portfolios are independently provided by the investment accounting service providers, investment managers and investment custodians, each of which utilize internationally recognized independent pricing services. We record the unadjusted price provided by the investment accounting service providers, investment managers or investment custodians and validate this price through a process that includes, but is not limited to: (i) comparison of prices against alternative pricing sources; (ii) quantitative analysis (e.g. comparing the quarterly return for each managed portfolio to its target benchmark); (iii) evaluation of methodologies used by external parties to estimate fair value, including a review of the inputs used for pricing; and (iv) comparing the price to our knowledge of the current investment market. Our internal price validation procedures and review of fair value methodology documentation provided by independent pricing services have not historically resulted in adjustment in the prices obtained from the pricing service.

The independent pricing services used by the investment accounting service providers, investment managers and investment custodians obtain actual transaction prices for securities that have quoted prices in active markets. Where we utilize single unadjusted broker-dealer quotes, they are generally provided by market makers or broker-dealers who are recognized as market participants in the markets in which they are providing the quotes. For determining the fair value of securities that are not actively traded, in general, pricing services use "matrix pricing" in which the independent pricing service uses observable market inputs including, but not limited to, reported trades, benchmark yields, broker-dealer quotes, interest rates, prepayment speeds, default rates and such other inputs as are available from market sources to determine a reasonable fair value. In addition, pricing services use valuation models, using observable data, such as an Option Adjusted Spread model, to develop prepayment and interest rate scenarios. The Option Adjusted Spread model is commonly used to estimate fair value for securities such as mortgage-backed and asset-backed securities.

The following describes the techniques generally used to determine the fair value of our fixed maturity investments by asset class, including the investments underlying the funds held - directly managed.

•

U.S. government and agency securities consist of securities issued by the U.S. Treasury and mortgage pass-through agencies such as the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation and other agencies. Non-U.S. government securities consist of bonds issued by non-U.S. governments and agencies along with supranational organizations. The significant inputs used to determine the fair value of these securities include the spread above the risk-free yield curve, reported trades and broker-dealer quotes. These are considered to be observable market inputs and, therefore, the fair values of these securities are classified as Level 2.

•

Corporate securities consist primarily of investment-grade debt of a wide variety of corporate issuers and industries. The fair values of these securities are determined using the spread above the risk-free yield curve, reported trades, broker-dealer quotes, benchmark yields, and industry and market indicators. These are considered observable market inputs and, therefore, the fair values of these securities are classified as Level 2. Where pricing is unavailable from pricing services, such as in periods of low trading activity or when transactions are not orderly, we obtain non-binding quotes from broker-dealers. Where significant inputs are unable to be corroborated with market observable information, we classify the securities as Level 3.


•	Municipal securities consist primarily of bonds issued by U.S.-domiciled state and municipal entities. The fair values of these securities are determined using the spread above the risk-free yield curve, reported trades, broker-dealer quotes and benchmark yields. These are considered observable market inputs and, therefore, the fair values of these securities are classified as Level 2.

•

Asset-backed securities consist primarily of investment-grade bonds backed by pools of loans with a variety of underlying collateral. Residential and commercial mortgage-backed securities include both agency and non-agency originated securities. Where pricing is unavailable from pricing services, we obtain non-binding quotes from broker-dealers. This is generally the case when there is a low volume of trading activity and current transactions are not orderly. The significant inputs used to determine the fair value of these securities include the spread above the risk-free yield curve, reported trades, benchmark yields, prepayment speeds and default rates. The fair values of these securities are classified as Level 2 if the significant inputs are market observable. Where significant inputs are unable to be corroborated with market observable information, we classify the securities as Level 3.

Equities

Our investments in equities are predominantly traded on the major exchanges and are primarily managed by our external advisors. We use an internationally recognized pricing service to estimate the fair value of our equities. Our equities are widely diversified and there is no significant concentration in any specific industry.

We have categorized our publicly quoted equity securities as Level 1 within the fair value hierarchy because their fair values are based on unadjusted quoted prices for identical securities in active markets. Other equity securities have been categorized as either Level 2 if their fair values are based on observable market data or Level 3 if their fair values are based on unobservable inputs where there is minimal or no market activity.

Other investments, at fair value

We have ongoing due diligence processes with respect to the other investments carried at fair value in which we invest and their managers. These processes are designed to assist us in assessing the quality of information provided by, or on behalf of, each fund and in determining whether such information continues to be reliable or whether further review is warranted. Certain funds do not provide full transparency of their underlying holdings; however, we obtain the audited financial statements for funds annually, and regularly review and discuss the fund performance with the fund managers to corroborate the reasonableness of the reported net asset values ("NAV").

The use of NAV as an estimate of the fair value for investments in certain entities that calculate NAV is a permitted practical expedient. Due to the time lag in the NAV reported by certain fund managers we adjust the valuation for capital calls and distributions. Other investments measured at fair value using NAV as a practical expedient have not been classified in the fair value hierarchy. Other investments for which we do not use NAV as a practical expedient have been valued using prices from independent pricing services, investment managers and broker-dealers.

The following describes the techniques generally used to determine the fair value of our other investments.


•	For our investments in private equities and private equity funds, we measure fair value by obtaining the most recently available NAV from the external fund manager or third-party administrator. The fair values of these investments are measured using the NAV as a practical expedient and therefore have not been categorized within the fair value hierarchy.

•

Our investments in fixed income funds and equity funds are valued based on a combination of prices from independent pricing services, external fund managers or third-party administrators. For the publicly available prices we have classified the investments as Level 2. For the non-publicly available prices we are using NAV as a practical expedient and therefore these have not been categorized within the fair value hierarchy.


•	For our investments in hedge funds, we measure fair value by obtaining the most recently available NAV as advised by the external fund manager or third-party administrator. The fair values of these investments are measured using the NAV as a practical expedient and therefore have not been categorized within the fair value hierarchy.

•

We measure the fair value of our direct investment in CLO equities based on valuations provided by our external CLO equity manager. If the investment does not involve an external CLO equity manager, the fair value of the investment is valued based on valuations provided by the broker or lead underwriter of the investment (the "broker"). Our CLO equity investments have been classified as Level 3 due to the use of unobservable inputs in the valuation and the limited number of relevant trades in secondary markets.

In providing valuations, the CLO equity manager and brokers use observable and unobservable inputs. Of the significant unobservable market inputs used, the default and loss severity rates involve the most judgment and create the most sensitivity. A significant increase or decrease in either of these significant inputs in isolation would result in lower or higher fair value estimates for direct investments in CLO equities and, in general, a change in default rate assumptions will be accompanied by a directionally similar change in loss severity rate assumptions. Collateral spreads and estimated maturity dates are less subjective inputs because they are based on the historical average of actual spreads and the weighted-average life of the current underlying portfolios, respectively. A significant increase or decrease in either of these significant inputs in isolation would result in higher or lower fair value estimates for direct investments in CLO equities. In general, these inputs have no significant interrelationship with each other or with default and loss severity rates.

On a quarterly basis, we receive the valuation from the external CLO manager and brokers and then review the underlying cash flows and key assumptions used by them. We review and update the significant unobservable inputs based on information obtained from secondary markets. These inputs are our responsibility and we assess the reasonableness of the inputs (and if necessary, update the inputs) through communicating with industry participants, monitoring of the transactions in which we participate (for example, to evaluate default and loss severity rate trends), and reviewing market conditions, historical results, and emerging trends that may impact future cash flows.

If valuations from the external CLO equity manager or brokers are not available, we use an income approach based on certain observable and unobservable inputs to value these investments. An income approach is also used to corroborate the reasonableness of the valuations provided by the external manager and brokers. Where an income approach is followed, the valuation is based on available trade information, such as expected cash flows and market assumptions on default and loss severity rates. Other inputs used in the valuation process include asset spreads, loan prepayment speeds, collateral spreads and estimated maturity dates.


•	For our investments in CLO equity funds, we measure fair value by obtaining the most recently available NAV as advised by the external fund manager or third party administrator. The fair values of these investments are measured using the NAV as a practical expedient and therefore have not been categorized within the fair value hierarchy.


•	For our investments in private credit funds, we measure fair value by obtaining the most recently available NAV from the external fund manager or third-party administrator. The fair values of these investments are measured using the NAV as a practical expedient and therefore have not been categorized within the fair value hierarchy.


•	For our investments in call options on publicly traded equities, we measure fair value by obtaining the latest option price as of our reporting date. These are classified as Level 2.

Insurance Contracts - Fair Value Option

The Company uses an internal model to calculate the fair value of the liability for losses and loss adjustment expenses and reinsurance balances recoverable asset for certain retroactive reinsurance contracts where we have elected the fair value option in our Non-life Run-off segment. The fair value was calculated as the aggregate of discounted cash flows plus a risk margin. The discounted cash flow approach uses (i) estimated nominal cash flows based upon an appropriate payment pattern developed in accordance with standard actuarial techniques and (ii) a discount rate based upon a high quality rated corporate bond plus a credit spread for non-performance risk. The model uses corporate bond rates across the yield curve depending on the estimated timing of the future cash flows and specific to the currency of the risk. The risk margin was calculated using the present value of the cost of capital. The cost of capital approach uses (i) projected capital requirements, (ii) multiplied by the risk cost of capital representing the return required for non-hedgeable risk based upon the weighted average cost of capital less investment income, and (iii) discounted using the weighted average cost of capital.

Derivative Instruments

The fair values of our foreign currency exchange contracts, as described in Note 8 - "Derivative and Hedging Instruments" are classified as Level 2. The fair values are based upon prices in active markets for identical contracts.

Level 3 Measurements and Changes in Leveling

Transfers into or out of levels are recorded at their fair values as of the end of the reporting period, consistent with the date of determination of fair value.

Investments

The following tables present a reconciliation of the beginning and ending balances for all investments measured at fair value on a recurring basis using Level 3 inputs during the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended September 30, 2018
	Corporate			Residential mortgage-backed		Commercial mortgage-backed			Asset-backed			Equities		Other Investments			Total
Beginning fair value	$	27,823		$	—	$	15,326		$	46,608		$	2,016	$	54,154		$	145,927
Purchases	205			—		1,599			16,376			—		—			18,180
Sales	(3,731		)	—		(3,271		)	(28,182		)	—		—			(35,184		)
Total realized and unrealized gains (losses)	92			1		(726		)	(346		)	—		(5,473		)	(6,452		)
Transfer into Level 3 from Level 2	292			1,794		—			(1		)	1,712		—			3,797
Transfer out of Level 3 into Level 2	(1,302		)	—		(3,545		)	(2,733		)	—		—			(7,580		)
Ending fair value	$	23,379		$	1,795	$	9,383		$	31,722		$	3,728	$	48,681		$	118,688



	Three Months Ended September 30, 2017
	Corporate			Residential mortgage-backed			Commercial mortgage-backed			Asset-backed			Equities		Other Investments			Total
Beginning fair value	$	54,356		$	693		$	22,865		$	40,433		$	—	$	57,119		$	175,466
Purchases	2,510			—			11,274			4,350			—		143			18,277
Sales	(3,350		)	(33		)	(602		)	(1,184		)	—		—			(5,169		)
Total realized and unrealized gains (losses)	(834		)	3			(398		)	(384		)	—		(1,538		)	(3,151		)
Transfer into Level 3 from Level 2	5,670			—			616			4,002			—		—			10,288
Transfer out of Level 3 into Level 2	(5,193		)	(663		)	(1,619		)	(10,528		)	—		—			(18,003		)
Ending fair value	$	53,159		$	—		$	32,136		$	36,689		$	—	$	55,724		$	177,708



	Nine Months Ended September 30, 2018
	Corporate			Residential mortgage-backed			Commercial mortgage-backed			Asset-backed			Equities		Other Investments			Total
Beginning fair value	$	67,178		$	3,080		$	21,494		$	27,892		$	—	$	57,079		$	176,723
Purchases	12,008			—			3,402			45,967			2,000		752			64,129
Sales	(64,641		)	(1,184		)	(4,998		)	(31,994		)	—		(600		)	(103,417		)
Total realized and unrealized gains (losses)	29			(32		)	(674		)	(417		)	16		(8,550		)	(9,628		)
Transfer into Level 3 from Level 2	15,551			1,794			4,897			2,078			1,712		—			26,032
Transfer out of Level 3 into Level 2	(6,746		)	(1,863		)	(14,738		)	(11,804		)	—		—			(35,151		)
Ending fair value	$	23,379		$	1,795		$	9,383		$	31,722		$	3,728	$	48,681		$	118,688



	Nine Months Ended September 30, 2017
	Corporate			Residential mortgage-backed			Commercial mortgage-backed			Asset-backed			Equities		Other Investments			Total
Beginning fair value	$	74,534		$	—		$	12,213		$	14,692		$	—	$	76,878		$	178,317
Purchases	18,078			711			21,621			5,730			—		435			46,575
Sales	(28,467		)	(38		)	(1,336		)	(8,545		)	—		—			(38,386		)
Total realized and unrealized losses	(184		)	(10		)	(67		)	(175		)	—		(9,239		)	(9,675		)
Transfer into Level 3 from Level 2	10,615			—			18,532			53,338			—		—			82,485
Transfer out of Level 3 into Level 2	(21,417		)	(663		)	(18,827		)	(28,351		)	—		(12,350		)	(81,608		)
Ending fair value	$	53,159		$	—		$	32,136		$	36,689		$	—	$	55,724		$	177,708

Net realized and unrealized gains related to Level 3 assets in the tables above are included in net realized and unrealized gains (losses) in our unaudited condensed consolidated statements of earnings.

The securities transferred from Level 2 to Level 3 were transferred due to insufficient market observable inputs for the valuation of the specific assets. The transfers from Level 3 to Level 2 were based upon us obtaining market observable information regarding the valuations of the specific assets.

Insurance Contracts - Fair Value Option

The following tables present a reconciliation of the beginning and ending balances for all insurance contracts measured at fair value on a recurring basis using Level 3 inputs during the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended
	September 30, 2018						September 30, 2017
	Liability for losses and LAE			Reinsurance balances recoverable			Liability for losses and LAE			Reinsurance balances recoverable
Beginning fair value	$	3,221,366		$	837,373		$	1,892,297		$	554,759
Assumed business	—			—			—			—
Changes in nominal amounts:
Net incurred losses and LAE	(19,973		)	1,085			(22,711		)	(3,181		)
Paid losses	(149,132		)	(41,819		)	(36,466		)	(9,453		)
Changes in fair value:
Discounted cash flows	(2,811		)	483			(6,826		)	730
Risk margin	(7,762		)	(1,949		)	(3,845		)	(897		)
Effect of exchange rate movements	(21,967		)	(2,620		)	32,803			3,790
Ending fair value	$	3,019,721		$	792,553		$	1,855,252		$	545,748



	Nine Months Ended
	September 30, 2018						September 30, 2017
	Liability for losses and LAE			Reinsurance balances recoverable			Liability for losses and LAE			Reinsurance balances recoverable
Beginning fair value	$	1,794,669		$	542,224		$	—		$	—
Assumed business	1,890,061			372,780			1,966,843			565,824
Changes in nominal amounts:
Net incurred losses and LAE	(75,169		)	3,469			(55,356		)	(5,276		)
Paid losses	(453,180		)	(95,354		)	(136,519		)	(30,947		)
Changes in fair value:
Discounted cash flows	(23,674		)	(13,399		)	10,187			9,143
Risk margin	(26,508		)	(4,668		)	(12,897		)	(2,599		)
Effect of exchange rate movements	(86,478		)	(12,499		)	82,994			9,603
Ending fair value	$	3,019,721		$	792,553		$	1,855,252		$	545,748

Changes in fair value related to Level 3 assets and liabilities in the tables above are included in net incurred losses and LAE in our unaudited condensed consolidated statements of earnings.

Below is a summary of the quantitative information regarding the significant observable and unobservable inputs used in the internal model to determine fair value on a recurring basis as at September 30, 2018 and December 31, 2017:



		September 30, 2018	December 31, 2017
Valuation Technique	Unobservable (U) and Observable (O) Inputs	Weighted Average
Internal model	Corporate bond yield (O)	A rated	A rated
Internal model	Credit spread for non-performance risk (U)	0.2%	0.2%
Internal model	Risk cost of capital (U)	5.0%	5.0%
Internal model	Weighted average cost of capital (U)	8.5%	8.5%
Internal model	Duration - liability (U)	8.05 years	11.41 years
Internal model	Duration - reinsurance balances recoverable (U)	9.03 years	11.66 years

The fair value of the liability for losses and LAE and reinsurance balances recoverable may increase or decrease due to changes in the corporate bond rate, the credit spread for non-performance risk, the risk cost of capital, the weighted average cost of capital and the estimated payment pattern as described below:

•

An increase in the corporate bond rate or credit spread for non-performance risk would result in a decrease in the fair value of the liability for losses and LAE and reinsurance balances recoverable. Conversely, a decrease in the corporate bond rate or credit spread for non-performance risk would result in an increase in the fair value of the liability for losses and LAE and reinsurance balances recoverable.


•	An increase in the weighted average cost of capital would result in an increase in the fair value of the liability for losses and LAE and reinsurance balances recoverable. Conversely, a decrease in the weighted average cost of capital would result in a decrease in the fair value of the liability for losses and LAE and reinsurance balances recoverable.


•	An increase in the risk cost of capital would result in an increase in the fair value of the liability for losses and LAE and reinsurance balances recoverable. Conversely, a decrease in the risk cost of capital would result in a decrease in the fair value of the liability for losses and LAE and reinsurance balances recoverable.


•	An acceleration of the estimated payment pattern would result in an increase in the fair value of the liability for losses and LAE and reinsurance balances recoverable. Conversely, a deceleration of the estimated payment pattern would result in a decrease in the fair value of the liability for losses and LAE and reinsurance balances recoverable.

In addition, the estimate of the capital required to support the liabilities is based upon current industry standards for capital adequacy. If the required capital per unit of risk increases then the fair value of the liability for losses and LAE and reinsurance balances recoverable would increase. Conversely, a decrease in required capital would result in a decrease in the fair value of the liability for losses and LAE and reinsurance balances recoverable.

Disclosure of Fair Values for Financial Instruments Carried at Cost

During the three months ended June 30, 2018, we sold our investments in life settlement contracts, which were carried at cost. As at December 31, 2017, investments in life settlement contracts were carried at cost of $125.6 million, and their fair values were $131.9 million.

The fair value of investments in life settlement contracts was determined using a discounted cash flow methodology that utilizes unobservable inputs. Due to the individual nature of each investment in life settlement contracts and the illiquidity of the existing market, significant inputs to the fair value included our estimates of premiums necessary to keep the policies in-force, and our assumptions for mortality and discount rates. Our mortality assumptions were based on a combination of medical underwriting information obtained from a third-party underwriter for each referenced life and internal proprietary mortality studies of older aged U.S. insured lives. These assumptions were used to develop an estimate of future net cash flows that, after discounting, was intended to be reflective of the asset's value in the life settlement market.

As at September 30, 2018, our 4.5% Senior Notes due 2022 were carried at amortized cost of $348.0 million while the fair value based on observable market pricing from a third party pricing service was $351.5 million. The Senior Notes are classified as Level 2.

Disclosure of fair value of amounts relating to insurance contracts is not required, except those for which we elected the fair value option, as described above. Our remaining assets and liabilities were generally carried at cost or amortized cost, which due to their short-term nature approximates fair value as of September 30, 2018 and December 31, 2017.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Derivative and Hedging Instruments

9 Months Ended

Sep. 30, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

DERIVATIVE AND HEDGING INSTRUMENTS

8. DERIVATIVE AND HEDGING INSTRUMENTS

Foreign Currency Hedging of Net Investments in Foreign Operations

We use foreign currency forward exchange rate contracts in qualifying hedging relationships to hedge the foreign currency exchange rate risk associated with certain of our net investments in foreign operations. At September 30, 2018 and December 31, 2017, we had forward currency contracts in place, which we had designated as hedges of our net investments in foreign operations.

The following table presents the gross notional amounts and estimated fair values recorded within other assets and liabilities related to our qualifying foreign currency forward exchange rate contracts as at September 30, 2018 and December 31, 2017.



	September 30, 2018						December 31, 2017
			Fair Value						Fair Value
	Gross Notional Amount		Assets		Liabilities		Gross Notional Amount		Assets		Liabilities
Foreign exchange forward - AUD	$	43,410	$	237	$	—	$	32,810	$	—	$	965
Foreign exchange forward - EUR	69,800		175		—		—		—		—
Foreign exchange forward - CAD	—		—		—		27,141		11		512
Total qualifying hedges	$	113,210	$	412	$	—	$	59,951	$	11	$	1,477

The Canadian Dollar ("CAD") foreign currency contract that we had in place to hedge the net investment in our CAD denominated operations was discontinued effective December 31, 2017 following the disposal of those operations.

The following table presents the amounts of the net gains and losses deferred in the currency translation adjustment ("CTA") account, which is a component of accumulated other comprehensive income (loss) ("AOCI"), in shareholders' equity, relating to our foreign currency forward exchange rate contracts for the three and nine months ended September 30, 2018 and 2017.



	Amount of Gains (Losses) Deferred in AOCI
	Three Months Ended					Nine Months Ended
	September 30,					September 30,
	2018		2017			2018		2017
Foreign exchange forward - AUD	$	678	$	(1,243	)	$	2,286	$	(1,805	)
Foreign exchange forward - EUR	52		—			52		—
Foreign exchange forward - CAD	—		(1,038		)	—		(1,154		)
Net gains (losses) on qualifying derivative hedges	$	730	$	(2,281	)	$	2,338	$	(2,959	)

Non-derivative Hedging Instruments of Net Investments in Foreign Operations

As at September 30, 2018 and December 31, 2017, there were borrowings of €nil and €50.0 million ($60.1 million), respectively, under our revolving credit facilities in effect as of such dates that were designated as non-derivative hedges of our net investment in certain subsidiaries whose functional currency is denominated in Euros. Our borrowings under our previous revolving credit facility that we had designated as non-derivative hedges of our net investment in certain subsidiaries whose functional currency is denominated in Euros were repaid in full during the three months ended September 30, 2018 and replaced by a Euro-denominated foreign currency forward exchange rate contract in a qualifying hedging arrangement. The following table presents the amounts of the net gains and losses deferred in the CTA account in AOCI relating to these qualifying Euro-loan non-derivative hedging instruments for the three and nine months ended September 30, 2018 and 2017.



	Amount of Gains (Losses) Deferred in AOCI
	Three Months Ended					Nine Months Ended
	September 30,					September 30,
	2018		2017			2018		2017
Net gains (losses) on qualifying non-derivative hedges	$	696	$	(1,785	)	$	3,144	$	(8,280	)

Derivatives Not Designated or Not Qualifying as Hedging Instruments

From time to time, we may also utilize foreign currency forward contracts as part of our overall foreign currency risk management strategy or to obtain exposure to a particular financial market, as well as for yield enhancement in non-qualifying hedging relationships. We may also utilize equity call option instruments either to obtain exposure to a particular equity instrument or for yield enhancement in non-qualifying hedging relationships.

Foreign Currency Forward Contracts

The following table presents the gross notional amounts and the estimated fair values recorded within other assets and liabilities related to our non-qualifying foreign currency forward exchange rate hedging relationships as at September 30, 2018 and December 31, 2017.



	September 30, 2018						December 31, 2017
			Fair Value						Fair Value
	Gross Notional Amount		Assets		Liabilities		Gross Notional Amount		Assets		Liabilities
Foreign exchange forward - AUD	$	35,090	$	236	$	—	$	57,028	$	—	$	1,002
Foreign exchange forward - CAD	91,577		42		—		—		—		—
Foreign exchange forward - EUR	29,035		71		500		19,235		46		455
Foreign exchange forward - GBP	251,059		436		5,275		207,323		262		4,312
Total non-qualifying hedges	$	406,761	$	785	$	5,775	$	283,586	$	308	$	5,769

The following table presents the amounts of the net gains (losses) included in earnings related to our non-qualifying foreign currency forward exchange rate contracts during the three and nine months ended September 30, 2018 and 2017.



	Gains (Losses) on non-qualifying-hedges included in net earnings
	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018		2017
Foreign exchange forward - AUD	$	957		$	—		$	3,453	$	—
Foreign exchange forward - CAD	(1,782		)	—			5,465		—
Foreign exchange forward - EUR	458			—			1,815		(562		)
Foreign exchange forward - GBP	4,154			(3,831		)	8,389		$	(4,701	)
Net gains (losses) on non-qualifying hedges	$	3,787		$	(3,831	)	$	19,122	$	(5,263	)

Investments in Call Options on Equities

We use equity call option instruments either to obtain exposure to a particular equity instrument or for yield enhancement, in non-qualifying hedging relationships.

During the nine months ended September 30, 2018, we purchased call options on equities at a cost of $10.0 million and recorded unrealized losses in net earnings of $0.4 million and $5.4 million on the call options for the three and nine months ended September 30, 2018, respectively. We did not have any equity derivative instruments during the nine months ended September 30, 2017 or as at December 31, 2017.

Reinsurance Balances Recoverable

9 Months Ended

Sep. 30, 2018

Insurance [Abstract]

REINSURANCE BALANCES RECOVERABLE

9. REINSURANCE BALANCES RECOVERABLE

The following tables provide the total reinsurance balances recoverable as at September 30, 2018 and December 31, 2017:



	September 30, 2018
	Non-life Run-off			Atrium			StarStone			Total
Recoverable from reinsurers on unpaid:
Outstanding losses	$	932,142		$	13,051		$	214,963		$	1,160,156
IBNR	664,873			31,445			175,302			871,620
Fair value adjustments	(14,489		)	886			(1,550		)	(15,153		)
Fair value adjustments - fair value option	(170,436		)	—			—			(170,436		)
Total reinsurance reserves recoverable	1,412,090			45,382			388,715			1,846,187
Paid losses recoverable	108,218			(1,808		)	22,959			129,369
	$	1,520,308		$	43,574		$	411,674		$	1,975,556
Reconciliation to Consolidated Balance Sheet:
Reinsurance balances recoverable	$	727,755		$	43,574		$	411,674		$	1,183,003
Reinsurance balances recoverable - fair value option	792,553			—			—			792,553
Total	$	1,520,308		$	43,574		$	411,674		$	1,975,556



	December 31, 2017
	Non-life Run-off			Atrium			StarStone			Other		Total
Recoverable from reinsurers on unpaid:
Outstanding losses	$	932,284		$	7,472		$	211,650		$	16	$	1,151,422
IBNR	590,154			31,476			242,620			—		864,250
Fair value adjustments	(12,970		)	1,583			(2,253		)	—		(13,640		)
Fair value adjustments - fair value option	(131,983		)	—			—			—		(131,983		)
Total reinsurance reserves recoverable	1,377,485			40,531			452,017			16		1,870,049
Paid losses recoverable	128,253			(451		)	23,179			—		150,981
	$	1,505,738		$	40,080		$	475,196		$	16	$	2,021,030
Reconciliation to Consolidated Balance Sheet:
Reinsurance balances recoverable	$	963,514		$	40,080		$	475,196		$	16	$	1,478,806
Reinsurance balances recoverable - fair value option	542,224			—			—			—		542,224
Total	$	1,505,738		$	40,080		$	475,196		$	16	$	2,021,030

Our insurance and reinsurance run-off subsidiaries and assumed portfolios, prior to acquisition, used retrocessional agreements to reduce their exposure to the risk of insurance and reinsurance assumed. On an annual basis, both Atrium and StarStone purchase a tailored outwards reinsurance program designed to manage their risk profiles. The majority of Atrium’s and StarStone's third-party reinsurance cover is with highly rated reinsurers or is collateralized by pledged assets or letters of credit.

The fair value adjustments, determined on acquisition of insurance and reinsurance subsidiaries, are based on the estimated timing of loss and LAE recoveries and an assumed interest rate equivalent to a risk free rate for securities with similar duration to the acquired reinsurance balances recoverables plus a spread for credit risk, and are amortized over the estimated recovery period, as adjusted for accelerations in timing of payments as a result of commutation settlements. The determination of the fair value adjustments on the retroactive reinsurance contracts for which we have elected the fair value option is described in Note 7 - "Fair Value Measurements".

As at September 30, 2018 and December 31, 2017, we had reinsurance balances recoverable of $1,975.6 million and $2,021.0 million, respectively. The decrease of $45.5 million in reinsurance balances recoverable was primarily a result of KaylaRe becoming a wholly-owned subsidiary and reserve reductions in our Non-life Run-off segment and cash collections and commutations made during the nine months ended September 30, 2018, partially offset by the Neon and Novae reinsurance transactions, which closed during the first quarter of 2018, as well as reserve increases in StarStone.

Top Ten Reinsurers



	September 30, 2018
	Non-life Run-off		Atrium		StarStone		Total		% of Total
Top ten reinsurers	$	1,167,500	$	28,669	$	239,686	$	1,435,855	72.7	%
Other reinsurers > $1 million	335,939		14,232		168,194		518,365		26.2	%
Other reinsurers < $1 million	16,869		673		3,794		21,336		1.1	%
Total	$	1,520,308	$	43,574	$	411,674	$	1,975,556	100.0	%



	December 31, 2017
	Non-life Run-off		Atrium		StarStone		Other		Total		% of Total
Top ten reinsurers	$	1,166,057	$	22,422	$	328,257	$	—	$	1,516,736	75.0	%
Other reinsurers > $1 million	322,722		16,631		144,336		—		483,689		24.0	%
Other reinsurers < $1 million	16,959		1,027		2,603		16		20,605		1.0	%
Total	$	1,505,738	$	40,080	$	475,196	$	16	$	2,021,030	100.0	%



	September 30, 2018		December 31, 2017
Information regarding top ten reinsurers:
Number of top 10 reinsurers rated A- or better	7		6
Number of top 10 non-rated reinsurers ⁽¹⁾	3		4

Top 10 rated A- or better reinsurers recoverables	$	1,116,423	$	829,164
Top 10 collaterized non-rated reinsurers recoverables ⁽¹⁾	$	319,432	$	687,572
	$	1,435,855	$	1,516,736

Single reinsurers that represent 10% or more of total reinsurance balance recoverables as at September 30, 2018:

Hannover Ruck SE ⁽²⁾	$	327,287	$	320,047
Lloyd's Syndicates ⁽³⁾	$	303,598	$	193,838

⁽¹⁾For the three non-rated reinsurers at as September 30, 2018 and four non-rated reinsurers as at December 31, 2017, we hold security in the form of pledged assets in trust or letters of credit issued to us in the full amount of the recoverable.

⁽²⁾ Hannover Ruck SE is rated AA- by Standard & Poor’s and A+ by A.M. Best.

⁽³⁾ Lloyd's Syndicates are rated A+ by Standard & Poor's and A by A.M. Best.

Provisions for Uncollectible Reinsurance Balances Recoverable

We evaluate and monitor concentration of credit risk among our reinsurers, and provisions are made for amounts considered potentially uncollectible.

The following table shows our reinsurance balances recoverable by rating of reinsurer and our provisions for uncollectible reinsurance balances recoverable ("provisions for bad debt") as at September 30, 2018 and December 31, 2017. The provisions for bad debt all relate to the Non-life Run-off segment.



	September 30, 2018								December 31, 2017
	Gross		Provisions for Bad Debt		Net		Provisions as a % of Gross		Gross		Provisions for Bad Debt		Net		Provisions as a % of Gross
Reinsurers rated A- or above	$	1,600,220	$	54,960	$	1,545,260	3.4	%	$	1,252,887	$	51,115	$	1,201,772	4.1	%
Reinsurers rated below A-, secured	397,775		—		397,775		—	%	771,097		—		771,097		—	%
Reinsurers rated below A-, unsecured	135,987		103,466		32,521		76.1	%	162,259		114,098		48,161		70.3	%
Total	$	2,133,982	$	158,426	$	1,975,556	7.4	%	$	2,186,243	$	165,213	$	2,021,030	7.6	%

12. PREMIUMS WRITTEN AND EARNED

The following table provides a summary of net premiums written and earned in our Non-life Run-off, Atrium and StarStone segments and Other activities for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended September 30,												Nine Months Ended September 30,
	2018						2017						2018						2017
	Premiums Written			Premiums Earned			Premiums Written			Premiums Earned			Premiums Written			Premiums Earned			Premiums Written			Premiums Earned
Non-life Run-off
Gross	$	9,912		$	17,746		$	11,751		$	9,345		$	16,354		$	54,044		$	13,956		$	15,353
Ceded	(5,134		)	(7,304		)	(284		)	(2,930		)	(13,137		)	(26,815		)	(503		)	(5,497		)
Net	$	4,778		$	10,442		$	11,467		$	6,415		$	3,217		$	27,229		$	13,453		$	9,856
Atrium
Gross	$	39,995		$	42,505		$	36,377		$	39,591		$	130,997		$	121,974		$	117,355		$	111,633
Ceded	(2,854		)	(5,528		)	(10,388		)	(6,818		)	(17,779		)	(15,252		)	(18,120		)	(14,260		)
Net	$	37,141		$	36,977		$	25,989		$	32,773		$	113,218		$	106,722		$	99,235		$	97,373
StarStone
Gross	$	282,525		$	281,467		$	200,007		$	217,833		$	888,867		$	761,694		$	651,107		$	636,137
Ceded	(62,799		)	(65,112		)	(102,958		)	(110,183		)	(269,339		)	(234,892		)	(319,658		)	(294,528		)
Net	$	219,726		$	216,355		$	97,049		$	107,650		$	619,528		$	526,802		$	331,449		$	341,609
Other
Gross	$	846		$	848		$	2,424		$	1,444		$	2,858		$	2,878		$	4,506		$	4,658
Ceded	(24		)	(25		)	(753		)	(257		)	13			(3		)	(860		)	(1,002		)
Net	$	822		$	823		$	1,671		$	1,187		$	2,871		$	2,875		$	3,646		$	3,656
Total
Gross	$	333,278		$	342,566		$	250,559		$	268,213		$	1,039,076		$	940,590		$	786,924		$	767,781
Ceded	(70,811		)	(77,969		)	(114,383		)	(120,188		)	(300,242		)	(276,962		)	(339,141		)	(315,287		)
Total	$	262,467		$	264,597		$	136,176		$	148,025		$	738,834		$	663,628		$	447,783		$	452,494

Losses and Loss Adjustment Expenses

9 Months Ended

Sep. 30, 2018

Insurance [Abstract]

LOSSES AND LOSS ADJUSTMENT EXPENSES

10. LOSSES AND LOSS ADJUSTMENT EXPENSES

The liability for losses and loss adjustment expenses ("LAE"), also referred to as loss reserves, represents our gross estimates before reinsurance for unpaid reported losses and includes losses that have been incurred but not reported ("IBNR") for our Non-life Run-off, Atrium and StarStone segments using a variety of actuarial methods. We recognize an asset for the portion of the liability that we expect to recover from reinsurers. LAE reserves include allocated loss adjustment expenses ("ALAE"), and unallocated loss adjustment expenses ("ULAE"). ALAE are linked to the settlement of an individual claim or loss, whereas ULAE are based on our estimates of future costs to administer the claims. IBNR represents reserves for loss and LAE that have been incurred but not yet reported to us. This includes amounts for unreported claims, development on known claims and reopened claims. Our loss reserves cover multiple lines of business, which include workers' compensation, general casualty, asbestos and environmental, marine, aviation and transit, construction defects and other non-life lines of business. Refer to Note 11 - "Losses and Loss Adjustment Expenses" to the consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2017 for more information on establishing the liability for losses and LAE.

The following table summarizes the liability for losses and LAE by segment as at September 30, 2018 and December 31, 2017:



	September 30, 2018
	Non-life Run-off			Atrium		StarStone			Total
Outstanding losses	$	3,998,430		$	83,138	$	714,231		$	4,795,799
IBNR	3,072,291			152,462		723,987			3,948,740
Fair value adjustments	(120,916		)	4,749		(381		)	(116,548		)
Fair value adjustments - fair value option	(457,215		)	—		—			(457,215		)
ULAE	340,165			2,418		22,374			364,957
Total	$	6,832,755		$	242,767	$	1,460,211		$	8,535,733

Reconciliation to Consolidated Balance Sheet:
Loss and loss adjustment expenses	$	3,813,034		$	242,767	$	1,460,211		$	5,516,012
Loss and loss adjustment expenses, at fair value	3,019,721			—		—			3,019,721
Total	$	6,832,755		$	242,767	$	1,460,211		$	8,535,733



	December 31, 2017
	Non-life Run-off			Atrium		StarStone			Total
Outstanding losses	$	3,185,703		$	78,363	$	590,977		$	3,855,043
IBNR	2,903,927			150,508		599,221			3,653,656
Fair value adjustments	(125,998		)	9,547		(555		)	(117,006		)
Fair value adjustments - fair value option	(314,748		)	—		—			(314,748		)
ULAE	300,588			2,455		18,100			321,143
Total	$	5,949,472		$	240,873	$	1,207,743		$	7,398,088

Reconciliation to Consolidated Balance Sheet:
Loss and loss adjustment expenses	$	4,154,803		$	240,873	$	1,207,743		$	5,603,419
Loss and loss adjustment expenses, at fair value	$	1,794,669		$	—	$	—		$	1,794,669
Total	$	5,949,472		$	240,873	$	1,207,743		$	7,398,088

The overall increase in the liability for losses and LAE between December 31, 2017 and September 30, 2018 was primarily attributable to the assumed reinsurance agreements with Zurich Australia, Neon, Novae and Coca-Cola in our Non-life Run-off segment, as described in Note 3 - "Significant New Business", and the acquisition of KaylaRe, as described in Note 2 - "Acquisitions".

The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended					Nine Months Ended
	September 30,					September 30,
	2018			2017		2018			2017
Balance as at beginning of period	$	8,608,387		$	7,641,384	$	7,398,088		$	5,987,867
Less: reinsurance reserves recoverable	1,866,969			1,923,962		1,870,033			1,388,193
Less: deferred charges on retroactive reinsurance	71,393			88,475		80,192			94,551
Net balance as at beginning of period	6,670,025			5,628,947		5,447,863			4,505,123
Net incurred losses and LAE:
Current period	219,050			147,846		468,064			314,791
Prior periods	(65,076		)	(72,134)		(201,737		)	(151,567		)
Total net incurred losses and LAE	153,974			75,712		266,327			163,224
Net paid losses:
Current period	(24,266		)	(15,928)		(62,843		)	(40,820		)
Prior periods	(296,709		)	(215,173)		(937,846		)	(670,117		)
Total net paid losses	(320,975		)	(231,101)		(1,000,689		)	(710,937		)
Effect of exchange rate movement	(26,825		)	55,712		(108,659		)	139,448
Acquired on purchase of subsidiaries	22,713			3,282		366,519			3,282
Assumed business	103,615			—		1,631,166			1,432,412
Net balance as at September 30	6,602,527			5,532,552		6,602,527			5,532,552
Plus: reinsurance reserves recoverable	1,846,187			1,998,001		1,846,187			1,998,001
Plus: deferred charges on retroactive reinsurance	87,019			85,164		87,019			85,164
Balance as at September 30	$	8,535,733		$	7,615,717	$	8,535,733		$	7,615,717

The tables below provide the net incurred losses and LAE by segment for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended												Three Months Ended
	September 30, 2018												September 30, 2017
	Non-life Run-off			Atrium			StarStone			Total			Non-life Run-off			Atrium			StarStone			Total
Net losses paid	$	195,770		$	16,310		$	108,895		$	320,975		$	136,014		$	14,131		$	80,956		$	231,101
Net change in case and LAE reserves	(128,662		)	(546		)	17,549			(111,659		)	(66,392		)	239			(934		)	(67,087		)
Net change in IBNR reserves	(102,148		)	2,818			71,160			(28,170		)	(120,766		)	22,525			30,173			(68,068		)
Increase (reduction) in estimates of net ultimate losses	(35,040		)	18,582			197,604			181,146			(51,144		)	36,895			110,195			95,946
Increase in provisions for bad debt	—			—			—			—			—			242			—			242
Increase (reduction) in provisions for unallocated LAE	(24,460		)	(2		)	1,582			(22,880		)	(16,038		)	64			1,247			(14,727		)
Amortization of deferred charges	1,582			—			—			1,582			3,311			—			—			3,311
Amortization of fair value adjustments	4,247			(727		)	(287		)	3,233			3,493			(1,928		)	(121		)	1,444
Changes in fair value - fair value option	(9,107		)	—			—			(9,107		)	(10,504		)	—			—			(10,504		)
Net incurred losses and LAE	$	(62,778	)	$	17,853		$	198,899		$	153,974		$	(70,882	)	$	35,273		$	111,321		$	75,712



	Nine Months Ended												Nine Months Ended
	September 30, 2018												September 30, 2017
	Non-life Run-off			Atrium			StarStone			Total			Non-life Run-off			Atrium			StarStone			Total
Net losses paid	$	644,665		$	53,187		$	302,837		$	1,000,689		$	436,998		$	40,625		$	233,314		$	710,937
Net change in case and LAE reserves	(376,512		)	(98		)	38,915			(337,695		)	(276,935		)	(288		)	(2,148		)	(279,371		)
Net change in IBNR reserves	(413,898		)	2,964			75,031			(335,903		)	(261,724		)	17,179			13,371			(231,174		)
Increase (reduction) in estimates of net ultimate losses	(145,745		)	56,053			416,783			327,091			(101,661		)	57,516			244,537			200,392
Increase (reduction) in provisions for bad debt	—			—			—			—			(735		)	242			—			(493		)
Increase (reduction) in provisions for unallocated LAE	(48,723		)	—			4,012			(44,711		)	(41,296		)	—			1,533			(39,763		)
Amortization of deferred charges	10,381			—			—			10,381			9,387			—			—			9,387
Amortization of fair value adjustments	10,312			(4,102		)	(529		)	5,681			5,518			(1,808		)	(755		)	2,955
Changes in fair value - fair value option	(32,115		)	—			—			(32,115		)	(9,254		)	—			—			(9,254		)
Net incurred losses and LAE	$	(205,890	)	$	51,951		$	420,266		$	266,327		$	(138,041	)	$	55,950		$	245,315		$	163,224

Non-Life Run-off Segment

The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the three and nine months ended September 30, 2018 and 2017 for the Non-life Run-off segment:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Balance as at beginning of period	$	7,025,750		$	6,317,279		$	5,949,472		$	4,716,363
Less: reinsurance reserves recoverable	1,462,139			1,500,557			1,377,485			1,000,953
Less: deferred charges on retroactive insurance	71,393			88,475			80,192			94,551
Net balance as at beginning of period	5,492,218			4,728,247			4,491,795			3,620,859
Net incurred losses and LAE:
Current period	10,017			30			15,476			1,205
Prior periods	(72,795)			(70,912		)	(221,366		)	(139,246		)
Total net incurred losses and LAE	(62,778)			(70,882		)	(205,890		)	(138,041		)
Net paid losses:
Current period	(2,713)			(33		)	(3,304		)	(404		)
Prior periods	(193,057)			(135,981		)	(641,361		)	(436,594		)
Total net paid losses	(195,770)			(136,014		)	(644,665		)	(436,998		)
Effect of exchange rate movement	(26,352		)	46,080			(102,030)			120,592
Acquired on purchase of subsidiaries	22,713			3,282			173,538			3,282
Assumed business	103,615			—			1,620,898			1,401,019
Net balance as at September 30	5,333,646			4,570,713			5,333,646			4,570,713
Plus: reinsurance reserves recoverable	1,412,090			1,475,855			1,412,090			1,475,855
Plus: deferred charges on retroactive reinsurance	87,019			85,164			87,019			85,164
Balance as at September 30	$	6,832,755		$	6,131,732		$	6,832,755		$	6,131,732

Net incurred losses and LAE in the Non-life Run-off segment for the three months ended September 30, 2018 and 2017 were as follows:



	Three Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period			Total
Net losses paid	$	193,057		$	2,713	$	195,770		$	135,981		$	33		$	136,014
Net change in case and LAE reserves	(128,827		)	165		(128,662		)	(66,376		)	(16		)	(66,392		)
Net change in IBNR reserves	(109,287		)	7,139		(102,148		)	(120,614		)	(152		)	(120,766		)
Increase (reduction) in estimates of net ultimate losses	(45,057		)	10,017		(35,040		)	(51,009		)	(135		)	(51,144		)
Increase (reduction) in provisions for unallocated LAE	(24,460		)	—		(24,460		)	(16,203		)	165			(16,038		)
Amortization of deferred charges	1,582			—		1,582			3,311			—			3,311
Amortization of fair value adjustments	4,247			—		4,247			3,493			—			3,493
Changes in fair value - fair value option	(9,107		)	—		(9,107		)	(10,504		)	—			(10,504		)
Net incurred losses and LAE	$	(72,795	)	$	10,017	$	(62,778	)	$	(70,912	)	$	30		$	(70,882	)

Net change in case and LAE reserves comprises the movement during the period in specific case reserve liabilities as a result of claims settlements or changes advised to us by our policyholders and attorneys, less changes in case reserves recoverable advised by us to our reinsurers as a result of the settlement or movement of assumed claims. Net change in IBNR represents the gross change in our actuarial estimates of IBNR, less amounts recoverable.

Three Months Ended September 30, 2018

The reduction in net incurred losses and LAE for the three months ended September 30, 2018 of $62.8 million included net incurred losses and LAE of $10.0 million related to current period net earned premium. Excluding current period net incurred losses and LAE of $10.0 million, the reduction in net incurred losses and LAE liabilities relating to prior periods was $72.8 million, which was attributable to a reduction in estimates of net ultimate losses of $45.1 million, a reduction in provisions for unallocated LAE of $24.5 million relating to 2018 run-off activity and a reduction in the fair value of liabilities of $9.1 million related to our assumed retroactive reinsurance agreements for which we have elected the fair value option, partially offset by amortization of fair value adjustments over the estimated payout period relating to companies acquired of $4.2 million and the amortization of the deferred charges of $1.6 million. The reduction in estimates of net ultimate losses of $45.1 million for the three months ended September 30, 2018 included a net reduction in case and IBNR reserves of $238.1 million, partially offset by net losses paid of $193.1 million.

Three Months Ended September 30, 2017

The reduction in net incurred losses and LAE for the three months ended September 30, 2017 of $70.9 million included net incurred losses and LAE of $30 thousand related to current period net earned premium, primarily for the run-off business acquired with Sussex. Excluding current period net incurred losses and LAE of $30 thousand, the reduction in net incurred losses and LAE liabilities relating to prior periods was $70.9 million, which was attributable to a reduction in estimates of net ultimate losses of $51.0 million, and a reduction in provisions for unallocated LAE of $16.2 million, relating to 2017 run-off activity and a reduction in the fair value of liabilities of $10.5 million related to our assumed retroactive reinsurance agreements for which we have elected the fair value option, partially offset by the amortization of fair value adjustments over the estimated payout period relating to companies acquired amounting to $3.5 million and the amortization of the deferred charges of $3.3 million. The reduction in estimates of net ultimate losses of $51.0 million for the three months ended September 30, 2017 included a net change in case and IBNR reserves of $187.0 million, partially offset by net losses paid of $136.0 million.

Net incurred losses and LAE in the Non-life Run-off segment for the nine months ended September 30, 2018 and 2017 were as follows:



	Nine Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period			Total
Net losses paid	$	641,361		$	3,304	$	644,665		$	436,594		$	404		$	436,998
Net change in case and LAE reserves	(377,735		)	1,223		(376,512		)	(276,903		)	(32		)	(276,935		)
Net change in IBNR reserves	(424,847		)	10,949		(413,898		)	(262,296		)	572			(261,724		)
Increase (reduction) in estimates of net ultimate losses	(161,221		)	15,476		(145,745		)	(102,605		)	944			(101,661		)
Reduction in provisions for bad debt	—			—		—			(735		)	—			(735		)
Increase (reduction) in provisions for unallocated LAE	(48,723		)	—		(48,723		)	(41,557		)	261			(41,296		)
Amortization of deferred charges	10,381			—		10,381			9,387			—			9,387
Amortization of fair value adjustments	10,312			—		10,312			5,518			—			5,518
Changes in fair value - fair value option	(32,115		)	—		(32,115		)	(9,254		)	—			(9,254		)
Net incurred losses and LAE	$	(221,366	)	$	15,476	$	(205,890	)	$	(139,246	)	$	1,205		$	(138,041	)

Nine Months Ended September 30, 2018

The reduction in net incurred losses and LAE for the nine months ended September 30, 2018 of $205.9 million included net incurred losses and LAE of $15.5 million related to current period net earned premium. Excluding current period net incurred losses and LAE of $15.5 million, net incurred losses and LAE liabilities relating to prior periods were reduced by $221.4 million, which was attributable to a reduction in estimates of net ultimate losses of $161.2 million, a reduction in provisions for unallocated LAE of $48.7 million and a reduction in the fair value of liabilities of $32.1 million related to our assumed retroactive reinsurance agreements for which we have elected the fair value option, partially offset by amortization of the deferred charges of $10.4 million and amortization of fair value adjustments over the estimated payout period relating to companies acquired of $10.3 million. The reduction in estimates of net ultimate losses of $161.2 million for the nine months ended September 30, 2018 included a net change in case and IBNR reserves of $802.6 million, partially offset by net losses paid of $641.4 million.

Nine Months Ended September 30, 2017

The reduction in net incurred losses and LAE for the nine months ended September 30, 2017 of $138.0 million included net incurred losses and LAE of $1.2 million related to current period net earned premium, related to the run-off business acquired with Sussex. Excluding current period net incurred losses and LAE of $1.2 million, net incurred losses and LAE liabilities relating to prior periods were reduced by $139.2 million, which was attributable to a reduction in estimates of net ultimate losses of $102.6 million, a reduction in provisions for unallocated LAE of $41.6 million, a reduction in the fair value of liabilities of $9.3 million related to our assumed retroactive reinsurance agreements for which we have elected the fair value option and a reduction in provisions for bad debt of $0.7 million, partially offset by amortization of the deferred charges of $9.4 million and amortization of fair value adjustments over the estimated payout period relating to companies acquired amounting to $5.5 million. The reduction in estimates of net ultimate losses of $102.6 million for the nine months ended September 30, 2017 included a net change in case and IBNR reserves of $539.2 million, partially offset by net losses paid of $436.6 million.

Atrium

The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the three and nine months ended September 30, 2018 and 2017 for the Atrium segment:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Balance as at beginning of period	$	234,232		$	208,646		$	240,873		$	212,122
Less: reinsurance reserves recoverable	38,253			29,749			40,531			30,009
Net balance as at beginning of period	195,979			178,897			200,342			182,113
Net incurred losses and LAE:
Current period	20,033			37,284			56,514			66,563
Prior periods	(2,180		)	(2,011		)	(4,563		)	(10,613		)
Total net incurred losses and LAE	17,853			35,273			51,951			55,950
Net paid losses:
Current period	(8,080		)	(5,139		)	(25,699		)	(14,799		)
Prior periods	(8,230		)	(8,992		)	(27,488		)	(25,826		)
Total net paid losses	(16,310		)	(14,131		)	(53,187		)	(40,625		)
Effect of exchange rate movement	(137		)	1,474			(1,721		)	4,075
Net balance as at September 30	197,385			201,513			197,385			201,513
Plus: reinsurance reserves recoverable	45,382			44,207			45,382			44,207
Balance as at September 30	$	242,767		$	245,720		$	242,767		$	245,720

Net incurred losses and LAE in the Atrium segment for the three and nine months ended September 30, 2018 and 2017 were as follows:



	Three Months Ended September 30,
	2018					2017
	Prior Period		Current Period	Total		Prior Period		Current Period		Total
Net losses paid	8,230		8,080	16,310		8,992		5,139		14,131
Net change in case and LAE reserves	(4,142	)	3,596	(546	)	(2,781	)	3,020		239
Net change in IBNR reserves	(5,539	)	8,357	2,818		(6,273	)	28,798		22,525
Increase (reduction) in estimates of net ultimate losses	(1,451	)	20,033	18,582		(62	)	36,957		36,895
Increase (reduction) in provisions for bad debt	—		—	—		(96	)	338		242
Increase (reduction) in provisions for unallocated LAE	(2	)	—	(2	)	75		(11	)	64
Amortization of fair value adjustments	(727	)	—	(727	)	(1,928	)	—		(1,928	)
Net incurred losses and LAE	(2,180	)	20,033	17,853		(2,011	)	37,284		35,273



	Nine Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period		Total
Net losses paid	$	27,488		$	25,699	$	53,187		$	25,826		$	14,799	$	40,625
Net change in case and LAE reserves	(9,695		)	9,597		(98		)	(7,904		)	7,616		(288		)
Net change in IBNR reserves	(18,254		)	21,218		2,964			(26,631		)	43,810		17,179
Increase (reduction) in estimates of net ultimate losses	(461		)	56,514		56,053			(8,709		)	66,225		57,516
Increase (reduction) in provisions for bad debt	—			—		—			(96		)	338		242
Amortization of fair value adjustments	(4,102		)	—		(4,102		)	(1,808		)	—		(1,808		)
Net incurred losses and LAE	$	(4,563	)	$	56,514	$	51,951		$	(10,613	)	$	66,563	$	55,950

StarStone

The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the three and nine months ended September 30, 2018 and 2017 for our StarStone segment:



	Three Months Ended					Nine Months Ended
	September 30,					September 30,
	2018		2017			2018			2017
Balance as at beginning of period	$	1,348,405	$	1,115,459		$	1,207,743		$	1,059,382
Less: reinsurance reserves recoverable	366,577		393,656			452,017			357,231
Net balance as at beginning of period	981,828		721,803			755,726			702,151
Net incurred losses and LAE:
Current period	189,000		110,532			396,074			247,023
Prior periods	9,899		789			24,192			(1,708		)
Total net incurred losses and LAE	198,899		111,321			420,266			245,315
Net paid losses:
Current period	(13,473)		(10,756		)	(33,840		)	(25,617		)
Prior periods	(95,422)		(70,200		)	(268,997		)	(207,697		)
Total net paid losses	(108,895)		(80,956		)	(302,837		)	(233,314		)
Effect of exchange rate movement	(336)		8,158			(4,908		)	14,781
Acquired on purchase of subsidiaries	—		—			192,981			—
Assumed business	—		—			10,268			31,393
Net balance as at September 30	1,071,496		760,326			1,071,496			760,326
Plus: reinsurance reserves recoverable	388,715		477,939			388,715			477,939
Balance as at September 30	$	1,460,211	$	1,238,265		$	1,460,211		$	1,238,265

Net incurred losses and LAE in the StarStone segment for the three and nine months ended September 30, 2018 and 2017 were as follows:



	Three Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period		Total
Net losses paid	$	95,422		$	13,473	$	108,895		$	70,200		$	10,756	$	80,956
Net change in case and LAE reserves	(19,919		)	37,468		17,549			(14,037		)	13,103		(934		)
Net change in IBNR reserves	(63,294		)	134,454		71,160			(54,400		)	84,573		30,173
Increase in estimates of net ultimate losses	12,209			185,395		197,604			1,763			108,432		110,195
Increase (reduction) in provisions for unallocated LAE	(2,023		)	3,605		1,582			(853		)	2,100		1,247
Amortization of fair value adjustments	(287		)	—		(287		)	(121		)	—		(121		)
Net incurred losses and LAE	$	9,899		$	189,000	$	198,899		$	789		$	110,532	$	111,321



	Nine Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period		Total
Net losses paid	$	268,997		$	33,840	$	302,837		$	207,697		$	25,617	$	233,314
Net change in case and LAE reserves	(55,541		)	94,456		38,915			(55,501		)	53,353		(2,148		)
Net change in IBNR reserves	(183,422		)	258,453		75,031			(149,165		)	162,536		13,371
Increase in estimates of net ultimate losses	30,034			386,749		416,783			3,031			241,506		244,537
Increase (reduction) in provisions for unallocated LAE	(5,313		)	9,325		4,012			(3,984		)	5,517		1,533
Amortization of fair value adjustments	(529		)	—		(529		)	(755		)	—		(755		)
Net incurred losses and LAE	$	24,192		$	396,074	$	420,266		$	(1,708	)	$	247,023	$	245,315

11. POLICY BENEFITS FOR LIFE CONTRACTS

We have acquired long duration contracts that subject us to mortality, longevity and morbidity risks and which are accounted for as life and annuity premiums earned. Life benefit reserves are established using assumptions for investment yields, mortality, morbidity, lapse and expenses, including a provision for adverse deviation. We establish and review our life reserves regularly based upon cash flow projections. We establish and maintain our life reinsurance reserves at a level that we estimate will, when taken together with future premium payments and investment income expected to be earned on associated premiums, be sufficient to support all future cash flow benefit obligations and third-party servicing obligations as they become payable. Policy benefits for life contracts as at September 30, 2018 and December 31, 2017 were $107.5 million and $117.2 million, respectively. Refer to Note 2 - "Significant Accounting Policies" - (d) Policy Benefits for Life and Annuity Contracts" of the consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2017 for a description of the assumptions used and the process for establishing our assumptions and estimates.

On October 10, 2018, we entered into a Business Transfer Agreement between our wholly-owned subsidiary Alpha Insurance SA and a subsidiary of Monument Insurance Group Limited ("Monument"). This agreement will transfer our remaining life assurance policies to Monument, via a Portfolio Transfer, subject to regulatory approval. The transaction is expected to close in the first half of 2019. Our policy benefits operations do not qualify for inclusion in our reportable segments and are therefore included within other activities. The related assets, as well as the results from these operations, were not significant to our consolidated operations and therefore they have not been classified as a discontinued operation. In addition, our proposed transfer of these life assurance polices to Monument was not classified as a held-for-sale business transaction since the underlying contracts do not meet the definition of a business.

Policy Benefits for Life Contracts

9 Months Ended

Sep. 30, 2018

Insurance [Abstract]

POLICY BENEFITS FOR LIFE CONTRACTS

10. LOSSES AND LOSS ADJUSTMENT EXPENSES

The following table summarizes the liability for losses and LAE by segment as at September 30, 2018 and December 31, 2017:



	September 30, 2018
	Non-life Run-off			Atrium		StarStone			Total
Outstanding losses	$	3,998,430		$	83,138	$	714,231		$	4,795,799
IBNR	3,072,291			152,462		723,987			3,948,740
Fair value adjustments	(120,916		)	4,749		(381		)	(116,548		)
Fair value adjustments - fair value option	(457,215		)	—		—			(457,215		)
ULAE	340,165			2,418		22,374			364,957
Total	$	6,832,755		$	242,767	$	1,460,211		$	8,535,733

Reconciliation to Consolidated Balance Sheet:
Loss and loss adjustment expenses	$	3,813,034		$	242,767	$	1,460,211		$	5,516,012
Loss and loss adjustment expenses, at fair value	3,019,721			—		—			3,019,721
Total	$	6,832,755		$	242,767	$	1,460,211		$	8,535,733



	December 31, 2017
	Non-life Run-off			Atrium		StarStone			Total
Outstanding losses	$	3,185,703		$	78,363	$	590,977		$	3,855,043
IBNR	2,903,927			150,508		599,221			3,653,656
Fair value adjustments	(125,998		)	9,547		(555		)	(117,006		)
Fair value adjustments - fair value option	(314,748		)	—		—			(314,748		)
ULAE	300,588			2,455		18,100			321,143
Total	$	5,949,472		$	240,873	$	1,207,743		$	7,398,088

Reconciliation to Consolidated Balance Sheet:
Loss and loss adjustment expenses	$	4,154,803		$	240,873	$	1,207,743		$	5,603,419
Loss and loss adjustment expenses, at fair value	$	1,794,669		$	—	$	—		$	1,794,669
Total	$	5,949,472		$	240,873	$	1,207,743		$	7,398,088

The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended					Nine Months Ended
	September 30,					September 30,
	2018			2017		2018			2017
Balance as at beginning of period	$	8,608,387		$	7,641,384	$	7,398,088		$	5,987,867
Less: reinsurance reserves recoverable	1,866,969			1,923,962		1,870,033			1,388,193
Less: deferred charges on retroactive reinsurance	71,393			88,475		80,192			94,551
Net balance as at beginning of period	6,670,025			5,628,947		5,447,863			4,505,123
Net incurred losses and LAE:
Current period	219,050			147,846		468,064			314,791
Prior periods	(65,076		)	(72,134)		(201,737		)	(151,567		)
Total net incurred losses and LAE	153,974			75,712		266,327			163,224
Net paid losses:
Current period	(24,266		)	(15,928)		(62,843		)	(40,820		)
Prior periods	(296,709		)	(215,173)		(937,846		)	(670,117		)
Total net paid losses	(320,975		)	(231,101)		(1,000,689		)	(710,937		)
Effect of exchange rate movement	(26,825		)	55,712		(108,659		)	139,448
Acquired on purchase of subsidiaries	22,713			3,282		366,519			3,282
Assumed business	103,615			—		1,631,166			1,432,412
Net balance as at September 30	6,602,527			5,532,552		6,602,527			5,532,552
Plus: reinsurance reserves recoverable	1,846,187			1,998,001		1,846,187			1,998,001
Plus: deferred charges on retroactive reinsurance	87,019			85,164		87,019			85,164
Balance as at September 30	$	8,535,733		$	7,615,717	$	8,535,733		$	7,615,717

The tables below provide the net incurred losses and LAE by segment for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended												Three Months Ended
	September 30, 2018												September 30, 2017
	Non-life Run-off			Atrium			StarStone			Total			Non-life Run-off			Atrium			StarStone			Total
Net losses paid	$	195,770		$	16,310		$	108,895		$	320,975		$	136,014		$	14,131		$	80,956		$	231,101
Net change in case and LAE reserves	(128,662		)	(546		)	17,549			(111,659		)	(66,392		)	239			(934		)	(67,087		)
Net change in IBNR reserves	(102,148		)	2,818			71,160			(28,170		)	(120,766		)	22,525			30,173			(68,068		)
Increase (reduction) in estimates of net ultimate losses	(35,040		)	18,582			197,604			181,146			(51,144		)	36,895			110,195			95,946
Increase in provisions for bad debt	—			—			—			—			—			242			—			242
Increase (reduction) in provisions for unallocated LAE	(24,460		)	(2		)	1,582			(22,880		)	(16,038		)	64			1,247			(14,727		)
Amortization of deferred charges	1,582			—			—			1,582			3,311			—			—			3,311
Amortization of fair value adjustments	4,247			(727		)	(287		)	3,233			3,493			(1,928		)	(121		)	1,444
Changes in fair value - fair value option	(9,107		)	—			—			(9,107		)	(10,504		)	—			—			(10,504		)
Net incurred losses and LAE	$	(62,778	)	$	17,853		$	198,899		$	153,974		$	(70,882	)	$	35,273		$	111,321		$	75,712



	Nine Months Ended												Nine Months Ended
	September 30, 2018												September 30, 2017
	Non-life Run-off			Atrium			StarStone			Total			Non-life Run-off			Atrium			StarStone			Total
Net losses paid	$	644,665		$	53,187		$	302,837		$	1,000,689		$	436,998		$	40,625		$	233,314		$	710,937
Net change in case and LAE reserves	(376,512		)	(98		)	38,915			(337,695		)	(276,935		)	(288		)	(2,148		)	(279,371		)
Net change in IBNR reserves	(413,898		)	2,964			75,031			(335,903		)	(261,724		)	17,179			13,371			(231,174		)
Increase (reduction) in estimates of net ultimate losses	(145,745		)	56,053			416,783			327,091			(101,661		)	57,516			244,537			200,392
Increase (reduction) in provisions for bad debt	—			—			—			—			(735		)	242			—			(493		)
Increase (reduction) in provisions for unallocated LAE	(48,723		)	—			4,012			(44,711		)	(41,296		)	—			1,533			(39,763		)
Amortization of deferred charges	10,381			—			—			10,381			9,387			—			—			9,387
Amortization of fair value adjustments	10,312			(4,102		)	(529		)	5,681			5,518			(1,808		)	(755		)	2,955
Changes in fair value - fair value option	(32,115		)	—			—			(32,115		)	(9,254		)	—			—			(9,254		)
Net incurred losses and LAE	$	(205,890	)	$	51,951		$	420,266		$	266,327		$	(138,041	)	$	55,950		$	245,315		$	163,224

Non-Life Run-off Segment

The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the three and nine months ended September 30, 2018 and 2017 for the Non-life Run-off segment:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Balance as at beginning of period	$	7,025,750		$	6,317,279		$	5,949,472		$	4,716,363
Less: reinsurance reserves recoverable	1,462,139			1,500,557			1,377,485			1,000,953
Less: deferred charges on retroactive insurance	71,393			88,475			80,192			94,551
Net balance as at beginning of period	5,492,218			4,728,247			4,491,795			3,620,859
Net incurred losses and LAE:
Current period	10,017			30			15,476			1,205
Prior periods	(72,795)			(70,912		)	(221,366		)	(139,246		)
Total net incurred losses and LAE	(62,778)			(70,882		)	(205,890		)	(138,041		)
Net paid losses:
Current period	(2,713)			(33		)	(3,304		)	(404		)
Prior periods	(193,057)			(135,981		)	(641,361		)	(436,594		)
Total net paid losses	(195,770)			(136,014		)	(644,665		)	(436,998		)
Effect of exchange rate movement	(26,352		)	46,080			(102,030)			120,592
Acquired on purchase of subsidiaries	22,713			3,282			173,538			3,282
Assumed business	103,615			—			1,620,898			1,401,019
Net balance as at September 30	5,333,646			4,570,713			5,333,646			4,570,713
Plus: reinsurance reserves recoverable	1,412,090			1,475,855			1,412,090			1,475,855
Plus: deferred charges on retroactive reinsurance	87,019			85,164			87,019			85,164
Balance as at September 30	$	6,832,755		$	6,131,732		$	6,832,755		$	6,131,732

Net incurred losses and LAE in the Non-life Run-off segment for the three months ended September 30, 2018 and 2017 were as follows:



	Three Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period			Total
Net losses paid	$	193,057		$	2,713	$	195,770		$	135,981		$	33		$	136,014
Net change in case and LAE reserves	(128,827		)	165		(128,662		)	(66,376		)	(16		)	(66,392		)
Net change in IBNR reserves	(109,287		)	7,139		(102,148		)	(120,614		)	(152		)	(120,766		)
Increase (reduction) in estimates of net ultimate losses	(45,057		)	10,017		(35,040		)	(51,009		)	(135		)	(51,144		)
Increase (reduction) in provisions for unallocated LAE	(24,460		)	—		(24,460		)	(16,203		)	165			(16,038		)
Amortization of deferred charges	1,582			—		1,582			3,311			—			3,311
Amortization of fair value adjustments	4,247			—		4,247			3,493			—			3,493
Changes in fair value - fair value option	(9,107		)	—		(9,107		)	(10,504		)	—			(10,504		)
Net incurred losses and LAE	$	(72,795	)	$	10,017	$	(62,778	)	$	(70,912	)	$	30		$	(70,882	)

Three Months Ended September 30, 2018

Three Months Ended September 30, 2017

Net incurred losses and LAE in the Non-life Run-off segment for the nine months ended September 30, 2018 and 2017 were as follows:



	Nine Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period			Total
Net losses paid	$	641,361		$	3,304	$	644,665		$	436,594		$	404		$	436,998
Net change in case and LAE reserves	(377,735		)	1,223		(376,512		)	(276,903		)	(32		)	(276,935		)
Net change in IBNR reserves	(424,847		)	10,949		(413,898		)	(262,296		)	572			(261,724		)
Increase (reduction) in estimates of net ultimate losses	(161,221		)	15,476		(145,745		)	(102,605		)	944			(101,661		)
Reduction in provisions for bad debt	—			—		—			(735		)	—			(735		)
Increase (reduction) in provisions for unallocated LAE	(48,723		)	—		(48,723		)	(41,557		)	261			(41,296		)
Amortization of deferred charges	10,381			—		10,381			9,387			—			9,387
Amortization of fair value adjustments	10,312			—		10,312			5,518			—			5,518
Changes in fair value - fair value option	(32,115		)	—		(32,115		)	(9,254		)	—			(9,254		)
Net incurred losses and LAE	$	(221,366	)	$	15,476	$	(205,890	)	$	(139,246	)	$	1,205		$	(138,041	)

Nine Months Ended September 30, 2018

Nine Months Ended September 30, 2017

Atrium

The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the three and nine months ended September 30, 2018 and 2017 for the Atrium segment:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Balance as at beginning of period	$	234,232		$	208,646		$	240,873		$	212,122
Less: reinsurance reserves recoverable	38,253			29,749			40,531			30,009
Net balance as at beginning of period	195,979			178,897			200,342			182,113
Net incurred losses and LAE:
Current period	20,033			37,284			56,514			66,563
Prior periods	(2,180		)	(2,011		)	(4,563		)	(10,613		)
Total net incurred losses and LAE	17,853			35,273			51,951			55,950
Net paid losses:
Current period	(8,080		)	(5,139		)	(25,699		)	(14,799		)
Prior periods	(8,230		)	(8,992		)	(27,488		)	(25,826		)
Total net paid losses	(16,310		)	(14,131		)	(53,187		)	(40,625		)
Effect of exchange rate movement	(137		)	1,474			(1,721		)	4,075
Net balance as at September 30	197,385			201,513			197,385			201,513
Plus: reinsurance reserves recoverable	45,382			44,207			45,382			44,207
Balance as at September 30	$	242,767		$	245,720		$	242,767		$	245,720

Net incurred losses and LAE in the Atrium segment for the three and nine months ended September 30, 2018 and 2017 were as follows:



	Three Months Ended September 30,
	2018					2017
	Prior Period		Current Period	Total		Prior Period		Current Period		Total
Net losses paid	8,230		8,080	16,310		8,992		5,139		14,131
Net change in case and LAE reserves	(4,142	)	3,596	(546	)	(2,781	)	3,020		239
Net change in IBNR reserves	(5,539	)	8,357	2,818		(6,273	)	28,798		22,525
Increase (reduction) in estimates of net ultimate losses	(1,451	)	20,033	18,582		(62	)	36,957		36,895
Increase (reduction) in provisions for bad debt	—		—	—		(96	)	338		242
Increase (reduction) in provisions for unallocated LAE	(2	)	—	(2	)	75		(11	)	64
Amortization of fair value adjustments	(727	)	—	(727	)	(1,928	)	—		(1,928	)
Net incurred losses and LAE	(2,180	)	20,033	17,853		(2,011	)	37,284		35,273



	Nine Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period		Total
Net losses paid	$	27,488		$	25,699	$	53,187		$	25,826		$	14,799	$	40,625
Net change in case and LAE reserves	(9,695		)	9,597		(98		)	(7,904		)	7,616		(288		)
Net change in IBNR reserves	(18,254		)	21,218		2,964			(26,631		)	43,810		17,179
Increase (reduction) in estimates of net ultimate losses	(461		)	56,514		56,053			(8,709		)	66,225		57,516
Increase (reduction) in provisions for bad debt	—			—		—			(96		)	338		242
Amortization of fair value adjustments	(4,102		)	—		(4,102		)	(1,808		)	—		(1,808		)
Net incurred losses and LAE	$	(4,563	)	$	56,514	$	51,951		$	(10,613	)	$	66,563	$	55,950

StarStone

The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the three and nine months ended September 30, 2018 and 2017 for our StarStone segment:



	Three Months Ended					Nine Months Ended
	September 30,					September 30,
	2018		2017			2018			2017
Balance as at beginning of period	$	1,348,405	$	1,115,459		$	1,207,743		$	1,059,382
Less: reinsurance reserves recoverable	366,577		393,656			452,017			357,231
Net balance as at beginning of period	981,828		721,803			755,726			702,151
Net incurred losses and LAE:
Current period	189,000		110,532			396,074			247,023
Prior periods	9,899		789			24,192			(1,708		)
Total net incurred losses and LAE	198,899		111,321			420,266			245,315
Net paid losses:
Current period	(13,473)		(10,756		)	(33,840		)	(25,617		)
Prior periods	(95,422)		(70,200		)	(268,997		)	(207,697		)
Total net paid losses	(108,895)		(80,956		)	(302,837		)	(233,314		)
Effect of exchange rate movement	(336)		8,158			(4,908		)	14,781
Acquired on purchase of subsidiaries	—		—			192,981			—
Assumed business	—		—			10,268			31,393
Net balance as at September 30	1,071,496		760,326			1,071,496			760,326
Plus: reinsurance reserves recoverable	388,715		477,939			388,715			477,939
Balance as at September 30	$	1,460,211	$	1,238,265		$	1,460,211		$	1,238,265

Net incurred losses and LAE in the StarStone segment for the three and nine months ended September 30, 2018 and 2017 were as follows:



	Three Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period		Total
Net losses paid	$	95,422		$	13,473	$	108,895		$	70,200		$	10,756	$	80,956
Net change in case and LAE reserves	(19,919		)	37,468		17,549			(14,037		)	13,103		(934		)
Net change in IBNR reserves	(63,294		)	134,454		71,160			(54,400		)	84,573		30,173
Increase in estimates of net ultimate losses	12,209			185,395		197,604			1,763			108,432		110,195
Increase (reduction) in provisions for unallocated LAE	(2,023		)	3,605		1,582			(853		)	2,100		1,247
Amortization of fair value adjustments	(287		)	—		(287		)	(121		)	—		(121		)
Net incurred losses and LAE	$	9,899		$	189,000	$	198,899		$	789		$	110,532	$	111,321



	Nine Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period		Total
Net losses paid	$	268,997		$	33,840	$	302,837		$	207,697		$	25,617	$	233,314
Net change in case and LAE reserves	(55,541		)	94,456		38,915			(55,501		)	53,353		(2,148		)
Net change in IBNR reserves	(183,422		)	258,453		75,031			(149,165		)	162,536		13,371
Increase in estimates of net ultimate losses	30,034			386,749		416,783			3,031			241,506		244,537
Increase (reduction) in provisions for unallocated LAE	(5,313		)	9,325		4,012			(3,984		)	5,517		1,533
Amortization of fair value adjustments	(529		)	—		(529		)	(755		)	—		(755		)
Net incurred losses and LAE	$	24,192		$	396,074	$	420,266		$	(1,708	)	$	247,023	$	245,315

11. POLICY BENEFITS FOR LIFE CONTRACTS

Premiums Written and Earned

9 Months Ended

Sep. 30, 2018

Insurance [Abstract]

PREMIUMS WRITTEN AND EARNED

9. REINSURANCE BALANCES RECOVERABLE

The following tables provide the total reinsurance balances recoverable as at September 30, 2018 and December 31, 2017:



	September 30, 2018
	Non-life Run-off			Atrium			StarStone			Total
Recoverable from reinsurers on unpaid:
Outstanding losses	$	932,142		$	13,051		$	214,963		$	1,160,156
IBNR	664,873			31,445			175,302			871,620
Fair value adjustments	(14,489		)	886			(1,550		)	(15,153		)
Fair value adjustments - fair value option	(170,436		)	—			—			(170,436		)
Total reinsurance reserves recoverable	1,412,090			45,382			388,715			1,846,187
Paid losses recoverable	108,218			(1,808		)	22,959			129,369
	$	1,520,308		$	43,574		$	411,674		$	1,975,556
Reconciliation to Consolidated Balance Sheet:
Reinsurance balances recoverable	$	727,755		$	43,574		$	411,674		$	1,183,003
Reinsurance balances recoverable - fair value option	792,553			—			—			792,553
Total	$	1,520,308		$	43,574		$	411,674		$	1,975,556



	December 31, 2017
	Non-life Run-off			Atrium			StarStone			Other		Total
Recoverable from reinsurers on unpaid:
Outstanding losses	$	932,284		$	7,472		$	211,650		$	16	$	1,151,422
IBNR	590,154			31,476			242,620			—		864,250
Fair value adjustments	(12,970		)	1,583			(2,253		)	—		(13,640		)
Fair value adjustments - fair value option	(131,983		)	—			—			—		(131,983		)
Total reinsurance reserves recoverable	1,377,485			40,531			452,017			16		1,870,049
Paid losses recoverable	128,253			(451		)	23,179			—		150,981
	$	1,505,738		$	40,080		$	475,196		$	16	$	2,021,030
Reconciliation to Consolidated Balance Sheet:
Reinsurance balances recoverable	$	963,514		$	40,080		$	475,196		$	16	$	1,478,806
Reinsurance balances recoverable - fair value option	542,224			—			—			—		542,224
Total	$	1,505,738		$	40,080		$	475,196		$	16	$	2,021,030

Top Ten Reinsurers



	September 30, 2018
	Non-life Run-off		Atrium		StarStone		Total		% of Total
Top ten reinsurers	$	1,167,500	$	28,669	$	239,686	$	1,435,855	72.7	%
Other reinsurers > $1 million	335,939		14,232		168,194		518,365		26.2	%
Other reinsurers < $1 million	16,869		673		3,794		21,336		1.1	%
Total	$	1,520,308	$	43,574	$	411,674	$	1,975,556	100.0	%



	December 31, 2017
	Non-life Run-off		Atrium		StarStone		Other		Total		% of Total
Top ten reinsurers	$	1,166,057	$	22,422	$	328,257	$	—	$	1,516,736	75.0	%
Other reinsurers > $1 million	322,722		16,631		144,336		—		483,689		24.0	%
Other reinsurers < $1 million	16,959		1,027		2,603		16		20,605		1.0	%
Total	$	1,505,738	$	40,080	$	475,196	$	16	$	2,021,030	100.0	%



	September 30, 2018		December 31, 2017
Information regarding top ten reinsurers:
Number of top 10 reinsurers rated A- or better	7		6
Number of top 10 non-rated reinsurers ⁽¹⁾	3		4

Top 10 rated A- or better reinsurers recoverables	$	1,116,423	$	829,164
Top 10 collaterized non-rated reinsurers recoverables ⁽¹⁾	$	319,432	$	687,572
	$	1,435,855	$	1,516,736

Single reinsurers that represent 10% or more of total reinsurance balance recoverables as at September 30, 2018:

Hannover Ruck SE ⁽²⁾	$	327,287	$	320,047
Lloyd's Syndicates ⁽³⁾	$	303,598	$	193,838

⁽²⁾ Hannover Ruck SE is rated AA- by Standard & Poor’s and A+ by A.M. Best.

⁽³⁾ Lloyd's Syndicates are rated A+ by Standard & Poor's and A by A.M. Best.

Provisions for Uncollectible Reinsurance Balances Recoverable

We evaluate and monitor concentration of credit risk among our reinsurers, and provisions are made for amounts considered potentially uncollectible.



	September 30, 2018								December 31, 2017
	Gross		Provisions for Bad Debt		Net		Provisions as a % of Gross		Gross		Provisions for Bad Debt		Net		Provisions as a % of Gross
Reinsurers rated A- or above	$	1,600,220	$	54,960	$	1,545,260	3.4	%	$	1,252,887	$	51,115	$	1,201,772	4.1	%
Reinsurers rated below A-, secured	397,775		—		397,775		—	%	771,097		—		771,097		—	%
Reinsurers rated below A-, unsecured	135,987		103,466		32,521		76.1	%	162,259		114,098		48,161		70.3	%
Total	$	2,133,982	$	158,426	$	1,975,556	7.4	%	$	2,186,243	$	165,213	$	2,021,030	7.6	%

12. PREMIUMS WRITTEN AND EARNED



	Three Months Ended September 30,												Nine Months Ended September 30,
	2018						2017						2018						2017
	Premiums Written			Premiums Earned			Premiums Written			Premiums Earned			Premiums Written			Premiums Earned			Premiums Written			Premiums Earned
Non-life Run-off
Gross	$	9,912		$	17,746		$	11,751		$	9,345		$	16,354		$	54,044		$	13,956		$	15,353
Ceded	(5,134		)	(7,304		)	(284		)	(2,930		)	(13,137		)	(26,815		)	(503		)	(5,497		)
Net	$	4,778		$	10,442		$	11,467		$	6,415		$	3,217		$	27,229		$	13,453		$	9,856
Atrium
Gross	$	39,995		$	42,505		$	36,377		$	39,591		$	130,997		$	121,974		$	117,355		$	111,633
Ceded	(2,854		)	(5,528		)	(10,388		)	(6,818		)	(17,779		)	(15,252		)	(18,120		)	(14,260		)
Net	$	37,141		$	36,977		$	25,989		$	32,773		$	113,218		$	106,722		$	99,235		$	97,373
StarStone
Gross	$	282,525		$	281,467		$	200,007		$	217,833		$	888,867		$	761,694		$	651,107		$	636,137
Ceded	(62,799		)	(65,112		)	(102,958		)	(110,183		)	(269,339		)	(234,892		)	(319,658		)	(294,528		)
Net	$	219,726		$	216,355		$	97,049		$	107,650		$	619,528		$	526,802		$	331,449		$	341,609
Other
Gross	$	846		$	848		$	2,424		$	1,444		$	2,858		$	2,878		$	4,506		$	4,658
Ceded	(24		)	(25		)	(753		)	(257		)	13			(3		)	(860		)	(1,002		)
Net	$	822		$	823		$	1,671		$	1,187		$	2,871		$	2,875		$	3,646		$	3,656
Total
Gross	$	333,278		$	342,566		$	250,559		$	268,213		$	1,039,076		$	940,590		$	786,924		$	767,781
Ceded	(70,811		)	(77,969		)	(114,383		)	(120,188		)	(300,242		)	(276,962		)	(339,141		)	(315,287		)
Total	$	262,467		$	264,597		$	136,176		$	148,025		$	738,834		$	663,628		$	447,783		$	452,494

Goodwill and Intangible Assets

9 Months Ended

Sep. 30, 2018

Goodwill, Intangible Assets, Intangible Assets Arising from Insurance Contracts Acquired in Business Combination, and Deferred Charges Disclosure [Abstract]

GOODWILL AND INTANGIBLE ASSETS

13. GOODWILL AND INTANGIBLE ASSETS

The following table presents a reconciliation of the beginning and ending goodwill, intangible assets and the deferred charges during the nine months ended September 30, 2018:



	Goodwill		Intangible assets with a definite life - Other			Intangible assets with an indefinite life		Total			Intangible assets with a definite life - FVA			Other assets - Deferred Charges
Balance as at January 1, 2018	$	73,071	$	20,487		$	87,031	$	180,589		$	140,393		$	80,192
Acquired during the period	41,736		—			—		41,736			3,976			17,208
Amortization	—		(3,030		)	—		(3,030		)	(6,138		)	(10,381		)
Balance as at September 30, 2018	$	114,807	$	17,457		$	87,031	$	219,295		$	138,231		$	87,019

Refer to Note 2 - "Acquisitions" for further details on the goodwill acquired during the period. Refer to Note 3 - "Significant New Business" for further details on the new deferred charges recorded during the period. Refer to Note 14 - "Goodwill, Intangible assets and Deferred Charges" to the consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2017 for more information on goodwill, intangible assets and the deferred charges.

The following table provides a summary of the amortization recorded on the intangible assets for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Intangible asset amortization	$	3,922	$	3,105	$	9,168	$	5,353

The gross carrying value, accumulated amortization and net carrying value of intangible assets by type and the deferred charges as at September 30, 2018 and December 31, 2017 were as follows:



	September 30, 2018									December 31, 2017
	Gross Carrying Value			Accumulated Amortization			Net Carrying Value			Gross Carrying Value			Accumulated Amortization			Net Carrying Value
Intangible assets with a definite life:
Fair value adjustments:
Losses and LAE liabilities	$	467,944		$	(351,396	)	$	116,548		$	462,455		$	(345,449	)	$	117,006
Reinsurance balances recoverable	(180,732		)	165,579			(15,153		)	(179,219		)	165,579			(13,640		)
Other Assets	(48,840		)	838			(48,002		)	(48,840		)	440			(48,400		)
Other Liabilities	85,845			(1,007		)	84,838			85,845			(418		)	85,427
Total	$	324,217		$	(185,986	)	$	138,231		$	320,241		$	(179,848	)	$	140,393
Other:
Distribution channel	$	20,000		$	(6,443	)	$	13,557		$	20,000		$	(5,444	)	$	14,556
Technology	15,000			(14,716		)	284			15,000			(13,210		)	1,790
Brand	7,000			(3,384		)	3,616			7,000			(2,859		)	4,141
Total	$	42,000		$	(24,543	)	$	17,457		$	42,000		$	(21,513	)	$	20,487
Intangible assets with an indefinite life:
Lloyd’s syndicate capacity	$	37,031		$	—		$	37,031		$	37,031		$	—		$	37,031
Licenses	19,900			—			19,900			19,900			—			19,900
Management contract	30,100			—			30,100			30,100			—			30,100
Total	$	87,031		$	—		$	87,031		$	87,031		$	—		$	87,031

Deferred charges on retroactive reinsurance	$	295,851		$	(208,832	)	$	87,019		$278,643			$	(198,451	)	$80,192

Debt Obligations

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

DEBT OBLIGATIONS

14. DEBT OBLIGATIONS

We utilize debt arrangements primarily for acquisitions and, from time to time, for general corporate purposes. Debt obligations as at September 30, 2018 and December 31, 2017 were as follows:



Facility	Origination Date	Term	September 30, 2018			December 31, 2017
Senior Notes	March 10, 2017	5 years	$	350,000		$	350,000
Less: Unamortized debt issuance costs			(2,030		)	(2,484		)
Total Senior Notes			347,970			347,516
EGL Revolving Credit Facility	August 16, 2018	5 years	46,500			—
Previous EGL Revolving Credit Facility	September 16, 2014	5 years	—			225,110
EGL Term Loan Facility	November 18, 2016	3 years	—			74,063
Total debt obligations			$	394,470		$	646,689

The table below provides a summary of the total interest expense for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Interest expense on debt obligations	$	4,552	$	6,219	$	20,822	$	18,576
Funds withheld balances and other	88		191		751		2,275
Total interest expense	$	4,640	$	6,410	$	21,573	$	20,851

Senior Notes

On March 10, 2017, we issued Senior Notes (the "Notes") for an aggregate principal amount of $350.0 million. The Notes pay 4.5% interest semi-annually and mature on March 10, 2022. The Notes are unsecured and unsubordinated obligations that rank equal to any of our other unsecured and unsubordinated obligations, senior to any future obligations that are expressly subordinated to the Notes, effectively subordinate to any of our secured indebtedness to the extent of the value of the assets securing such indebtedness, and structurally subordinate to all liabilities of our subsidiaries.

The Notes are redeemable at our option on a make whole basis at any time prior to the date that is one month prior to the maturity of the Notes. On or after the date that is one month prior to the maturity of the Notes, the Notes are redeemable at a redemption price equal to 100% of the principal amount of the Notes to be redeemed.

We incurred costs of $2.9 million in issuing the Notes. These costs included underwriters’ fees, legal and accounting fees, and other fees, and are capitalized and presented as a direct deduction from the principal amount of debt obligations in the consolidated balance sheets. These costs are amortized over the term of the Notes and are included in interest expense in our unaudited condensed consolidated statements of earnings.

EGL Revolving Credit Facility

On August 16, 2018, we and certain of our subsidiaries, as borrowers and guarantors, entered into a new five-year unsecured $600.0 million revolving credit agreement. The credit agreement expires in August 2023 and we have the option to increase the commitments under the facility by up to an aggregate of $400.0 million. Borrowings under the facility will bear interest at a rate based on the Company's long term senior unsecured debt ratings. In connection with our entry into the credit agreement described above, we terminated and fully repaid our previous revolving credit agreement, which was originated on September 16, 2014 and was most recently amended on July 17, 2018.

As at September 30, 2018, we were permitted to borrow up to an aggregate of $600.0 million under the facility. As at September 30, 2018, there was $553.5 million of available unutilized capacity under the facility. Subsequent to September 30, 2018, we repaid $10.0 million, bringing the unutilized capacity under this facility to $563.5 million.

Financial and business covenants imposed on us, in relation to the new revolving credit facility, include certain limitations on mergers and consolidations, acquisitions, indebtedness and guarantees, restrictions as to dispositions of stock and assets, and limitations on liens. Generally, the financial covenants require us to maintain a gearing ratio of consolidated indebtedness to total capitalization of not greater than 0.35 to 1.0 and to maintain a consolidated net worth of not less than the aggregate of (i) $2.3 billion, (ii) 50% of the net income available for distribution to the Company’s ordinary shareholders at any time after June 30, 2018, and (iii) 50% of the proceeds of any common stock issuance by the Company. In addition, we must maintain eligible capital in excess of the enhanced capital requirement imposed on us by the Bermuda Monetary Authority pursuant to the Insurance (Group Supervision) Rules 2011 of Bermuda. We are in compliance with the covenants of the EGL Revolving Credit Facility.

As at September 30, 2018 and December 31, 2017, there were borrowings of €nil and €50.0 million ($60.1 million), respectively, under our revolving credit facilities in effect as of such dates that were designated as non-derivative hedges of our net investment in certain subsidiaries whose functional currency is denominated in Euros. These borrowings were repaid in full during the three months ended September 30, 2018 and the non-derivative hedge was replaced by a Euro-denominated foreign currency forward exchange rate contract in a qualifying hedging arrangement. Refer to Note 8 - "Derivative and Hedging Instruments" for more information on our derivative and non-derivative hedging instruments.

EGL Term Loan Facility

On November 18, 2016, we entered into and fully utilized a three-year $75.0 million unsecured term loan (the "EGL Term Loan Facility"). A portion of the proceeds from the issuance of our Series D Preferred Shares was used to fully repay this facility and the facility was terminated in the three months ended June 30, 2018.

Refer to Note 15 - "Debt Obligations" of the consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2017 for further information on the terms of the above facilities.

Noncontrolling Interests

9 Months Ended

Sep. 30, 2018

Noncontrolling Interest [Abstract]

NONCONTROLLING INTERESTS

15. NONCONTROLLING INTERESTS

Redeemable Noncontrolling Interest

Redeemable noncontrolling interest ("RNCI") as at September 30, 2018 and December 31, 2017 comprises the ownership interests held by the Trident V Funds ("Trident") (39.3%) and Dowling Capital Partners, L.P. ("Dowling") (1.7%) in our subsidiary North Bay Holdings Limited ("North Bay"). North Bay owns our investments in StarStone and Atrium.

The following is a reconciliation of the beginning and ending carrying amount of the equity attributable to the RNCI as at September 30, 2018 and December 31, 2017:



	Nine Months Ended			For The Year Ended
	September 30, 2018			December 31, 2017
Balance at beginning of period	$	479,606		$	454,522
Dividends paid	—			(27,458		)
Net earnings (losses) attributable to RNCI	(20,097		)	19,619
Accumulated other comprehensive earnings (losses) attributable to RNCI	(396		)	1,945
Change in redemption value of RNCI	(785		)	30,978
Balance at end of period	$	458,328		$	479,606

We carried the RNCI at its estimated redemption value, which is fair value, as of September 30, 2018. The decrease was primarily attributable to a decrease in the net assets due to net losses relating to StarStone during the nine months ended September 30, 2018.

Refer to Note 20 - "Related Party Transactions" and Note 21 - "Commitments and Contingencies" for additional information regarding RNCI.

Noncontrolling Interest

As at September 30, 2018 and December 31, 2017, we had $10.3 million and $9.3 million, respectively, of noncontrolling interest ("NCI") related to external interests in two of our non-life run-off subsidiaries.

Share Capital	9 Months Ended
Share Capital	Sep. 30, 2018
Equity [Abstract]
SHARE CAPITAL	16. SHARE CAPITAL Issue of Voting ordinary shares and Series E non-voting ordinary shares On May 14, 2018, an aggregate of 2,007,017 of our ordinary shares were issued to the shareholders of KaylaRe, comprising 1,501,778 voting ordinary shares and 505,239 Series E non-voting ordinary shares. The shares were consideration for the acquisition of KaylaRe Holdings Ltd, as described in Note 2 - "Acquisitions". Issue of Series D Preferred Shares On June 28, 2018, the Company raised $400.0 million through the public offering of 16,000 shares of its 7.00% non-cumulative fixed-to-floating rate Series D perpetual preferred shares ("Series D Preferred Shares") (equivalent to 16,000,000 depositary shares, each of which represents a 1/1,000th interest in a Series D Preferred Share), $1.00 par value and $25,000 liquidation preference (the "Liquidation Preference") per share (equivalent to $25.00 per Depositary Share). After underwriting discounts and other expenses, the Company received net proceeds of $389.2 million which was used to repay a portion of amounts outstanding under the EGL Revolving Credit Facility and repaid in full the EGL Term Loan Facility. The Series D Preferred Shares are not redeemable prior to September 1, 2028, except in specified circumstances relating to certain tax, corporate, capital or rating agency events as described in the prospectus supplement relating to the offering. On and after September 1, 2028, the Series D Preferred Shares, represented by the depositary shares, will be redeemable at the Company’s option, in whole or from time to time in part, at a redemption price equal to $25,000 per Series D Preferred Share (equivalent to $25.00 per depositary share), plus any declared and unpaid dividends. Holders of Series D Preferred Shares will be entitled to receive, only when, as and if declared, non-cumulative cash dividends, paid quarterly in arrears on the 1st day of March, June, September and December of each year, commencing on September 1, 2018, in an amount per share equal to 7.00% of the Liquidation Preference per annum (equivalent to $1,750.00 per Series D Preferred Share and $1.75 per depositary share per annum) up to but excluding September 1, 2028. Commencing on September 1, 2028, which is the commencement date of the floating rate period, quarterly dividends on the Series D Preferred Shares will be payable, on a non-cumulative basis, when, as and if declared, at a floating rate equal to three-month LIBOR plus 4.015% of the Liquidation Preference per annum. Dividends that are not declared will not accumulate and will not be payable. On July 31, 2018, our Board of Directors declared a cash dividend of $320.83 per Series D Preferred share (equivalent to $0.32083 per depositary share), paid on September 1, 2018 to shareholders of record on August 15, 2018. On November 6, 2018 our Board of Directors declared a cash dividend of $437.50 per Series D Preferred share (equivalent to $0.43750 per depositary share), which is payable on December 1, 2018 to shareholders of record on November 15, 2018. Refer to Note 17 - "Share Capital" of the consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2017 for additional information on our share capital.

Earnings Per Share

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

EARNINGS PER SHARE

17. EARNINGS PER SHARE

The following table sets forth the computation of basic and diluted net earnings per ordinary share for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended					Nine Months Ended
	September 30,					September 30,
	2018			2017		2018			2017
Numerator:
Earnings (losses) attributable to Enstar Group Limited ordinary shareholders:
Net earnings (loss) from continuing operations	$	(15,965	)	$	35,498	$	(48,931	)	$	184,864
Net earnings (loss) from discontinued operations	—			3,495		—			(1,005		)
Net earnings (loss) attributable to Enstar Group Limited attributable to Enstar Group Limited ordinary shareholders	(15,965		)	38,993		(48,931		)	183,859
Denominator:
Weighted average ordinary shares outstanding — basic	21,440,914			19,392,120		20,444,634			19,384,897
Effect of dilutive securities:
Share-based compensation plans	143,833			90,118		129,313			58,239
Warrants	80,609			76,930		79,597			72,851
Weighted average ordinary shares outstanding — diluted	21,665,356			19,559,168		20,653,544			19,515,987

Earnings (losses) per ordinary share attributable to Enstar Group Limited:
Basic:
Net earnings (loss) from continuing operations	$	(0.74	)	$	1.83	$	(2.39	)	$	9.54
Net earnings (loss) from discontinued operations	—			0.18		$	—		$	(0.05	)
Net earnings (loss) per ordinary share	$	(0.74	)	$	2.01	$	(2.39	)	$	9.49
Diluted⁽¹⁾:
Net earnings (loss) from continuing operations	$	(0.74	)	$	1.81	$	(2.39	)	$	9.47
Net earnings (loss) from discontinued operations	—			0.18		$	—		$	(0.05	)
Net earnings (loss) per ordinary share	$	(0.74	)	$	1.99	$	(2.39	)	$	9.42

⁽¹⁾During a period of loss, the basic weighted average ordinary shares outstanding is used in the denominator of the diluted loss per ordinary share computation as the effect of including potentially dilutive securities would be anti-dilutive.

Share-Based Compensation and Pensions

9 Months Ended

Sep. 30, 2018

Retirement Benefits [Abstract]

SHARE-BASED COMPENSATION AND PENSIONS

18. SHARE-BASED COMPENSATION AND PENSIONS

We provide various employee benefits including share-based compensation, an employee share purchase plan, an annual incentive compensation program, and pension plans. These are described in Note 19 - "Share-Based Compensation and Pensions" to the consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2017.

The table below provides the expenses related to the share-based compensation plans, employee share purchase plan, and pension plans for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017

Share-based Compensation Expense	$	3,865	$	9,234	$	14,384	$	19,213

Employee Share Purchase Plan	$	115	$	86	$	325	$	252

Pension Expense	$	2,818	$	3,998	$	8,640	$	9,483

Taxation	9 Months Ended
Taxation	Sep. 30, 2018
Income Tax Disclosure [Abstract]
TAXATION	19. TAXATION Interim Tax Calculation Method We use the estimated annual effective tax rate method for computing our interim tax provision. This method applies our best estimate of the effective tax rate expected for the full year to our year-to-date earnings before income taxes. We provide for income tax expense or benefit based upon our pre-tax earnings and the provisions of currently enacted tax laws. Certain items deemed to be unusual, infrequent or not reliably estimated are excluded from the estimated annual effective tax rate. In the event such items are identified, the actual tax expense or benefit is reported in the same period as the related item. Certain other items are not included in the estimated annual effective tax rate, such as changes in the assessment of valuation allowance on deferred tax assets and uncertain tax positions, if any. Interim Tax Expense The effective tax rates on income for the three and nine months ended September 30, 2018 were (3.5)% and (7.8)%, respectively, as compared to 6.5% and 1.6%, respectively for the comparative periods in 2017. The effective tax rate on income differs from the statutory rate of 0% due to tax on foreign operations, primarily the United States and the United Kingdom. We have foreign operating subsidiaries and branch operations principally located in the United States, United Kingdom, Continental Europe and Australia that are subject to federal, foreign, state and local taxes in those jurisdictions. Deferred income tax liabilities have not been accrued with respect to the undistributed earnings of our foreign subsidiaries. If the earnings were to be distributed, as dividends or other distributions, withholding taxes may be imposed by the jurisdiction of the paying subsidiary. For our U.S. subsidiaries, we have not currently accrued any withholding taxes with respect to un-remitted earnings as management has no current intention of remitting these earnings. For our United Kingdom subsidiaries, there are no withholding taxes imposed. For our other foreign subsidiaries, it would not be practicable to compute such amounts due to a variety of factors, including the amount, timing, and manner of any repatriation. Because we operate in many jurisdictions, our net earnings are subject to risk due to changing tax laws and tax rates around the world. The current, rapidly changing economic environment may increase the likelihood of substantial changes to tax laws in the jurisdictions in which we operate. Assessment of Valuation Allowance on Deferred Tax Asset We have estimated the future taxable income of our foreign subsidiaries and have provided a valuation allowance in respect of loss carryforwards where we do not expect to realize a benefit. We have considered all available evidence using a "more than likely than not" standard in determining the amount of the valuation allowance. During the three and nine months ended September 30, 2018, we had no change in our assessment of our valuation allowance on deferred tax assets. Accounting for Uncertainty in Income Taxes There were no unrecognized tax benefits relating to uncertain tax positions as at September 30, 2018 and December 31, 2017. Tax Examinations Our operating subsidiaries may be subject to audit by various tax authorities and may have different statutes of limitations expiration dates. With limited exceptions, our major subsidiaries that operate in the United States, United Kingdom and Australia are no longer subject to tax examinations for years before 2012.

Related Party Transactions

9 Months Ended

Sep. 30, 2018

RELATED PARTY TRANSACTIONS

20. RELATED PARTY TRANSACTIONS

Stone Point Capital LLC

Through several private transactions occurring from May 2012 to July 2012 and an additional private transaction that closed in May 2018, investment funds managed by Stone Point have acquired an aggregate of 1,635,986 of our Voting Ordinary Shares (which now constitutes approximately 9.1% of our outstanding Voting Ordinary Shares). On November 6, 2013, we appointed James D. Carey to our Board of Directors. Mr. Carey is the sole member of an entity that is one of four general partners of the entities serving as general partners for Trident, is a member of the investment committees of such general partners, and is a member and senior principal of Stone Point Capital LLC ("Stone Point"), the manager of the Trident funds.

In addition, we have entered into certain agreements with Trident with respect to Trident’s co-investments in the Atrium, Arden, and StarStone acquisitions. These include investors’ agreements and shareholders’ agreements, which provide for, among other things: (i) our right to redeem Trident’s equity interest in the Atrium/Arden and StarStone transactions in cash at fair market value within the 90 days following September 6, 2018 and April 1, 2019, respectively, and at any time following September 6, 2020 and April 1, 2021, respectively; and (ii) Trident’s right to have its equity co-investment interests in the Atrium/Arden and StarStone transactions redeemed by us at fair market value (which we may satisfy in either cash or our ordinary shares) following September 6, 2020 and April 1, 2021, respectively. Pursuant to the terms of the shareholders’ agreements, Mr. Carey serves as a Trident representative on the boards of the holding companies established in connection with the Atrium/Arden and StarStone co-investment transactions. Trident also has a second representative on these boards who is a Stone Point employee. As at September 30, 2018 and December 31, 2017, the RNCI on our balance sheet relating to these Trident co-investment transactions was as follows:



	September 30, 2018	December 31, 2017
Redeemable Noncontrolling Interest	439,255	459,649

As at September 30, 2018, we had the following relationships with Stone Point and its affiliates:


•	Investments in funds (carried within other investments) managed by Stone Point, with respect to which we recognized unrealized gains and interest income;


•	Investments in registered investment companies affiliated with entities owned by Trident or otherwise affiliated with Stone Point, with respect to which we recognized unrealized gains and interest income;


•	Separate accounts managed by Eagle Point Credit Management and PRIMA Capital Advisors, which are affiliates of entities owned by Trident, with respect to which we incurred management fees;


•	Investments in funds (carried within other investments) managed by Sound Point Capital, an entity in which Mr. Carey has an indirect minority ownership interest and serves as a director, with respect to which we recognized net unrealized gains;


•	Sound Point Capital has acted as collateral manager for certain of our direct investments in CLO equity securities, with respect to which we recognized net unrealized gains (losses) and interest income; and


•	A separate account managed by Sound Point Capital, with respect to which we incurred management fees.

The following table presents the amounts included in our consolidated balance sheet related to our related party transactions with Stone Point and its affiliated entities:



	September 30, 2018		December 31, 2017
Investments in funds managed by Stone Point	$	375,406	$	255,905
Investments in registered investment companies affiliated with entities owned by Trident or Stone Point	34,682		22,060
Investments managed by Eagle Point Credit Management and PRIMA Capital Advisors	252,017		183,448
Investments in funds managed by Sound Point Capital	37,254		27,429
Investments in CLO equity securities with Sound Point Capital as collateral manager	16,206		17,760
Separate account managed by Sound Point Capital	5,231		63,572
Total investments	$	720,796	$	570,174

The following table presents the amounts included in net earnings related to our related party transactions with Stone Point and its affiliated entities:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Net unrealized gains on funds managed by Stone Point	$	9,598		$	6,137		$	11,850		$	17,787
Net unrealized gains (losses) on registered investment companies affiliated with entities owned by Trident or Stone Point	(283		)	86			6,267			5,123
Interest income on registered investment companies affiliated with entities owned by Trident	707			1,138			2,617			2,412
Management fees on investments managed by Eagle Point Credit Management and PRIMA Capital Advisors	(242		)	(160		)	(696		)	(451		)
Net unrealized gains on investments in funds managed by Sound Point Capital	394			576			156			1,370
Net unrealized losses on investments in CLO equity securities with Sound Point Capital as collateral manager	(931		)	(1,090		)	(1,554		)	(3,584		)
Interest income on investments in CLO equity securities with Sound Point Capital as collateral manager	1,106			1,118			3,595			3,598
Management fees on separate account managed by Sound Point Capital	(6		)	(71		)	(167		)	(224		)
Total investment earnings	$	10,343		$	7,734		$	22,068		$	26,031

CPPIB

Canada Pension Plan Investment Board ("CPPIB") owns approximately 8.4% of our voting ordinary shares and additional non-voting shares that, together with its voting ordinary shares held indirectly, represented an economic interest of approximately 17.9% as of September 30, 2018. Poul Winslow, of CPPIB, was appointed to our Board on September 29, 2015 in connection with CPPIB's shareholder rights agreement with us. Approximately 4.1% of our voting ordinary shares are held indirectly by CPPIB through CPPIB Epsilon Ontario Limited Partnership ("CPPIB LP"). CPPIB is the sole limited partner of CPPIB LP. CPPIB Epsilon Ontario Trust ("CPPIB Trust") is the general partner of CPPIB LP, and Mr. Winslow is a trustee of CPPIB Trust. By virtue of his role as a trustee of CPPIB Trust, in its capacity as general partner of CPPIB LP, Mr. Winslow has shared voting and shared dispositive power over the shares, but has no pecuniary interest in the shares.

We also have a pre-existing reinsurance balances recoverable based on normal commercial terms from Continental Assurance Company, a company acquired by Wilton Re Ltd. ("Wilton Re"). CPPIB, together with management of Wilton Re, owns 100% of the common stock of Wilton Re. The reinsurance balances recoverable on our consolidated balance sheet as at September 30, 2018 and December 31, 2017 was as follows:



	September 30, 2018		December 31, 2017
Reinsurance balances recoverable	$	6,884	$	7,003

Hillhouse

Gaoling Fund, L.P., YHG Investment, L.P. and Hillhouse Fund III L.P., investment funds managed by Hillhouse Capital, collectively own approximately 9.7% of Enstar’s voting ordinary shares. These funds also own non-voting ordinary shares and warrants to purchase additional non-voting ordinary shares, which together with their voting ordinary shares, represent an approximate 17.1% economic interest in Enstar. In February 2017, Jie Liu, a Managing Director of Hillhouse Capital, was appointed to our Board. In connection with Hillhouse Capital's investment in KaylaRe, Mr. Liu also served as a director of KaylaRe until resigning from that board in connection with the transaction described above.

As at December 31, 2017, KaylaRe had investments in a fund managed by Hillhouse. On May 14, 2018, KaylaRe was acquired (refer to Note 2 - "Acquisitions" for further details), at which point KaylaRe was consolidated and KaylaRe's investment in Hillhouse InRe Fund, L.P. was recorded within other investments on our consolidated balance sheet.

As at September 30, 2018, we had investments in each of Gaoling Fund, L.P., China Value Fund, L.P. and Hillhouse InRe Fund, L.P., which are funds managed by Hillhouse, with respect to which we recognized unrealized losses.

Our consolidated balance sheet as at September 30, 2018 and December 31, 2017 included the following balances related to transactions between us and Hillhouse and its affiliated entities:



	September 30, 2018		December 31, 2017
Investments in funds managed by Hillhouse, held by equity method investments	$	—	$	456,660

Investment in funds managed by Hillhouse	$	903,568	$	—

The increase in the investment in funds managed by Hillhouse was primarily due to consolidation of the Hillhouse InRe Fund, L.P. which was previously held by KaylaRe, our equity method investee, and additional subscriptions of $445.5 million.

We incurred fees of approximately $8.5 million for the nine months ended September 30, 2018 to Hillhouse and its affiliated entities in relation to the management of the funds described above.

Citco

In June 2018, our subsidiary made a $50.0 million indirect investment in the shares of Citco III Limited ("Citco"), a fund administrator with global operations. Pursuant to an investment agreement and in consideration for participation therein, a related party of Hillhouse Capital provides investment support to our subsidiary. In a private transaction that preceded our co-investment opportunity, certain Citco shareholders, including Trident, agreed to sell all or a portion of their interests in Citco. As of September 30, 2018, Trident owned an approximate 3.4% interest in Citco. Mr. Carey currently serves as an observer to the board of directors of Citco in connection with Trident's investment therein.



	September 30, 2018		December 31, 2017
Investment in Citco	$	49,606	$	—

Monument

Monument was established in October 2016 and Enstar has invested a total of $26.6 million in the common and preferred shares of Monument. We have approximately a 26.6% interest in Monument. In connection with our investment in Monument, we entered into a Shareholders Agreement with the other shareholders. We recorded the investment in Monument using the equity method basis of accounting, as we concluded that we are not required to consolidate based on the guidance in ASC 810 - Consolidation.

On August 29, 2017, we sold our wholly-owned subsidiary Laguna to a subsidiary of Monument, for a total consideration of €25.6 million (approximately $30.8 million). The total loss recorded on the sale of Laguna, for the year ended December 31, 2017 was $16.3 million, which included a cumulative currency translation adjustment balance of $6.3 million, which upon completion of the sale during the third quarter of 2017 was reclassified from accumulated other comprehensive income and included in earnings as a component of the loss on sale of Laguna.

On October 10, 2018, we entered into a Business Transfer Agreement between our wholly-owned subsidiary Alpha Insurance SA and a subsidiary of Monument. This agreement will transfer our remaining life assurance policies to Monument, via a Portfolio Transfer, subject to regulatory approval. The transaction is expected to close in the first half of 2019.

Our investment in the common and preferred shares of Monument, carried in other assets on our consolidated balance sheet, as at September 30, 2018 and December 31, 2017 was as follows:



	September 30, 2018		December 31, 2017
Investment in Monument	$	35,587	$	15,960

Clear Spring (formerly SeaBright)

Effective January 1, 2017, we sold SeaBright Insurance Company (“SeaBright Insurance”) and its licenses to Delaware Life Insurance Company ("Delaware Life"), a subsidiary of Guggenheim Partners, LLC. Following the sale, SeaBright Insurance was renamed Clear Spring Property and Casualty Company (“Clear Spring”). Clear Spring was subsequently capitalized with $56.0 million of equity, with Enstar retaining a 20% indirect equity interest in Clear Spring.

We have recorded the investment in Clear Spring using the equity method basis of accounting, pursuant to the conclusion that we are not required to consolidate following an analysis based on the guidance in ASC 810 - Consolidation. Our investment in the common shares of Clear Spring, carried in other assets on our consolidated balance sheet, as at September 30, 2018 and December 31, 2017 was as follows:



	September 30, 2018		December 31, 2017
Investment in Clear Spring	$	10,565	$	10,596

Effective January 1, 2017, StarStone National Insurance Company (“StarStone National”) entered into a quota share treaty with Clear Spring pursuant to which Clear Spring reinsures 33.3% of core workers compensation business written by StarStone National.

Effective January 1, 2017, Cavello Bay Reinsurance Limited ("Cavello Bay") entered into a quota share treaty with Clear Spring pursuant to which Cavello Bay reinsures 25% of all workers compensation business written by Clear Spring.

Our consolidated balance sheet as at September 30, 2018 and December 31, 2017 included the following balances related to transactions between us and Clear Spring:



	September 30, 2018		December 31, 2017
Balances under StarStone quota share:
Reinsurance balances recoverable	$	19,192	$	9,053
Prepaid insurance premiums	12,215		13,747
Ceded payable	15,275		13,964
Ceded acquisition costs	2,920		3,186

Balances under Cavello Bay quota share:
Losses and LAE	4,682		2,231
Unearned reinsurance premiums	3,054		3,437
Funds held	8,744		5,095

Our consolidated statement of earnings for the three and nine months ended September 30, 2018 and September 30, 2017 included the following amounts related to transactions between us and Clear Spring:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017

Transactions under StarStone quota share:
Ceded premium earned	$	(6,926	)	$	(8,393	)	$	(21,564	)	$	(8,393	)
Ceded incurred losses and LAE	3,823			2,068			12,429			2,068
Ceded acquisition costs	981			5,540			4,892			5,540

Transactions under Cavello Bay quota share:
Premium earned	3,482			2,098			5,391			2,098
Net incurred losses and LAE	(2,346		)	(1,385		)	(3,107		)	(1,385		)
Acquisition costs	(721		)	(1,198		)	(1,275		)	(1,198		)

Net income statement amounts	$	(1,707	)	$	(1,270	)	$	(3,234	)	$	(1,270	)

AmTrust

Effective July 23, 2018 the Company entered into a Subscription Agreement with Evergreen Parent L.P. ("Evergreen"), K-Z Evergreen, LLC and Trident Pine Acquisition LP ("Trident Pine"). Evergreen is an entity formed by private equity funds managed by Stone Point and the Karfunkel-Zyskind family that intends to acquire approximately 45% of the issued and outstanding shares of common stock of AmTrust Financial Services, Inc. ("AmTrust") that the Karfunkel-Zyskind Family and certain of its affiliates and related parties do not presently own or control. The transaction was approved by AmTrust’s stockholders on June 21, 2018, and is expected to close during the fourth quarter of 2018, subject to the satisfaction of customary closing conditions, including approval by regulatory authorities.

Pursuant to the Subscription Agreement, and subject to the conditions therein, we agreed to purchase equity in Evergreen in the aggregate amount of $200.0 million. The equity interest will be in the form of three separate classes of equity securities issued at the same price and in the same proportion as the equity interest to be purchased by Trident Pine. Following the closing of the transaction, Enstar is expected to own approximately 7.4% of the capital units of Evergreen. Among other conditions, the closing under the Subscription Agreement is contingent on the closing of Evergreen’s transaction with respect to AmTrust.

KaylaRe

On May 14, 2018, the Company completed the previously announced transaction to acquire all of the outstanding shares and warrants of KaylaRe, following the receipt of all required regulatory approvals. In consideration for the acquired shares and warrants of KaylaRe, the Company issued an aggregate of 2,007,017 ordinary shares, comprising 1,501,778 voting ordinary shares and 505,239 Series E non-voting ordinary shares to the shareholders of KaylaRe as follows: (i) 1,204,353 voting ordinary shares and 505,239 Series E Shares to a fund managed by Hillhouse Capital; (ii) 285,986 voting ordinary shares to Trident; and (iii) 11,439 voting ordinary shares to the minority shareholder. In addition, the Shareholders Agreement between Enstar and the other KaylaRe shareholders was effectively terminated. Effective May 14, 2018 we consolidated KaylaRe into our consolidated financial statements and any balances between KaylaRe and Enstar are now eliminated upon consolidation. Refer to Note 2 - "Acquisitions" for additional information.

On December 15, 2016, KaylaRe completed an initial capital raise of $620.0 million. We originally owned approximately 48.2% of KaylaRe's common shares and recorded our investment in KaylaRe using the equity method basis of accounting, pursuant to the conclusion that we were not required to consolidate following an analysis based on the guidance in ASC 810 - Consolidation. Our investment in the common shares and warrants of KaylaRe was carried at $320.1 million and $309.8 million in other assets on our consolidated balance sheet as at May 14, 2018 and December 31, 2017, respectively.

Our subsidiary, Enstar Limited, acts as insurance and reinsurance manager to KaylaRe's subsidiary, KaylaRe Ltd., for which it received fee income. Affiliates of Enstar have also entered into various reinsurance agreements with KaylaRe Ltd. We provide administrative services to KaylaRe and KaylaRe Ltd.

Through a Quota Share Agreement dated December 15, 2016 (the "KaylaRe-StarStone QS"), several of our StarStone affiliates have entered into a Quota Share Treaty with KaylaRe Ltd. pursuant to which KaylaRe Ltd. reinsures 35% of all business written by these StarStone affiliates for risks attaching from January 1, 2016, net of the StarStone affiliates’ external reinsurance programs. As of January 1, 2018, the reinsurance of StarStone's U.S. entities was non-renewed.

In addition, Fitzwilliam Insurance Limited ("Fitzwilliam"), one of our non-life run-off subsidiaries, ceded $177.2 million of loss reserves to KaylaRe Ltd. in 2016. Under the terms of this reinsurance agreement, Fitzwilliam is entitled to receive a profit commission calculated with reference to reserve savings made during the currency of this agreement. Our Non-life Run-off subsidiaries did not cede any additional business to KaylaRe Ltd. during three and nine months ended September 30, 2018 and 2017.

Our consolidated balance sheet as at December 31, 2017 included the following balances related to transactions between us and KaylaRe and KaylaRe Ltd.:



	December 31, 2017
Reinsurance balances recoverable	$	357,355
Prepaid reinsurance premiums	116,356
Funds held	174,181
Insurance and reinsurance balances payable	232,884
Ceded acquisition costs	36,070

Our consolidated statement of earnings for the nine months ended September 30, 2018 (prior to consolidation) and September 30, 2017 included the following amounts related to transactions between us and KaylaRe and KaylaRe Ltd.:



	Nine Months Ended
	September 30,
	2018			2017
Management fee income	$	1,453		$	6,059

Transactions under KaylaRe-StarStone QS:
Ceded premium earned	(52,651		)	(170,552		)
Net incurred losses	31,654			127,578
Acquisition costs	18,774			67,375

Transactions under Fitzwilliam reinsurance agreement:
Profit Commission	—			11,525
Net incurred losses	—			(12,791		)

Net income statement gain (loss) amounts	$	(770	)	$	29,194

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	21. COMMITMENTS AND CONTINGENCIES Concentrations of Credit Risk We believe that there are no significant concentrations of credit risk associated with our cash and cash equivalents, fixed maturity investments, or other investments. Cash, cash equivalents and fixed maturity investments are managed pursuant to guidelines that follow prudent standards of diversification and limit the allowable holdings of a single issue and issuers. Other investments are managed pursuant to guidelines that emphasize diversification and liquidity. Pursuant to these guidelines, we manage and monitor risk across a variety of investment funds and vehicles, markets and counterparties. We are also subject to custodial credit risk on our investments, which we manage by diversifying our holdings amongst large financial institutions that are highly regulated. We have exposure to credit risk on certain of our assets pledged to ceding companies under insurance contracts. In addition, we are potentially exposed should any insurance intermediaries be unable to fulfill their contractual obligations with respect to payments of balances owed to and by us. Credit risk exists in relation to reinsurance balances recoverable. We remain liable to the extent that retrocessionaires do not meet their contractual obligations and, therefore, we evaluate and monitor concentration of credit risk among our reinsurers. These amounts are discussed in Note 9 - "Reinsurance Balances Recoverable". We are also subject to credit risk in relation to funds held by reinsured companies. Under funds held arrangements, the reinsured company has retained funds that would otherwise have been remitted to our reinsurance subsidiaries. The funds balance is credited with investment income and losses payable are deducted. We are subject to credit risk if the reinsured company is unable to honor the value of the funds held balances, such as in the event of insolvency. However, we generally have the contractual ability to offset any shortfall in the payment of the funds held balances with amounts owed by us to the reinsured for losses payable and other amounts contractually due. We routinely monitor the creditworthiness of reinsured companies with whom we have funds held arrangements. We have a significant concentration of $1,037.6 million to one reinsured company which has financial strength credit ratings of A+ from A.M. Best and AA from Standard & Poor's. We limit the amount of credit exposure to any one counterparty, and none of our counterparty credit exposures, excluding U.S. government instruments and the funds held counterparty noted above, exceeded 10% of shareholders’ equity as at September 30, 2018. Our credit exposure to the U.S. government was $787.9 million as at September 30, 2018. Legal Proceedings We are, from time to time, involved in various legal proceedings in the ordinary course of business, including litigation and arbitration regarding claims. Estimated losses relating to claims arising in the ordinary course of business, including the anticipated outcome of any pending arbitration or litigation, are included in the liability for losses and LAE in our consolidated balance sheets. In addition to claims litigation, we may be subject to other lawsuits and regulatory actions in the normal course of business, which may involve, among other things, allegations of underwriting errors or omissions, employment claims or regulatory activity. We do not believe that the resolution of any currently pending legal proceedings, either individually or taken as a whole, will have a material effect on our business, results of operations or financial condition. We anticipate that, similar to the rest of the insurance and reinsurance industry, we will continue to be subject to litigation and arbitration proceedings in the ordinary course of business, including litigation generally related to the scope of coverage with respect to asbestos and environmental and other claims. Unfunded Investment Commitments As at September 30, 2018, we had total unfunded investment commitments to private equity funds of $200.0 million and commitments of $200.0 million related to our investment in AmTrust as discussed in Note 20 - "Related Party Transactions". Guarantees As at September 30, 2018 and December 31, 2017, parental guarantees and capital instruments supporting subsidiaries' policyholder obligations were $620.0 million and $630.7 million, respectively. On February 8, 2018, we amended and restated the FAL Facility to issue up to $325.0 million of letters of credit, with a provision to increase the facility up to $400.0 million. The FAL Facility is available to satisfy our Funds at Lloyd’s requirements and expires in 2022. As at September 30, 2018, there were $295.0 million in letters of credit issued under this facility which have a parental guarantee. Asbestos Personal Injury Liabilities We acquired Dana Companies, LLC ("Dana") on December 30, 2016, as described in Note 3 - "Acquisitions" of our consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2017. Dana continues to process asbestos personal injury claims in the normal course of business and is separately managed. Other liabilities included $187.9 million and $205.7 million for indemnity and defense costs for pending and future claims at September 30, 2018 and December 31, 2017, respectively, determined using standard actuarial techniques for asbestos-related exposures. Other liabilities also included $2.1 million and $2.2 million for environmental liabilities associated with Dana properties at September 30, 2018 and December 31, 2017, respectively. Other assets included $114.8 million and $122.3 million at September 30, 2018 and December 31, 2017, respectively, for estimated insurance recoveries relating to these liabilities. The recorded asset represents our assessment of the capacity of the insurance agreements to provide for the payment of anticipated defense and indemnity costs for pending claims and projected future demands. The recognition of these recoveries is based on an assessment of the right to recover under the respective contracts and on the financial strength of the insurers. The recorded asset does not represent the limits of our insurance coverage, but rather the amount we would expect to recover if the accrued indemnity and defense costs were paid in full. Redeemable Noncontrolling Interest We have the right to purchase the RNCI interests from the RNCI holders at certain times in the future (each such right, a "call right"), and the RNCI holders have the right to sell their RNCI interests to us at certain times in the future (each such right, a "put right"). The RNCI rights held by Trident are described in Note 20 - "Related Party Transactions". Dowling has a right to participate if Trident exercises its put right.

Segment Information

9 Months Ended

Sep. 30, 2018

Segment Reporting [Abstract]

SEGMENT INFORMATION

22. SEGMENT INFORMATION

In the second half of 2017, following the completion of the sale of our Laguna and Pavonia businesses, which significantly reduced the size of our life and annuities business, we undertook a review of our reportable segments. Following this review we determined that we have three reportable segments of business that are each managed, operated and reported on separately: (i) Non-life Run-off; (ii) Atrium; and (iii) StarStone. Our other activities, which do not qualify as a reportable segment, include our corporate expenses, debt servicing costs, holding company income and expenses, foreign exchange, our remaining life business and other miscellaneous items. The change in reportable segments had no impact on our previously reported historical consolidated financial positions, results of operations or cash flows. These segments are described in Note 1 - "Description of Business" and Note 24 - "Segment Information" to the consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2017.

The following tables set forth selected and unaudited condensed consolidated statement of earnings results by segment for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended September 30, 2018
	Non-Life Run-Off			Atrium			StarStone			Other			Total
Gross premiums written	$	9,912		$	39,995		$	282,525		$	846		$	333,278

Net premiums written	$	4,778		$	37,141		$	219,726		$	822		$	262,467

Net premiums earned	$	10,442		$	36,977		$	216,355		$	823		$	264,597
Net incurred losses and LAE	62,778			(17,853		)	(198,899		)	—			(153,974		)
Life and Annuity Policy Benefits	—			—			—			(423		)	(423		)
Acquisition costs	160			(13,215		)	(41,079		)	(108		)	(54,242		)
Operating expenses	(37,473		)	(3,952		)	(38,000		)	—			(79,425		)
Underwriting income (loss)	35,907			1,957			(61,623		)	292			(23,467		)
Net investment income	59,247			1,597			9,504			(918		)	69,430
Net realized and unrealized gains (losses)	(58,506		)	194			989			100			(57,223		)
Fees and commission income	3,708			3,242			—			—			6,950
Other income (expense)	11,423			7			117			(4		)	11,543
Corporate expenses	(11,433		)	(2,770		)	—			(8,925		)	(23,128		)
Interest income (expense)	(5,951		)	—			—			1,311			(4,640		)
Net foreign exchange gains (losses)	17			(262		)	(585		)	(210		)	(1,040		)
EARNINGS (LOSS) BEFORE INCOME TAXES	34,412			3,965			(51,598		)	(8,354		)	(21,575		)
INCOME (TAXES) BENEFIT	(125		)	(737		)	118			(2		)	(746		)
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	34,287			3,228			(51,480		)	(8,356		)	(22,321		)
Net loss (earnings) attributable to noncontrolling interest	(1,659		)	(1,266		)	14,414			—			11,489
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	32,628			1,962			(37,066		)	(8,356		)	(10,832		)
Dividends on preferred shares	—			—			—			(5,133		)	(5,133		)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$	32,628		$	1,962		$	(37,066	)	$	(13,489	)	$	(15,965	)

Underwriting ratios⁽¹⁾:
Loss ratio				48.3		%	91.9		%
Acquisition expense ratio				35.7		%	19.0		%
Operating expense ratio				10.7		%	17.6		%
Combined ratio				94.7		%	128.5		%

⁽¹⁾Refer to "Underwriting Ratios" for a description of how these ratios are calculated.



	Nine Months Ended September 30, 2018
	Non-Life Run-Off			Atrium			StarStone			Other			Total
Gross premiums written	$	16,354		$	130,997		$	888,867		$	2,858		$	1,039,076

Net premiums written	$	3,217		$	113,218		$	619,528		$	2,871		$	738,834

Net premiums earned	$	27,229		$	106,722		$	526,802		$	2,875		$	663,628
Net incurred losses and LAE	205,890			(51,951		)	(420,266		)	—			(266,327		)
Life and Annuity Policy Benefits	—			—			—			(217		)	(217		)
Acquisition costs	(4,524		)	(37,996		)	(94,775		)	(389		)	(137,684		)
Operating expenses	(114,254		)	(12,259		)	(106,699		)	—			(233,212		)
Underwriting income (loss)	114,341			4,516			(94,938		)	2,269			26,188
Net investment income	168,189			4,067			25,950			4,012			202,218
Net realized and unrealized losses	(230,829		)	(1,889		)	(15,150		)	(6,803		)	(254,671		)
Fees and commission income	13,093			10,540			—			—			23,633
Other income (expense)	34,989			127			(432		)	(207		)	34,477
Corporate expenses	(33,453		)	(5,083		)	—			(28,677		)	(67,213		)
Interest income (expense)	(24,562		)	—			(547		)	3,536			(21,573		)
Net foreign exchange gains (losses)	(202		)	(1,262		)	(1,063		)	1,138			(1,389		)
EARNINGS (LOSS) BEFORE INCOME TAXES	41,566			11,016			(86,180		)	(24,732		)	(58,330		)
INCOME TAXES	(227		)	(1,756		)	(2,568		)	(13		)	(4,564		)
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	41,339			9,260			(88,748		)	(24,745		)	(62,894		)
Net loss (earnings) attributable to noncontrolling interest	(4,182		)	(3,798		)	27,076			—			19,096
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	37,157			5,462			(61,672		)	(24,745		)	(43,798		)
Dividends on preferred shares	—			—			—			(5,133		)	(5,133		)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$	37,157		$	5,462		$	(61,672	)	$	(29,878	)	$	(48,931	)

Underwriting ratios⁽¹⁾:
Loss ratio				48.7		%	79.8		%
Acquisition expense ratio				35.6		%	18.0		%
Operating expense ratio				11.5		%	20.2		%
Combined ratio				95.8		%	118.0		%

⁽¹⁾Refer to "Underwriting Ratios" for a description of how these ratios are calculated.



	Three Months Ended September 30, 2017
	Non-Life Run-Off			Atrium			StarStone			Other			Total
Gross premiums written	$	11,751		$	36,377		$	200,007		$	2,424		$	250,559

Net premiums written	$	11,467		$	25,989		$	97,049		$	1,671		$	136,176

Net premiums earned	$	6,415		$	32,773		$	107,650		$	1,187		$	148,025
Net incurred losses and LAE	70,882			(35,273		)	(111,321		)	—			(75,712		)
Life and Annuity Policy Benefits	—			—			—			(1,060		)	(1,060		)
Acquisition costs	(1,001		)	(11,818		)	(11,313		)	(149		)	(24,281		)
Operating expenses	(35,657		)	(2,507		)	(32,605		)	—			(70,769		)
Underwriting income (loss)	40,639			(16,825		)	(47,589		)	(22		)	(23,797		)
Net investment income	42,829			847			7,592			760			52,028
Net realized and unrealized gains (losses)	25,016			285			5,045			(1,045		)	29,301
Fees and commission income (expense)	10,762			5,911			—			(778		)	15,895
Other income (expense)	(4,018		)	69			91			10			(3,848		)
Corporate expenses	(20,326		)	37			—			(9,267		)	(29,556		)
Interest income (expense)	(6,664		)	(23		)	(382		)	659			(6,410		)
Net foreign exchange gains (losses)	(3,772		)	(43		)	1,145			(2,105		)	(4,775		)
Loss on sale of subsidiary	—			—			—			(6,740		)	(6,740		)
EARNINGS (LOSS) BEFORE INCOME TAXES	84,466			(9,742		)	(34,098		)	(18,528		)	22,098
INCOME (TAXES) BENEFIT	(970		)	(554		)	78			14			(1,432		)
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	83,496			(10,296		)	(34,020		)	(18,514		)	20,666
NET EARNINGS FROM DISCONTINUED OPERATIONS, NET OF INCOME TAX EXPENSE	—			—			—			3,495			3,495
NET EARNINGS (LOSS)	83,496			(10,296		)	(34,020		)	(15,019		)	24,161
Net loss (earnings) attributable to noncontrolling interest	(3,314		)	4,223			13,923			—			14,832
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$	80,182		$	(6,073	)	$	(20,097	)	$	(15,019	)	$	38,993

Underwriting ratios⁽¹⁾:
Loss ratio				107.6		%	103.4		%
Acquisition expense ratio				36.1		%	10.5		%
Operating expense ratio				7.6		%	30.3		%
Combined ratio				151.3		%	144.2		%

⁽¹⁾Refer to "Underwriting Ratios" for a description of how these ratios are calculated.



	Nine Months Ended September 30, 2017
	Non-Life Run-Off			Atrium			StarStone			Other			Total
Gross premiums written	$	13,956		$	117,355		$	651,107		$	4,506		$	786,924

Net premiums written	$	13,453		$	99,235		$	331,449		$	3,646		$	447,783

Net premiums earned	$	9,856		$	97,373		$	341,609		$	3,656		$	452,494
Net incurred losses and LAE	138,041			(55,950		)	(245,315		)	—			(163,224		)
Life and Annuity Policy Benefits	—			—			—			(5,048		)	(5,048		)
Acquisition costs	(455		)	(34,647		)	(39,625		)	(730		)	(75,457		)
Operating expenses	(96,767		)	(12,227		)	(99,576		)	—			(208,570		)
Underwriting income (loss)	50,675			(5,451		)	(42,907		)	(2,122		)	195
Net investment income	118,130			2,832			20,230			8,992			150,184
Net realized and unrealized gains (losses)	127,130			1,177			18,953			(7,563		)	139,697
Fees and commission income (expense)	30,302			17,353			1,166			(2,345		)	46,476
Other income	18,679			188			170			169			19,206
Corporate expenses	(66,468		)	(7,404		)	—			(26,841		)	(100,713		)
Interest income (expense)	(20,991		)	(559		)	(1,648		)	2,347			(20,851		)
Net foreign exchange losses	(6,709		)	(4,355		)	(1,563		)	(2,985		)	(15,612		)
Loss on sale of subsidiary	—			—			—			(16,349		)	(16,349		)
EARNINGS (LOSS) BEFORE INCOME TAXES	250,748			3,781			(5,599		)	(46,697		)	202,233
INCOME (TAXES) BENEFIT	(5,609		)	(1,278		)	3,648			5			(3,234		)
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	245,139			2,503			(1,951		)	(46,692		)	198,999
NET LOSS FROM DISCONTINUED OPERATIONS, NET OF INCOME TAX EXPENSE	—			—			—			(1,005		)	(1,005		)
NET EARNINGS (LOSS)	245,139			2,503			(1,951		)	(47,697		)	197,994
Net loss (earnings) attributable to noncontrolling interest	(13,944		)	(1,027		)	836			—			(14,135		)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$	231,195		$	1,476		$	(1,115	)	$	(47,697	)	$	183,859

Underwriting ratios⁽¹⁾:
Loss ratio				57.5		%	71.8		%
Acquisition expense ratio				35.6		%	11.6		%
Operating expense ratio				12.5		%	29.2		%
Combined ratio				105.6		%	112.6		%

⁽¹⁾Refer to "Underwriting Ratios" for a description of how these ratios are calculated.

Assets by Segment

Invested assets are managed on a subsidiary-by-subsidiary basis, and investment income and realized and unrealized gains (losses) on investments are recognized in each segment as earned. Our total assets as at September 30, 2018 and December 31, 2017 by segment were as follows:



	September 30,			December 31,
	2018			2017
Assets by Segment:
Non-life Run-off	$	11,907,196		$	10,368,105
Atrium	598,072			556,637
StarStone	3,199,238			3,128,725
Other	(583,278		)	(447,045		)
Total assets	$	15,121,228		$	13,606,422

Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Basis of Preparation

Basis of Consolidation

Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, these financial statements reflect all adjustments consisting of normal recurring items considered necessary for a fair presentation under U.S. GAAP. The results of operations for any interim period are not necessarily indicative of results of the full year. These financial statements should be read in conjunction with the consolidated financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2017. All significant inter-company transactions and balances have been eliminated. In these notes, the terms "we," "us," "our," or "the Company" refer to Enstar Group Limited and its consolidated subsidiaries.

Reclassifications

Certain prior period amounts have been reclassified to conform to the current period presentation. These reclassifications had no impact on net earnings.

Use of Estimates


•	liability for losses and loss adjustment expenses ("LAE");


•	liability for policy benefits for life contracts;


•	reinsurance balances recoverable;


•	gross and net premiums written and net premiums earned;


•	impairment charges, including other-than-temporary impairments on investment securities classified as available-for-sale, and impairments on goodwill, intangible assets and deferred charges;


•	fair value measurements of investments;


•	fair value estimates associated with accounting for acquisitions;


•	fair value estimates associated with loss portfolio transfer reinsurance agreements for which we have elected the fair value option; and


•	redeemable noncontrolling interests.

New Accounting Standards Adopted and Recently Issued Accounting Pronouncements Not Yet Adopted

New Accounting Standards Adopted in 2018

Accounting Standards Update ("ASU") 2017-09, Stock Compensation - Scope of Modification Accounting

ASU 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost

ASU 2017-05, Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets

ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory

ASU 2016-15, Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payments

ASU 2016-01, Recognition and Measurement of Financial Instruments

ASUs 2014-09, 2016-08, 2016-10, 2016-12, Revenue from Contracts with Customers

Recently Issued Accounting Pronouncements Not Yet Adopted

ASU 2018-17, Targeted Improvements to Related Party Guidance for Variable Interest Entities

ASU 2018-13, Changes to the Disclosure Requirements for Fair Value Measurements

ASU 2018-12, Targeted Improvements to the Accounting for Certain Long-Duration Insurance Contracts

ASU 2018-11, Targeted Improvements to ASC 842 - Leases and ASU 2018-10, Codification Improvements to ASC 842 - Leases

ASU 2018-09, Codification Improvements

Acquisitions (Tables)

9 Months Ended

Sep. 30, 2018

Business Combinations [Abstract]

Schedule of Acquisitions



Number of Enstar Ordinary shares issued	2,007,017
Closing price of Enstar Ordinary shares as of May 14, 2018	$	206.65
Fair value of Enstar Ordinary shares issued to shareholders of KaylaRe	$	414,750



Carrying value of previously held equity method investment prior to the close of the transaction	$	320,130
Price-to-book multiple	1.05
Fair value of previously held equity method investment prior to the close of the transaction	$	336,137

Gain recognized on remeasurement of previously held equity method investment to fair value	$	16,007

Purchase Price

The components of the consideration paid to acquire all of the outstanding shares and warrants of KaylaRe were as follows:



Fair value of Enstar ordinary shares issued	$	414,750
Fair value of previously held equity method investment	336,137
Adjustment for the fair value of preexisting relationships	37,169
Total purchase price	$	788,056
Net assets acquired at fair value (excluding preexisting relationships)	$	746,320
Excess of purchase price over fair value of net assets acquired	$	41,736



ASSETS	Carrying value			Fair value			Loss on deemed settlement
Funds held by reinsured companies	$	386,793		$	386,793		$	—
Deferred acquisition costs/Value of business acquired	33,549			40,268			6,719
TOTAL ASSETS	420,342			427,061			6,719
LIABILITIES
Losses and LAE	339,747			333,205			(6,542		)
Unearned premiums	105,602			105,602			—
Insurance and reinsurance balances payable	25,897			23,559			(2,338		)
Other liabilities	1,864			1,864			—
TOTAL LIABILITIES	473,110			464,230			(8,880		)
NET ASSETS (LIABILITIES)	$	(52,768	)	$	(37,169	)	$	15,599

Fair Values of Assets Acquired and Liabilities Assumed



ASSETS
Fixed maturities, trading, at fair value	$	126,393
Other investments, at fair value	626,476
Total investments	752,869
Cash and cash equivalents	5,657
Premiums receivable	10,965
Deferred acquisition costs	275
Other assets	614
TOTAL ASSETS	$	770,380
LIABILITIES
Losses and LAE	$	4,059
Unearned premiums	10,984
Insurance and reinsurance balances payable	13
Other liabilities	9,004
TOTAL LIABILITIES	24,060
NET ASSETS ACQUIRED AT FAIR VALUE	$	746,320

Results of Operations of Acquiree

The table below summarizes the results of the KaylaRe operations which are included in our condensed consolidated statement of earnings from the acquisition date to September 30, 2018:



Premiums earned	$	10,188
Incurred losses and LAE	(9,190		)
Acquisition costs	(332		)
Underwriting income	666
Net investment income	1,972
Net unrealized gains	(6,621		)
General and administrative expenses	(573		)
Net loss	$	(4,556	)

Divestitures, Held-For-Sale Businesses and Discontinued Operations (Tables)

9 Months Ended

Sep. 30, 2018

Discontinued Operations and Disposal Groups [Abstract]

Financial Information of Held-For-Sale Business

The following table summarizes the components of assets and liabilities held-for-sale on our consolidated balance sheet as at December 31, 2017:



	December 31, 2017
Assets:
Fixed maturities, trading, at fair value	$	20,770
Equities, trading, at fair value	765
Cash and cash equivalents	6,314
Restricted cash and cash equivalents	13
Reinsurance balances recoverable	1,728
Other assets	269
Assets of businesses held for sale	29,859
Less: Accrual of loss on sale	(5,508		)
Total assets held for sale	$	24,351

Liabilities:
Policy benefits for life and annuity contracts	$	10,666
Other liabilities	605
Total liabilities held-for-sale	$	11,271

The following table summarizes the components of net earnings from discontinued operations on the unaudited condensed consolidated statements of earnings for the three and nine months ended September 30, 2017:



	Three Months Ended			Nine Months Ended
	September 30,			September 30,
	2017			2017
INCOME
Net premiums earned	$	14,082		$	42,012
Net investment income	10,077			30,383
Net realized and unrealized gains (losses)	(233		)	2,543
Other income	384			1,139
	24,310			76,077
EXPENSES
Life and annuity policy benefits	15,320			60,102
Acquisition costs	2,412			6,728
General and administrative expenses	2,809			9,584
Other expenses	4			(12		)
	20,545			76,402
EARNINGS (LOSSES) BEFORE INCOME TAXES	3,765			(325		)
INCOME TAXES	(270		)	(680		)
NET EARNINGS (LOSS) FROM DISCONTINUED OPERATIONS	$	3,495		$	(1,005	)

The following table presents the cash flows of Pavonia for the nine months ended September 30, 2017:



	Nine Months Ended September 30,
	2017
Operating activities	$	42,558
Investing activities	8,129
Change in cash of businesses held-for-sale	$	50,687

- Definition

Tabular disclosure of information related to a disposal group. Includes, but is not limited to, a discontinued operation, disposal classified as held-for-sale or disposed of by means other than sale or disposal of an individually significant component.

+ References

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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

Investments (Tables)

9 Months Ended

Sep. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Estimated Fair Values of Investments in Fixed Maturity Investments, Short-Term Investments and Equities, Trading Securities

The fair values of our fixed maturity investments, short-term investments and equities classified as trading were as follows:



	September 30, 2018		December 31, 2017
U.S. government and agency	$	493,080	$	554,036
Non-U.S. government	1,018,212		607,132
Corporate	3,703,029		3,363,060
Municipal	76,599		100,221
Residential mortgage-backed	275,485		288,713
Commercial mortgage-backed	411,575		421,548
Asset-backed	567,300		541,574
Total fixed maturity and short-term investments	6,545,280		5,876,284
Equities — U.S.	72,765		106,363
Equities — International	57,549		240
	$	6,675,594	$	5,982,887

Summary of Amortized Cost and Estimated Fair Value of Fixed Maturities by Contractual Maturity



As at September 30, 2018	Amortized Cost		Fair Value		% of Total Fair Value
One year or less	$	428,656	$	424,195	6.5	%
More than one year through two years	544,754		531,717		8.1	%
More than two years through five years	1,641,037		1,601,237		24.4	%
More than five years through ten years	1,506,829		1,464,185		22.4	%
More than ten years	1,301,979		1,269,586		19.4	%
Residential mortgage-backed	274,833		275,485		4.2	%
Commercial mortgage-backed	423,471		411,575		6.3	%
Asset-backed	567,538		567,300		8.7	%
	$	6,689,097	$	6,545,280	100.0	%



As at September 30, 2018	Amortized Cost		Fair Value		% of Total Fair Value
One year or less	$	18,265	$	17,641	10.8	%
More than one year through two years	26,556		26,332		16.2	%
More than two years through five years	31,604		31,634		19.4	%
More than five years through ten years	55,804		55,818		34.2	%
More than ten years	31,452		31,704		19.4	%
Residential mortgage-backed	15		15		—	%
	$	163,696	$	163,144	100.0	%

Amortized Cost and Estimated Fair Values of Company's Fixed Maturity and Short-Term Investments Classified as Available-for-Sale

The amortized cost and fair values of our fixed maturity investments classified as available-for-sale were as follows:



As at September 30, 2018	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses (Non-OTTI)			Fair Value
U.S. government and agency	$	703	$	—	$	(5	)	$	698
Non-U.S. government	75,741		851		(1,036		)	75,556
Corporate	83,836		1,085		(1,413		)	83,508
Municipal	3,401		—		(34		)	3,367
Residential mortgage-backed	15		—		—			15
	$	163,696	$	1,936	$	(2,488	)	$	163,144



As at December 31, 2017	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses (Non-OTTI)			Fair Value
U.S. government and agency	$	4,210	$	—	$	(23	)	$	4,187
Non-U.S. government	84,776		1,249		(588		)	85,437
Corporate	113,561		2,436		(876		)	115,121
Municipal	5,146		8		(18		)	5,136
Residential mortgage-backed	31		—		—			31
Asset-backed	373		—		—			373
	$	208,097	$	3,693	$	(1,505	)	$	210,285

Summary of Investments Classified as Available-for-Sale in Unrealized Loss Position as Well as Aggregate Fair Value and Gross Unrealized Loss by Length of Time

The following tables summarize our fixed maturity investments classified as available-for-sale that are in a gross unrealized loss position:



	12 Months or Greater					Less Than 12 Months					Total
As at September 30, 2018	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Fixed maturity investments, at fair value
U.S. government and agency	$	698	$	(5	)	$	—	$	—		$	698	$	(5	)
Non-U.S. government	4,233		(406		)	21,719		(630		)	25,952		(1,036		)
Corporate	8,562		(917		)	33,808		(496		)	42,370		(1,413		)
Municipal	617		(12		)	2,750		(22		)	3,367		(34		)
Total fixed maturity investments	$	14,110	$	(1,340	)	$	58,277	$	(1,148	)	$	72,387	$	(2,488	)



	12 Months or Greater					Less Than 12 Months					Total
As at December 31, 2017	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Fixed maturity investments, at fair value
U.S. government and agency	$	2,344	$	(16	)	$	1,842	$	(7	)	$	4,186	$	(23	)
Non-U.S. government	11,101		(373		)	20,965		(215		)	32,066		(588		)
Corporate	9,177		(807		)	24,200		(69		)	33,377		(876		)
Municipal	369		(5		)	3,605		(13		)	3,974		(18		)
Total fixed maturity investments	$	22,991	$	(1,201	)	$	50,612	$	(304	)	$	73,603	$	(1,505	)

Credit Ratings Company's Fixed Maturity and Short-Term Investments Available-for-Sale

The following table sets forth the credit ratings of our fixed maturity (including both trading and available-for-sale investments) and short-term investments as at September 30, 2018:



	Amortized Cost		Fair Value		% of Total Investments		AAA Rated			AA Rated			A Rated			BBB Rated			Non- Investment Grade			Not Rated
Fixed maturity and short-term investments
U.S. government and agency	$	502,168	$	493,778	7.4	%	$	489,939		$	3,839		$	—		$	—		$	—		$	—
Non-U.S. government	1,109,697		1,093,768		16.3	%	340,583			541,087			65,286			121,197			25,615			—
Corporate	3,893,368		3,786,537		56.4	%	154,961			445,858			1,986,880			1,016,401			180,730			1,707
Municipal	81,703		79,966		1.2	%	8,739			53,094			14,277			3,856			—			—
Residential mortgage-backed	274,848		275,500		4.1	%	163,190			2,526			11,331			1,540			92,180			4,733
Commercial mortgage-backed	423,471		411,575		6.1	%	210,902			47,118			70,164			60,296			9,936			13,159
Asset-backed	567,538		567,300		8.5	%	237,239			46,971			115,349			73,415			93,918			408
Total	$	6,852,793	$	6,708,424	100.0	%	$	1,605,553		$	1,140,493		$	2,263,287		$	1,276,705		$	402,379		$	20,007
% of total fair value							23.9		%	17.0		%	33.8		%	19.0		%	6.0		%	0.3		%

Other Investments

The following table summarizes our other investments carried at fair value:



	September 30, 2018		December 31, 2017
Private equities and private equity funds	$	256,618	$	289,556
Fixed income funds	383,328		229,999
Hedge funds	879,571		63,773
Equity funds	381,983		249,475
CLO equities	48,368		56,765
CLO equity fund	41,501		12,840
Private credit funds	39,751		10,156
Call options on equity	4,590		—
Other	720		828
	$	2,036,430	$	913,392

Major Categories of Net Investment Income

Major categories of net investment income for the three and nine months ended September 30, 2018 and 2017 are summarized as follows:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Fixed maturity investments	$	48,062		$	37,931		$	140,097		$	102,002
Short-term investments and cash and cash equivalents	3,247			2,048			8,425			7,489
Funds held	1,502			247			8,651			597
Funds held - directly managed	9,776			8,516			27,990			24,121
Investment income from fixed maturities and cash and cash equivalents	62,587			48,742			185,163			134,209
Equity securities	946			1,344			3,788			3,207
Other investments	8,324			3,120			14,600			10,016
Life settlements and other	—			1,443			6,509			11,026
Investment income from equities and other investments	9,270			5,907			24,897			24,249
Gross investment income	71,857			54,649			210,060			158,458
Investment expenses	(2,427		)	(2,621		)	(7,842		)	(8,274		)
Net investment income	$	69,430		$	52,028		$	202,218		$	150,184

Realized Gain (Loss) on Investments

Components of net realized and unrealized gains and losses for the three and nine months ended September 30, 2018 and 2017 were as follows:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Net realized gains (losses) on sale:
Gross realized gains on fixed maturity securities, available-for-sale	$	—		$	8		$	27		$	345
Gross realized losses on fixed maturity securities, available-for-sale	(2		)	(5		)	(80		)	(91		)
Net realized gains (losses) on fixed maturity securities, trading	(8,797		)	4,595			(19,310		)	3,608
Net realized gains on equity securities, trading	666			340			3,569			1,150
Net realized gains (losses) on funds held - directly managed	(1,904		)	422			(2,849		)	(3,720		)
Total net realized gains (losses) on sale	$	(10,037	)	$	5,360		$	(18,643	)	$	1,292
Net unrealized gains (losses):
Fixed maturity securities, trading	$	(13,423	)	$	(10,747	)	$	(159,691	)	$	23,795
Equity securities, trading	1,830			2,652			6,152			13,209
Other Investments	(35,188		)	27,802			(37,059		)	71,007
Change in fair value of embedded derivative on funds held – directly managed	(182		)	3,967			(41,107		)	28,807
Change in value of fair value option on funds held - directly managed	(223		)	267			(4,323		)	1,587
Total net unrealized gains (losses)	(47,186		)	23,941			(236,028		)	138,405
Net realized and unrealized gains (losses)	$	(57,223	)	$	29,301		$	(254,671	)	$	139,697

Unrealized Gain (Loss) on Investments

Components of net realized and unrealized gains and losses for the three and nine months ended September 30, 2018 and 2017 were as follows:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Net realized gains (losses) on sale:
Gross realized gains on fixed maturity securities, available-for-sale	$	—		$	8		$	27		$	345
Gross realized losses on fixed maturity securities, available-for-sale	(2		)	(5		)	(80		)	(91		)
Net realized gains (losses) on fixed maturity securities, trading	(8,797		)	4,595			(19,310		)	3,608
Net realized gains on equity securities, trading	666			340			3,569			1,150
Net realized gains (losses) on funds held - directly managed	(1,904		)	422			(2,849		)	(3,720		)
Total net realized gains (losses) on sale	$	(10,037	)	$	5,360		$	(18,643	)	$	1,292
Net unrealized gains (losses):
Fixed maturity securities, trading	$	(13,423	)	$	(10,747	)	$	(159,691	)	$	23,795
Equity securities, trading	1,830			2,652			6,152			13,209
Other Investments	(35,188		)	27,802			(37,059		)	71,007
Change in fair value of embedded derivative on funds held – directly managed	(182		)	3,967			(41,107		)	28,807
Change in value of fair value option on funds held - directly managed	(223		)	267			(4,323		)	1,587
Total net unrealized gains (losses)	(47,186		)	23,941			(236,028		)	138,405
Net realized and unrealized gains (losses)	$	(57,223	)	$	29,301		$	(254,671	)	$	139,697

Schedule of Restricted Assets

The carrying value of our restricted assets, including restricted cash of $474.6 million and $257.7 million, as at September 30, 2018 and December 31, 2017, respectively, was as follows:



	September 30, 2018		December 31, 2017
Collateral in trust for third party agreements	$	3,354,994	$	3,118,892
Assets on deposit with regulatory authorities	563,139		599,829
Collateral for secured letter of credit facilities	134,286		151,467
Funds at Lloyd's ⁽¹⁾	422,657		234,833
	$	4,475,076	$	4,105,021

Funds Held - Directly Managed (Tables)

9 Months Ended

Sep. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Carrying Value of Assets and Liabilities Underlying Funds Held - Directly Managed

The following table presents the fair values of assets and liabilities underlying the funds held - directly managed account as at September 30, 2018 and December 31, 2017:



	September 30, 2018		December 31, 2017
Fixed maturity investments:
U.S. government and agency	$	98,928	$	69,850
Non-U.S. government	22,610		2,926
Corporate	641,460		695,490
Municipal	53,679		58,930
Residential mortgage-backed	70,196		29,439
Commercial mortgage-backed	220,077		211,186
Asset-backed	95,743		97,565
Total fixed maturity investments	$	1,202,693	$	1,165,386
Other assets	14,489		14,554
	$	1,217,182	$	1,179,940

Contractual Maturities of Fixed Maturity Investments Underlying Funds Held - Directly Managed



As at September 30, 2018	Amortized Cost		Fair Value		% of Total Fair Value
One year or less	$	33,247	$	33,105	2.8	%
More than one year through two years	69,423		68,667		5.7	%
More than two years through five years	206,922		202,077		16.8	%
More than five years through ten years	287,706		277,396		23.1	%
More than ten years	246,045		235,432		19.6	%
Residential mortgage-backed	71,876		70,196		5.8	%
Commercial mortgage-backed	231,443		220,077		18.3	%
Asset-backed	95,877		95,743		7.9	%
	$	1,242,539	$	1,202,693	100.0	%

Funds Held - Directly Managed, by Credit Rating

Credit Ratings

The following table sets forth the credit ratings of the fixed maturity investments underlying the funds held - directly managed account as at September 30, 2018:



	Amortized Cost		Fair Value		% of Total Investments		AAA Rated			AA Rated			A Rated			BBB Rated			Non- Investment Grade

U.S. government and agency	$	100,764	$	98,928	8.2	%	$	98,928		$	—		$	—		$	—		$	—
Non-U.S. government	22,537		22,610		1.9	%	—			3,827			12,088			6,695			—
Corporate	665,043		641,460		53.3	%	7,701			25,792			285,188			321,285			1,494
Municipal	54,999		53,679		4.5	%	—			16,555			29,960			7,164			—
Residential mortgage-backed	71,876		70,196		5.8	%	60,792			—			—			—			9,404
Commercial mortgage-backed	231,443		220,077		18.3	%	211,747			6,367			1,963			—			—
Asset-backed	95,877		95,743		8.0	%	75,417			16,289			4,037			—			—
Total	$	1,242,539	$	1,202,693	100.0	%	$	454,585		$	68,830		$	333,236		$	335,144		$	10,898
% of total fair value							37.8		%	5.7		%	27.7		%	27.9		%	0.9		%

Net Investment Income

Major categories of net investment income underlying the funds held - directly managed for the three and nine months ended September 30, 2018 and 2017 are summarized as follows:



	Three Months Ended						Nine Months Ended
	September 30						September 30
	2018			2017			2018			2017
Fixed maturity investments	$	10,014		$	8,702		$	28,649		$	25,004
Short-term investments and cash and cash equivalents	42			89			179			216
Gross investment income	10,056			8,791			28,828			25,220
Investment expenses	(280		)	(275		)	(838		)	(1,099		)
Investment income on funds held - directly managed	$	9,776		$	8,516		$	27,990		$	24,121

Net Realized and Unrealized Investment (Losses) Gains

Net realized gains (losses) and change in fair value for the three and nine months ended September 30, 2018 and 2017 are summarized as follows:



	Three Months Ended					Nine Months Ended
	September 30					September 30
	2018			2017		2018			2017
Net realized gains (losses) on fixed maturity securities	$	(1,904	)	$	422	$	(2,849	)	$	(3,720	)
Change in fair value of embedded derivative	(182		)	3,967		(41,107		)	28,807
Change in value of fair value option on funds held - directly managed	(223		)	267		(4,323		)	1,587
Net realized gains (losses) and change in fair value of funds held - directly managed	$	(2,309	)	$	4,656	$	(48,279	)	$	26,674

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Categorized Investments Recorded at Fair Value among Levels



	December 31, 2017
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value Based on NAV as Practical Expedient		Total Fair Value
Investments:
Fixed maturity investments:
U.S. government and agency	$	—	$	558,223	$	—	$	—	$	558,223
Non-U.S. government	—		692,569		—		—		692,569
Corporate	—		3,411,003		67,178		—		3,478,181
Municipal	—		105,357		—		—		105,357
Residential mortgage-backed	—		285,664		3,080		—		288,744
Commercial mortgage-backed	—		400,054		21,494		—		421,548
Asset-backed	—		514,055		27,892		—		541,947
	$	—	$	5,966,925	$	119,644	$	—	$	6,086,569
Equities:
Equities — U.S.	$	103,652	$	2,711	$	—	$	—	$	106,363
Equities — International	—		240		—		—		240
	$	103,652	$	2,951	$	—	$	—	$	106,603
Other investments:
Private equities and private equity funds	$	—	$	—	$	—	$	289,556	$	289,556
Fixed income funds	—		202,570		—		27,429		229,999
Hedge funds	—		—		—		63,773		63,773
Equity funds	—		121,046		—		128,429		249,475
CLO equities	—		—		56,765		—		56,765
CLO equity funds	—		—		—		12,840		12,840
Private credit funds	—		—		—		10,156		10,156
Other	—		—		314		514		828
	$	—	$	323,616	$	57,079	$	532,697	$	913,392
Total Investments	$	103,652	$	6,293,492	$	176,723	$	532,697	$	7,106,564
Funds Held - Directly Managed:
U.S. government and agency	$	—	$	69,850	$	—	$	—	$	69,850
Non-U.S. government	—		2,926		—		—		2,926
Corporate	—		695,490		—		—		695,490
Municipal	—		58,930		—		—		58,930
Residential mortgage-backed	—		29,439		—		—		29,439
Commercial mortgage-backed	—		211,186		—		—		211,186
Asset-backed	—		97,565		—		—		97,565
Other assets	—		14,554		—		—		14,554
	$	—	$	1,179,940	$	—	$	—	$	1,179,940

Reinsurance balances recoverable:	$	—	$	—	$	542,224	$	—	$	542,224

Other Assets:
Derivative Instruments	$	—	$	319	$	—	$	—	$	319
	$	—	$	319	$	—	$	—	$	319

Losses and LAE:	$	—	$	—	$	1,794,669	$	—	$	1,794,669

Other Liabilities:
Derivative Instruments	$	—	$	7,246	$	—	$	—	$	7,246
	$	—	$	7,246	$	—	$	—	$	7,246

We have categorized our investments that are recorded at fair value on a recurring basis among levels based on the observability of inputs, or at fair value using NAV per share (or its equivalent) as follows:



	September 30, 2018
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value Based on NAV as Practical Expedient		Total Fair Value
Investments:
Fixed maturity investments:
U.S. government and agency	$	—	$	493,778	$	—	$	—	$	493,778
Non-U.S. government	—		1,093,768		—		—		1,093,768
Corporate	—		3,763,158		23,379		—		3,786,537
Municipal	—		79,966		—		—		79,966
Residential mortgage-backed	—		273,705		1,795		—		275,500
Commercial mortgage-backed	—		402,192		9,383		—		411,575
Asset-backed	—		535,578		31,722		—		567,300
	$	—	$	6,642,145	$	66,279	$	—	$	6,708,424
Equities:
Equities — U.S.	$	70,720	$	29	$	2,016	$	—	$	72,765
Equities — International	53,541		2,296		1,712		—		57,549
	$	124,261	$	2,325	$	3,728	$	—	$	130,314
Other investments:
Private equities and private equity funds	$	—	$	—	$	—	$	256,618	$	256,618
Fixed income funds	—		327,375		—		55,953		383,328
Hedge funds	—		—		—		879,571		879,571
Equity funds	—		117,337		—		264,646		381,983
CLO equities	—		—		48,368		—		48,368
CLO equity fund	—		—		—		41,501		41,501
Private credit funds	—		—		—		39,751		39,751
Call options on equities	—		4,590		—		—		4,590
Other	—		—		313		407		720
	$	—	$	449,302	$	48,681	$	1,538,447	$	2,036,430
Total Investments	$	124,261	$	7,093,772	$	118,688	$	1,538,447	$	8,875,168
Funds Held - Directly Managed:
U.S. government and agency	$	—	$	98,928	$	—	$	—	$	98,928
Non-U.S. government	—		22,610		—		—		22,610
Corporate	—		641,460		—		—		641,460
Municipal	—		53,679		—		—		53,679
Residential mortgage-backed	—		70,196		—		—		70,196
Commercial mortgage-backed	—		220,077		—		—		220,077
Asset-backed	—		95,743		—		—		95,743
Other assets	—		14,489		—		—		14,489
	$	—	$	1,217,182	$	—	$	—	$	1,217,182

Reinsurance balances recoverable:	$	—	$	—	$	792,553	$	—	$	792,553

Other Assets:
Derivative Instruments	$	—	$	1,197	$	—	$	—	$	1,197
	$	—	$	1,197	$	—	$	—	$	1,197

Losses and LAE:	$	—	$	—	$	3,019,721	$	—	$	3,019,721

Other Liabilities:
Derivative Instruments	$	—	$	5,775	$	—	$	—	$	5,775
	$	—	$	5,775	$	—	$	—	$	5,775

Reconciliation for Assets Measured at Fair Value on a Recurring Basis



	Three Months Ended September 30, 2018
	Corporate			Residential mortgage-backed		Commercial mortgage-backed			Asset-backed			Equities		Other Investments			Total
Beginning fair value	$	27,823		$	—	$	15,326		$	46,608		$	2,016	$	54,154		$	145,927
Purchases	205			—		1,599			16,376			—		—			18,180
Sales	(3,731		)	—		(3,271		)	(28,182		)	—		—			(35,184		)
Total realized and unrealized gains (losses)	92			1		(726		)	(346		)	—		(5,473		)	(6,452		)
Transfer into Level 3 from Level 2	292			1,794		—			(1		)	1,712		—			3,797
Transfer out of Level 3 into Level 2	(1,302		)	—		(3,545		)	(2,733		)	—		—			(7,580		)
Ending fair value	$	23,379		$	1,795	$	9,383		$	31,722		$	3,728	$	48,681		$	118,688



	Three Months Ended September 30, 2017
	Corporate			Residential mortgage-backed			Commercial mortgage-backed			Asset-backed			Equities		Other Investments			Total
Beginning fair value	$	54,356		$	693		$	22,865		$	40,433		$	—	$	57,119		$	175,466
Purchases	2,510			—			11,274			4,350			—		143			18,277
Sales	(3,350		)	(33		)	(602		)	(1,184		)	—		—			(5,169		)
Total realized and unrealized gains (losses)	(834		)	3			(398		)	(384		)	—		(1,538		)	(3,151		)
Transfer into Level 3 from Level 2	5,670			—			616			4,002			—		—			10,288
Transfer out of Level 3 into Level 2	(5,193		)	(663		)	(1,619		)	(10,528		)	—		—			(18,003		)
Ending fair value	$	53,159		$	—		$	32,136		$	36,689		$	—	$	55,724		$	177,708



	Nine Months Ended September 30, 2018
	Corporate			Residential mortgage-backed			Commercial mortgage-backed			Asset-backed			Equities		Other Investments			Total
Beginning fair value	$	67,178		$	3,080		$	21,494		$	27,892		$	—	$	57,079		$	176,723
Purchases	12,008			—			3,402			45,967			2,000		752			64,129
Sales	(64,641		)	(1,184		)	(4,998		)	(31,994		)	—		(600		)	(103,417		)
Total realized and unrealized gains (losses)	29			(32		)	(674		)	(417		)	16		(8,550		)	(9,628		)
Transfer into Level 3 from Level 2	15,551			1,794			4,897			2,078			1,712		—			26,032
Transfer out of Level 3 into Level 2	(6,746		)	(1,863		)	(14,738		)	(11,804		)	—		—			(35,151		)
Ending fair value	$	23,379		$	1,795		$	9,383		$	31,722		$	3,728	$	48,681		$	118,688



	Nine Months Ended September 30, 2017
	Corporate			Residential mortgage-backed			Commercial mortgage-backed			Asset-backed			Equities		Other Investments			Total
Beginning fair value	$	74,534		$	—		$	12,213		$	14,692		$	—	$	76,878		$	178,317
Purchases	18,078			711			21,621			5,730			—		435			46,575
Sales	(28,467		)	(38		)	(1,336		)	(8,545		)	—		—			(38,386		)
Total realized and unrealized losses	(184		)	(10		)	(67		)	(175		)	—		(9,239		)	(9,675		)
Transfer into Level 3 from Level 2	10,615			—			18,532			53,338			—		—			82,485
Transfer out of Level 3 into Level 2	(21,417		)	(663		)	(18,827		)	(28,351		)	—		(12,350		)	(81,608		)
Ending fair value	$	53,159		$	—		$	32,136		$	36,689		$	—	$	55,724		$	177,708

Reconciliation for Liabilities Measured at Fair Value on a Recurring Basis



	Three Months Ended
	September 30, 2018						September 30, 2017
	Liability for losses and LAE			Reinsurance balances recoverable			Liability for losses and LAE			Reinsurance balances recoverable
Beginning fair value	$	3,221,366		$	837,373		$	1,892,297		$	554,759
Assumed business	—			—			—			—
Changes in nominal amounts:
Net incurred losses and LAE	(19,973		)	1,085			(22,711		)	(3,181		)
Paid losses	(149,132		)	(41,819		)	(36,466		)	(9,453		)
Changes in fair value:
Discounted cash flows	(2,811		)	483			(6,826		)	730
Risk margin	(7,762		)	(1,949		)	(3,845		)	(897		)
Effect of exchange rate movements	(21,967		)	(2,620		)	32,803			3,790
Ending fair value	$	3,019,721		$	792,553		$	1,855,252		$	545,748



	Nine Months Ended
	September 30, 2018						September 30, 2017
	Liability for losses and LAE			Reinsurance balances recoverable			Liability for losses and LAE			Reinsurance balances recoverable
Beginning fair value	$	1,794,669		$	542,224		$	—		$	—
Assumed business	1,890,061			372,780			1,966,843			565,824
Changes in nominal amounts:
Net incurred losses and LAE	(75,169		)	3,469			(55,356		)	(5,276		)
Paid losses	(453,180		)	(95,354		)	(136,519		)	(30,947		)
Changes in fair value:
Discounted cash flows	(23,674		)	(13,399		)	10,187			9,143
Risk margin	(26,508		)	(4,668		)	(12,897		)	(2,599		)
Effect of exchange rate movements	(86,478		)	(12,499		)	82,994			9,603
Ending fair value	$	3,019,721		$	792,553		$	1,855,252		$	545,748

Quantitative Information



		September 30, 2018	December 31, 2017
Valuation Technique	Unobservable (U) and Observable (O) Inputs	Weighted Average
Internal model	Corporate bond yield (O)	A rated	A rated
Internal model	Credit spread for non-performance risk (U)	0.2%	0.2%
Internal model	Risk cost of capital (U)	5.0%	5.0%
Internal model	Weighted average cost of capital (U)	8.5%	8.5%
Internal model	Duration - liability (U)	8.05 years	11.41 years
Internal model	Duration - reinsurance balances recoverable (U)	9.03 years	11.66 years

Derivative and Hedging Instruments (Tables)

9 Months Ended

Sep. 30, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Estimated Fair Value and Unrealized Gains (Losses) on Derivative Instruments

The following table presents the amounts of the net gains and losses deferred in the CTA account in AOCI relating to these qualifying Euro-loan non-derivative hedging instruments for the three and nine months ended September 30, 2018 and 2017.



	Amount of Gains (Losses) Deferred in AOCI
	Three Months Ended					Nine Months Ended
	September 30,					September 30,
	2018		2017			2018		2017
Net gains (losses) on qualifying non-derivative hedges	$	696	$	(1,785	)	$	3,144	$	(8,280	)



	September 30, 2018						December 31, 2017
			Fair Value						Fair Value
	Gross Notional Amount		Assets		Liabilities		Gross Notional Amount		Assets		Liabilities
Foreign exchange forward - AUD	$	43,410	$	237	$	—	$	32,810	$	—	$	965
Foreign exchange forward - EUR	69,800		175		—		—		—		—
Foreign exchange forward - CAD	—		—		—		27,141		11		512
Total qualifying hedges	$	113,210	$	412	$	—	$	59,951	$	11	$	1,477



	Amount of Gains (Losses) Deferred in AOCI
	Three Months Ended					Nine Months Ended
	September 30,					September 30,
	2018		2017			2018		2017
Foreign exchange forward - AUD	$	678	$	(1,243	)	$	2,286	$	(1,805	)
Foreign exchange forward - EUR	52		—			52		—
Foreign exchange forward - CAD	—		(1,038		)	—		(1,154		)
Net gains (losses) on qualifying derivative hedges	$	730	$	(2,281	)	$	2,338	$	(2,959	)



	September 30, 2018						December 31, 2017
			Fair Value						Fair Value
	Gross Notional Amount		Assets		Liabilities		Gross Notional Amount		Assets		Liabilities
Foreign exchange forward - AUD	$	35,090	$	236	$	—	$	57,028	$	—	$	1,002
Foreign exchange forward - CAD	91,577		42		—		—		—		—
Foreign exchange forward - EUR	29,035		71		500		19,235		46		455
Foreign exchange forward - GBP	251,059		436		5,275		207,323		262		4,312
Total non-qualifying hedges	$	406,761	$	785	$	5,775	$	283,586	$	308	$	5,769



	Gains (Losses) on non-qualifying-hedges included in net earnings
	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018		2017
Foreign exchange forward - AUD	$	957		$	—		$	3,453	$	—
Foreign exchange forward - CAD	(1,782		)	—			5,465		—
Foreign exchange forward - EUR	458			—			1,815		(562		)
Foreign exchange forward - GBP	4,154			(3,831		)	8,389		$	(4,701	)
Net gains (losses) on non-qualifying hedges	$	3,787		$	(3,831	)	$	19,122	$	(5,263	)

- Definition

Tabular disclosure of pertinent information about a derivative or group of derivatives on a disaggregated basis, such as for individual instruments, or small groups of similar instruments. May include a combination of the type of instrument, risks being hedged, notional amount, hedge designation, related hedged item, inception date, maturity date, or other relevant item.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109980867&loc=d3e41620-113959

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
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Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
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-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109980867&loc=d3e41641-113959

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(n)(2))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579240-113959

+ Details

Reinsurance Balances Recoverable (Tables)

9 Months Ended

Sep. 30, 2018

Insurance [Abstract]

Summary of Reinsurance Reserves Recoverable and Uncollectible Reinsurance Balances Recoverable

The following tables provide the total reinsurance balances recoverable as at September 30, 2018 and December 31, 2017:



	September 30, 2018
	Non-life Run-off			Atrium			StarStone			Total
Recoverable from reinsurers on unpaid:
Outstanding losses	$	932,142		$	13,051		$	214,963		$	1,160,156
IBNR	664,873			31,445			175,302			871,620
Fair value adjustments	(14,489		)	886			(1,550		)	(15,153		)
Fair value adjustments - fair value option	(170,436		)	—			—			(170,436		)
Total reinsurance reserves recoverable	1,412,090			45,382			388,715			1,846,187
Paid losses recoverable	108,218			(1,808		)	22,959			129,369
	$	1,520,308		$	43,574		$	411,674		$	1,975,556
Reconciliation to Consolidated Balance Sheet:
Reinsurance balances recoverable	$	727,755		$	43,574		$	411,674		$	1,183,003
Reinsurance balances recoverable - fair value option	792,553			—			—			792,553
Total	$	1,520,308		$	43,574		$	411,674		$	1,975,556



	December 31, 2017
	Non-life Run-off			Atrium			StarStone			Other		Total
Recoverable from reinsurers on unpaid:
Outstanding losses	$	932,284		$	7,472		$	211,650		$	16	$	1,151,422
IBNR	590,154			31,476			242,620			—		864,250
Fair value adjustments	(12,970		)	1,583			(2,253		)	—		(13,640		)
Fair value adjustments - fair value option	(131,983		)	—			—			—		(131,983		)
Total reinsurance reserves recoverable	1,377,485			40,531			452,017			16		1,870,049
Paid losses recoverable	128,253			(451		)	23,179			—		150,981
	$	1,505,738		$	40,080		$	475,196		$	16	$	2,021,030
Reconciliation to Consolidated Balance Sheet:
Reinsurance balances recoverable	$	963,514		$	40,080		$	475,196		$	16	$	1,478,806
Reinsurance balances recoverable - fair value option	542,224			—			—			—		542,224
Total	$	1,505,738		$	40,080		$	475,196		$	16	$	2,021,030



	September 30, 2018								December 31, 2017
	Gross		Provisions for Bad Debt		Net		Provisions as a % of Gross		Gross		Provisions for Bad Debt		Net		Provisions as a % of Gross
Reinsurers rated A- or above	$	1,600,220	$	54,960	$	1,545,260	3.4	%	$	1,252,887	$	51,115	$	1,201,772	4.1	%
Reinsurers rated below A-, secured	397,775		—		397,775		—	%	771,097		—		771,097		—	%
Reinsurers rated below A-, unsecured	135,987		103,466		32,521		76.1	%	162,259		114,098		48,161		70.3	%
Total	$	2,133,982	$	158,426	$	1,975,556	7.4	%	$	2,186,243	$	165,213	$	2,021,030	7.6	%



	Three Months Ended September 30,												Nine Months Ended September 30,
	2018						2017						2018						2017
	Premiums Written			Premiums Earned			Premiums Written			Premiums Earned			Premiums Written			Premiums Earned			Premiums Written			Premiums Earned
Non-life Run-off
Gross	$	9,912		$	17,746		$	11,751		$	9,345		$	16,354		$	54,044		$	13,956		$	15,353
Ceded	(5,134		)	(7,304		)	(284		)	(2,930		)	(13,137		)	(26,815		)	(503		)	(5,497		)
Net	$	4,778		$	10,442		$	11,467		$	6,415		$	3,217		$	27,229		$	13,453		$	9,856
Atrium
Gross	$	39,995		$	42,505		$	36,377		$	39,591		$	130,997		$	121,974		$	117,355		$	111,633
Ceded	(2,854		)	(5,528		)	(10,388		)	(6,818		)	(17,779		)	(15,252		)	(18,120		)	(14,260		)
Net	$	37,141		$	36,977		$	25,989		$	32,773		$	113,218		$	106,722		$	99,235		$	97,373
StarStone
Gross	$	282,525		$	281,467		$	200,007		$	217,833		$	888,867		$	761,694		$	651,107		$	636,137
Ceded	(62,799		)	(65,112		)	(102,958		)	(110,183		)	(269,339		)	(234,892		)	(319,658		)	(294,528		)
Net	$	219,726		$	216,355		$	97,049		$	107,650		$	619,528		$	526,802		$	331,449		$	341,609
Other
Gross	$	846		$	848		$	2,424		$	1,444		$	2,858		$	2,878		$	4,506		$	4,658
Ceded	(24		)	(25		)	(753		)	(257		)	13			(3		)	(860		)	(1,002		)
Net	$	822		$	823		$	1,671		$	1,187		$	2,871		$	2,875		$	3,646		$	3,656
Total
Gross	$	333,278		$	342,566		$	250,559		$	268,213		$	1,039,076		$	940,590		$	786,924		$	767,781
Ceded	(70,811		)	(77,969		)	(114,383		)	(120,188		)	(300,242		)	(276,962		)	(339,141		)	(315,287		)
Total	$	262,467		$	264,597		$	136,176		$	148,025		$	738,834		$	663,628		$	447,783		$	452,494

Reinsurance Balances Recoverable by Reinsurer



	September 30, 2018
	Non-life Run-off		Atrium		StarStone		Total		% of Total
Top ten reinsurers	$	1,167,500	$	28,669	$	239,686	$	1,435,855	72.7	%
Other reinsurers > $1 million	335,939		14,232		168,194		518,365		26.2	%
Other reinsurers < $1 million	16,869		673		3,794		21,336		1.1	%
Total	$	1,520,308	$	43,574	$	411,674	$	1,975,556	100.0	%



	December 31, 2017
	Non-life Run-off		Atrium		StarStone		Other		Total		% of Total
Top ten reinsurers	$	1,166,057	$	22,422	$	328,257	$	—	$	1,516,736	75.0	%
Other reinsurers > $1 million	322,722		16,631		144,336		—		483,689		24.0	%
Other reinsurers < $1 million	16,959		1,027		2,603		16		20,605		1.0	%
Total	$	1,505,738	$	40,080	$	475,196	$	16	$	2,021,030	100.0	%



	September 30, 2018		December 31, 2017
Information regarding top ten reinsurers:
Number of top 10 reinsurers rated A- or better	7		6
Number of top 10 non-rated reinsurers ⁽¹⁾	3		4

Top 10 rated A- or better reinsurers recoverables	$	1,116,423	$	829,164
Top 10 collaterized non-rated reinsurers recoverables ⁽¹⁾	$	319,432	$	687,572
	$	1,435,855	$	1,516,736

Single reinsurers that represent 10% or more of total reinsurance balance recoverables as at September 30, 2018:

Hannover Ruck SE ⁽²⁾	$	327,287	$	320,047
Lloyd's Syndicates ⁽³⁾	$	303,598	$	193,838

⁽²⁾ Hannover Ruck SE is rated AA- by Standard & Poor’s and A+ by A.M. Best.

⁽³⁾ Lloyd's Syndicates are rated A+ by Standard & Poor's and A by A.M. Best.

Losses and Loss Adjustment Expenses (Tables)

9 Months Ended

Sep. 30, 2018

Insurance [Abstract]

Total Losses and Loss Adjustment Expense Liabilities, and Reconciliation of Beginning and Ending Balances

The following table summarizes the liability for losses and LAE by segment as at September 30, 2018 and December 31, 2017:



	September 30, 2018
	Non-life Run-off			Atrium		StarStone			Total
Outstanding losses	$	3,998,430		$	83,138	$	714,231		$	4,795,799
IBNR	3,072,291			152,462		723,987			3,948,740
Fair value adjustments	(120,916		)	4,749		(381		)	(116,548		)
Fair value adjustments - fair value option	(457,215		)	—		—			(457,215		)
ULAE	340,165			2,418		22,374			364,957
Total	$	6,832,755		$	242,767	$	1,460,211		$	8,535,733

Reconciliation to Consolidated Balance Sheet:
Loss and loss adjustment expenses	$	3,813,034		$	242,767	$	1,460,211		$	5,516,012
Loss and loss adjustment expenses, at fair value	3,019,721			—		—			3,019,721
Total	$	6,832,755		$	242,767	$	1,460,211		$	8,535,733



	December 31, 2017
	Non-life Run-off			Atrium		StarStone			Total
Outstanding losses	$	3,185,703		$	78,363	$	590,977		$	3,855,043
IBNR	2,903,927			150,508		599,221			3,653,656
Fair value adjustments	(125,998		)	9,547		(555		)	(117,006		)
Fair value adjustments - fair value option	(314,748		)	—		—			(314,748		)
ULAE	300,588			2,455		18,100			321,143
Total	$	5,949,472		$	240,873	$	1,207,743		$	7,398,088

Reconciliation to Consolidated Balance Sheet:
Loss and loss adjustment expenses	$	4,154,803		$	240,873	$	1,207,743		$	5,603,419
Loss and loss adjustment expenses, at fair value	$	1,794,669		$	—	$	—		$	1,794,669
Total	$	5,949,472		$	240,873	$	1,207,743		$	7,398,088

The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended					Nine Months Ended
	September 30,					September 30,
	2018			2017		2018			2017
Balance as at beginning of period	$	8,608,387		$	7,641,384	$	7,398,088		$	5,987,867
Less: reinsurance reserves recoverable	1,866,969			1,923,962		1,870,033			1,388,193
Less: deferred charges on retroactive reinsurance	71,393			88,475		80,192			94,551
Net balance as at beginning of period	6,670,025			5,628,947		5,447,863			4,505,123
Net incurred losses and LAE:
Current period	219,050			147,846		468,064			314,791
Prior periods	(65,076		)	(72,134)		(201,737		)	(151,567		)
Total net incurred losses and LAE	153,974			75,712		266,327			163,224
Net paid losses:
Current period	(24,266		)	(15,928)		(62,843		)	(40,820		)
Prior periods	(296,709		)	(215,173)		(937,846		)	(670,117		)
Total net paid losses	(320,975		)	(231,101)		(1,000,689		)	(710,937		)
Effect of exchange rate movement	(26,825		)	55,712		(108,659		)	139,448
Acquired on purchase of subsidiaries	22,713			3,282		366,519			3,282
Assumed business	103,615			—		1,631,166			1,432,412
Net balance as at September 30	6,602,527			5,532,552		6,602,527			5,532,552
Plus: reinsurance reserves recoverable	1,846,187			1,998,001		1,846,187			1,998,001
Plus: deferred charges on retroactive reinsurance	87,019			85,164		87,019			85,164
Balance as at September 30	$	8,535,733		$	7,615,717	$	8,535,733		$	7,615,717

The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the three and nine months ended September 30, 2018 and 2017 for the Non-life Run-off segment:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Balance as at beginning of period	$	7,025,750		$	6,317,279		$	5,949,472		$	4,716,363
Less: reinsurance reserves recoverable	1,462,139			1,500,557			1,377,485			1,000,953
Less: deferred charges on retroactive insurance	71,393			88,475			80,192			94,551
Net balance as at beginning of period	5,492,218			4,728,247			4,491,795			3,620,859
Net incurred losses and LAE:
Current period	10,017			30			15,476			1,205
Prior periods	(72,795)			(70,912		)	(221,366		)	(139,246		)
Total net incurred losses and LAE	(62,778)			(70,882		)	(205,890		)	(138,041		)
Net paid losses:
Current period	(2,713)			(33		)	(3,304		)	(404		)
Prior periods	(193,057)			(135,981		)	(641,361		)	(436,594		)
Total net paid losses	(195,770)			(136,014		)	(644,665		)	(436,998		)
Effect of exchange rate movement	(26,352		)	46,080			(102,030)			120,592
Acquired on purchase of subsidiaries	22,713			3,282			173,538			3,282
Assumed business	103,615			—			1,620,898			1,401,019
Net balance as at September 30	5,333,646			4,570,713			5,333,646			4,570,713
Plus: reinsurance reserves recoverable	1,412,090			1,475,855			1,412,090			1,475,855
Plus: deferred charges on retroactive reinsurance	87,019			85,164			87,019			85,164
Balance as at September 30	$	6,832,755		$	6,131,732		$	6,832,755		$	6,131,732

The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the three and nine months ended September 30, 2018 and 2017 for the Atrium segment:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Balance as at beginning of period	$	234,232		$	208,646		$	240,873		$	212,122
Less: reinsurance reserves recoverable	38,253			29,749			40,531			30,009
Net balance as at beginning of period	195,979			178,897			200,342			182,113
Net incurred losses and LAE:
Current period	20,033			37,284			56,514			66,563
Prior periods	(2,180		)	(2,011		)	(4,563		)	(10,613		)
Total net incurred losses and LAE	17,853			35,273			51,951			55,950
Net paid losses:
Current period	(8,080		)	(5,139		)	(25,699		)	(14,799		)
Prior periods	(8,230		)	(8,992		)	(27,488		)	(25,826		)
Total net paid losses	(16,310		)	(14,131		)	(53,187		)	(40,625		)
Effect of exchange rate movement	(137		)	1,474			(1,721		)	4,075
Net balance as at September 30	197,385			201,513			197,385			201,513
Plus: reinsurance reserves recoverable	45,382			44,207			45,382			44,207
Balance as at September 30	$	242,767		$	245,720		$	242,767		$	245,720

The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the three and nine months ended September 30, 2018 and 2017 for our StarStone segment:



	Three Months Ended					Nine Months Ended
	September 30,					September 30,
	2018		2017			2018			2017
Balance as at beginning of period	$	1,348,405	$	1,115,459		$	1,207,743		$	1,059,382
Less: reinsurance reserves recoverable	366,577		393,656			452,017			357,231
Net balance as at beginning of period	981,828		721,803			755,726			702,151
Net incurred losses and LAE:
Current period	189,000		110,532			396,074			247,023
Prior periods	9,899		789			24,192			(1,708		)
Total net incurred losses and LAE	198,899		111,321			420,266			245,315
Net paid losses:
Current period	(13,473)		(10,756		)	(33,840		)	(25,617		)
Prior periods	(95,422)		(70,200		)	(268,997		)	(207,697		)
Total net paid losses	(108,895)		(80,956		)	(302,837		)	(233,314		)
Effect of exchange rate movement	(336)		8,158			(4,908		)	14,781
Acquired on purchase of subsidiaries	—		—			192,981			—
Assumed business	—		—			10,268			31,393
Net balance as at September 30	1,071,496		760,326			1,071,496			760,326
Plus: reinsurance reserves recoverable	388,715		477,939			388,715			477,939
Balance as at September 30	$	1,460,211	$	1,238,265		$	1,460,211		$	1,238,265

Schedule of Incurred Losses

The tables below provide the net incurred losses and LAE by segment for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended												Three Months Ended
	September 30, 2018												September 30, 2017
	Non-life Run-off			Atrium			StarStone			Total			Non-life Run-off			Atrium			StarStone			Total
Net losses paid	$	195,770		$	16,310		$	108,895		$	320,975		$	136,014		$	14,131		$	80,956		$	231,101
Net change in case and LAE reserves	(128,662		)	(546		)	17,549			(111,659		)	(66,392		)	239			(934		)	(67,087		)
Net change in IBNR reserves	(102,148		)	2,818			71,160			(28,170		)	(120,766		)	22,525			30,173			(68,068		)
Increase (reduction) in estimates of net ultimate losses	(35,040		)	18,582			197,604			181,146			(51,144		)	36,895			110,195			95,946
Increase in provisions for bad debt	—			—			—			—			—			242			—			242
Increase (reduction) in provisions for unallocated LAE	(24,460		)	(2		)	1,582			(22,880		)	(16,038		)	64			1,247			(14,727		)
Amortization of deferred charges	1,582			—			—			1,582			3,311			—			—			3,311
Amortization of fair value adjustments	4,247			(727		)	(287		)	3,233			3,493			(1,928		)	(121		)	1,444
Changes in fair value - fair value option	(9,107		)	—			—			(9,107		)	(10,504		)	—			—			(10,504		)
Net incurred losses and LAE	$	(62,778	)	$	17,853		$	198,899		$	153,974		$	(70,882	)	$	35,273		$	111,321		$	75,712



	Nine Months Ended												Nine Months Ended
	September 30, 2018												September 30, 2017
	Non-life Run-off			Atrium			StarStone			Total			Non-life Run-off			Atrium			StarStone			Total
Net losses paid	$	644,665		$	53,187		$	302,837		$	1,000,689		$	436,998		$	40,625		$	233,314		$	710,937
Net change in case and LAE reserves	(376,512		)	(98		)	38,915			(337,695		)	(276,935		)	(288		)	(2,148		)	(279,371		)
Net change in IBNR reserves	(413,898		)	2,964			75,031			(335,903		)	(261,724		)	17,179			13,371			(231,174		)
Increase (reduction) in estimates of net ultimate losses	(145,745		)	56,053			416,783			327,091			(101,661		)	57,516			244,537			200,392
Increase (reduction) in provisions for bad debt	—			—			—			—			(735		)	242			—			(493		)
Increase (reduction) in provisions for unallocated LAE	(48,723		)	—			4,012			(44,711		)	(41,296		)	—			1,533			(39,763		)
Amortization of deferred charges	10,381			—			—			10,381			9,387			—			—			9,387
Amortization of fair value adjustments	10,312			(4,102		)	(529		)	5,681			5,518			(1,808		)	(755		)	2,955
Changes in fair value - fair value option	(32,115		)	—			—			(32,115		)	(9,254		)	—			—			(9,254		)
Net incurred losses and LAE	$	(205,890	)	$	51,951		$	420,266		$	266,327		$	(138,041	)	$	55,950		$	245,315		$	163,224

Net incurred losses and LAE in the Non-life Run-off segment for the three months ended September 30, 2018 and 2017 were as follows:



	Three Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period			Total
Net losses paid	$	193,057		$	2,713	$	195,770		$	135,981		$	33		$	136,014
Net change in case and LAE reserves	(128,827		)	165		(128,662		)	(66,376		)	(16		)	(66,392		)
Net change in IBNR reserves	(109,287		)	7,139		(102,148		)	(120,614		)	(152		)	(120,766		)
Increase (reduction) in estimates of net ultimate losses	(45,057		)	10,017		(35,040		)	(51,009		)	(135		)	(51,144		)
Increase (reduction) in provisions for unallocated LAE	(24,460		)	—		(24,460		)	(16,203		)	165			(16,038		)
Amortization of deferred charges	1,582			—		1,582			3,311			—			3,311
Amortization of fair value adjustments	4,247			—		4,247			3,493			—			3,493
Changes in fair value - fair value option	(9,107		)	—		(9,107		)	(10,504		)	—			(10,504		)
Net incurred losses and LAE	$	(72,795	)	$	10,017	$	(62,778	)	$	(70,912	)	$	30		$	(70,882	)

Net incurred losses and LAE in the Non-life Run-off segment for the nine months ended September 30, 2018 and 2017 were as follows:



	Nine Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period			Total
Net losses paid	$	641,361		$	3,304	$	644,665		$	436,594		$	404		$	436,998
Net change in case and LAE reserves	(377,735		)	1,223		(376,512		)	(276,903		)	(32		)	(276,935		)
Net change in IBNR reserves	(424,847		)	10,949		(413,898		)	(262,296		)	572			(261,724		)
Increase (reduction) in estimates of net ultimate losses	(161,221		)	15,476		(145,745		)	(102,605		)	944			(101,661		)
Reduction in provisions for bad debt	—			—		—			(735		)	—			(735		)
Increase (reduction) in provisions for unallocated LAE	(48,723		)	—		(48,723		)	(41,557		)	261			(41,296		)
Amortization of deferred charges	10,381			—		10,381			9,387			—			9,387
Amortization of fair value adjustments	10,312			—		10,312			5,518			—			5,518
Changes in fair value - fair value option	(32,115		)	—		(32,115		)	(9,254		)	—			(9,254		)
Net incurred losses and LAE	$	(221,366	)	$	15,476	$	(205,890	)	$	(139,246	)	$	1,205		$	(138,041	)

Net incurred losses and LAE in the Atrium segment for the three and nine months ended September 30, 2018 and 2017 were as follows:



	Three Months Ended September 30,
	2018					2017
	Prior Period		Current Period	Total		Prior Period		Current Period		Total
Net losses paid	8,230		8,080	16,310		8,992		5,139		14,131
Net change in case and LAE reserves	(4,142	)	3,596	(546	)	(2,781	)	3,020		239
Net change in IBNR reserves	(5,539	)	8,357	2,818		(6,273	)	28,798		22,525
Increase (reduction) in estimates of net ultimate losses	(1,451	)	20,033	18,582		(62	)	36,957		36,895
Increase (reduction) in provisions for bad debt	—		—	—		(96	)	338		242
Increase (reduction) in provisions for unallocated LAE	(2	)	—	(2	)	75		(11	)	64
Amortization of fair value adjustments	(727	)	—	(727	)	(1,928	)	—		(1,928	)
Net incurred losses and LAE	(2,180	)	20,033	17,853		(2,011	)	37,284		35,273



	Nine Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period		Total
Net losses paid	$	27,488		$	25,699	$	53,187		$	25,826		$	14,799	$	40,625
Net change in case and LAE reserves	(9,695		)	9,597		(98		)	(7,904		)	7,616		(288		)
Net change in IBNR reserves	(18,254		)	21,218		2,964			(26,631		)	43,810		17,179
Increase (reduction) in estimates of net ultimate losses	(461		)	56,514		56,053			(8,709		)	66,225		57,516
Increase (reduction) in provisions for bad debt	—			—		—			(96		)	338		242
Amortization of fair value adjustments	(4,102		)	—		(4,102		)	(1,808		)	—		(1,808		)
Net incurred losses and LAE	$	(4,563	)	$	56,514	$	51,951		$	(10,613	)	$	66,563	$	55,950

Net incurred losses and LAE in the StarStone segment for the three and nine months ended September 30, 2018 and 2017 were as follows:



	Three Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period		Total
Net losses paid	$	95,422		$	13,473	$	108,895		$	70,200		$	10,756	$	80,956
Net change in case and LAE reserves	(19,919		)	37,468		17,549			(14,037		)	13,103		(934		)
Net change in IBNR reserves	(63,294		)	134,454		71,160			(54,400		)	84,573		30,173
Increase in estimates of net ultimate losses	12,209			185,395		197,604			1,763			108,432		110,195
Increase (reduction) in provisions for unallocated LAE	(2,023		)	3,605		1,582			(853		)	2,100		1,247
Amortization of fair value adjustments	(287		)	—		(287		)	(121		)	—		(121		)
Net incurred losses and LAE	$	9,899		$	189,000	$	198,899		$	789		$	110,532	$	111,321



	Nine Months Ended September 30,
	2018								2017
	Prior Period			Current Period		Total			Prior Period			Current Period		Total
Net losses paid	$	268,997		$	33,840	$	302,837		$	207,697		$	25,617	$	233,314
Net change in case and LAE reserves	(55,541		)	94,456		38,915			(55,501		)	53,353		(2,148		)
Net change in IBNR reserves	(183,422		)	258,453		75,031			(149,165		)	162,536		13,371
Increase in estimates of net ultimate losses	30,034			386,749		416,783			3,031			241,506		244,537
Increase (reduction) in provisions for unallocated LAE	(5,313		)	9,325		4,012			(3,984		)	5,517		1,533
Amortization of fair value adjustments	(529		)	—		(529		)	(755		)	—		(755		)
Net incurred losses and LAE	$	24,192		$	396,074	$	420,266		$	(1,708	)	$	247,023	$	245,315

Premiums Written and Earned (Tables)

9 Months Ended

Sep. 30, 2018

Insurance [Abstract]

Schedule of Net Premiums Written and Earned

The following tables provide the total reinsurance balances recoverable as at September 30, 2018 and December 31, 2017:



	September 30, 2018
	Non-life Run-off			Atrium			StarStone			Total
Recoverable from reinsurers on unpaid:
Outstanding losses	$	932,142		$	13,051		$	214,963		$	1,160,156
IBNR	664,873			31,445			175,302			871,620
Fair value adjustments	(14,489		)	886			(1,550		)	(15,153		)
Fair value adjustments - fair value option	(170,436		)	—			—			(170,436		)
Total reinsurance reserves recoverable	1,412,090			45,382			388,715			1,846,187
Paid losses recoverable	108,218			(1,808		)	22,959			129,369
	$	1,520,308		$	43,574		$	411,674		$	1,975,556
Reconciliation to Consolidated Balance Sheet:
Reinsurance balances recoverable	$	727,755		$	43,574		$	411,674		$	1,183,003
Reinsurance balances recoverable - fair value option	792,553			—			—			792,553
Total	$	1,520,308		$	43,574		$	411,674		$	1,975,556



	December 31, 2017
	Non-life Run-off			Atrium			StarStone			Other		Total
Recoverable from reinsurers on unpaid:
Outstanding losses	$	932,284		$	7,472		$	211,650		$	16	$	1,151,422
IBNR	590,154			31,476			242,620			—		864,250
Fair value adjustments	(12,970		)	1,583			(2,253		)	—		(13,640		)
Fair value adjustments - fair value option	(131,983		)	—			—			—		(131,983		)
Total reinsurance reserves recoverable	1,377,485			40,531			452,017			16		1,870,049
Paid losses recoverable	128,253			(451		)	23,179			—		150,981
	$	1,505,738		$	40,080		$	475,196		$	16	$	2,021,030
Reconciliation to Consolidated Balance Sheet:
Reinsurance balances recoverable	$	963,514		$	40,080		$	475,196		$	16	$	1,478,806
Reinsurance balances recoverable - fair value option	542,224			—			—			—		542,224
Total	$	1,505,738		$	40,080		$	475,196		$	16	$	2,021,030



	September 30, 2018								December 31, 2017
	Gross		Provisions for Bad Debt		Net		Provisions as a % of Gross		Gross		Provisions for Bad Debt		Net		Provisions as a % of Gross
Reinsurers rated A- or above	$	1,600,220	$	54,960	$	1,545,260	3.4	%	$	1,252,887	$	51,115	$	1,201,772	4.1	%
Reinsurers rated below A-, secured	397,775		—		397,775		—	%	771,097		—		771,097		—	%
Reinsurers rated below A-, unsecured	135,987		103,466		32,521		76.1	%	162,259		114,098		48,161		70.3	%
Total	$	2,133,982	$	158,426	$	1,975,556	7.4	%	$	2,186,243	$	165,213	$	2,021,030	7.6	%



	Three Months Ended September 30,												Nine Months Ended September 30,
	2018						2017						2018						2017
	Premiums Written			Premiums Earned			Premiums Written			Premiums Earned			Premiums Written			Premiums Earned			Premiums Written			Premiums Earned
Non-life Run-off
Gross	$	9,912		$	17,746		$	11,751		$	9,345		$	16,354		$	54,044		$	13,956		$	15,353
Ceded	(5,134		)	(7,304		)	(284		)	(2,930		)	(13,137		)	(26,815		)	(503		)	(5,497		)
Net	$	4,778		$	10,442		$	11,467		$	6,415		$	3,217		$	27,229		$	13,453		$	9,856
Atrium
Gross	$	39,995		$	42,505		$	36,377		$	39,591		$	130,997		$	121,974		$	117,355		$	111,633
Ceded	(2,854		)	(5,528		)	(10,388		)	(6,818		)	(17,779		)	(15,252		)	(18,120		)	(14,260		)
Net	$	37,141		$	36,977		$	25,989		$	32,773		$	113,218		$	106,722		$	99,235		$	97,373
StarStone
Gross	$	282,525		$	281,467		$	200,007		$	217,833		$	888,867		$	761,694		$	651,107		$	636,137
Ceded	(62,799		)	(65,112		)	(102,958		)	(110,183		)	(269,339		)	(234,892		)	(319,658		)	(294,528		)
Net	$	219,726		$	216,355		$	97,049		$	107,650		$	619,528		$	526,802		$	331,449		$	341,609
Other
Gross	$	846		$	848		$	2,424		$	1,444		$	2,858		$	2,878		$	4,506		$	4,658
Ceded	(24		)	(25		)	(753		)	(257		)	13			(3		)	(860		)	(1,002		)
Net	$	822		$	823		$	1,671		$	1,187		$	2,871		$	2,875		$	3,646		$	3,656
Total
Gross	$	333,278		$	342,566		$	250,559		$	268,213		$	1,039,076		$	940,590		$	786,924		$	767,781
Ceded	(70,811		)	(77,969		)	(114,383		)	(120,188		)	(300,242		)	(276,962		)	(339,141		)	(315,287		)
Total	$	262,467		$	264,597		$	136,176		$	148,025		$	738,834		$	663,628		$	447,783		$	452,494

Goodwill and Intangible Assets (Tables)

9 Months Ended

Sep. 30, 2018

Goodwill, Intangible Assets, Intangible Assets Arising from Insurance Contracts Acquired in Business Combination, and Deferred Charges Disclosure [Abstract]

Schedule of Goodwill and Intangible Assets

The following table presents a reconciliation of the beginning and ending goodwill, intangible assets and the deferred charges during the nine months ended September 30, 2018:



	Goodwill		Intangible assets with a definite life - Other			Intangible assets with an indefinite life		Total			Intangible assets with a definite life - FVA			Other assets - Deferred Charges
Balance as at January 1, 2018	$	73,071	$	20,487		$	87,031	$	180,589		$	140,393		$	80,192
Acquired during the period	41,736		—			—		41,736			3,976			17,208
Amortization	—		(3,030		)	—		(3,030		)	(6,138		)	(10,381		)
Balance as at September 30, 2018	$	114,807	$	17,457		$	87,031	$	219,295		$	138,231		$	87,019

The gross carrying value, accumulated amortization and net carrying value of intangible assets by type and the deferred charges as at September 30, 2018 and December 31, 2017 were as follows:



	September 30, 2018									December 31, 2017
	Gross Carrying Value			Accumulated Amortization			Net Carrying Value			Gross Carrying Value			Accumulated Amortization			Net Carrying Value
Intangible assets with a definite life:
Fair value adjustments:
Losses and LAE liabilities	$	467,944		$	(351,396	)	$	116,548		$	462,455		$	(345,449	)	$	117,006
Reinsurance balances recoverable	(180,732		)	165,579			(15,153		)	(179,219		)	165,579			(13,640		)
Other Assets	(48,840		)	838			(48,002		)	(48,840		)	440			(48,400		)
Other Liabilities	85,845			(1,007		)	84,838			85,845			(418		)	85,427
Total	$	324,217		$	(185,986	)	$	138,231		$	320,241		$	(179,848	)	$	140,393
Other:
Distribution channel	$	20,000		$	(6,443	)	$	13,557		$	20,000		$	(5,444	)	$	14,556
Technology	15,000			(14,716		)	284			15,000			(13,210		)	1,790
Brand	7,000			(3,384		)	3,616			7,000			(2,859		)	4,141
Total	$	42,000		$	(24,543	)	$	17,457		$	42,000		$	(21,513	)	$	20,487
Intangible assets with an indefinite life:
Lloyd’s syndicate capacity	$	37,031		$	—		$	37,031		$	37,031		$	—		$	37,031
Licenses	19,900			—			19,900			19,900			—			19,900
Management contract	30,100			—			30,100			30,100			—			30,100
Total	$	87,031		$	—		$	87,031		$	87,031		$	—		$	87,031

Deferred charges on retroactive reinsurance	$	295,851		$	(208,832	)	$	87,019		$278,643			$	(198,451	)	$80,192

Intangible Assets Amortization

The following table provides a summary of the amortization recorded on the intangible assets for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Intangible asset amortization	$	3,922	$	3,105	$	9,168	$	5,353

Debt Obligations (Tables)

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Amounts of Loans Payable Outstanding, and Accrued Interest

Debt obligations as at September 30, 2018 and December 31, 2017 were as follows:



Facility	Origination Date	Term	September 30, 2018			December 31, 2017
Senior Notes	March 10, 2017	5 years	$	350,000		$	350,000
Less: Unamortized debt issuance costs			(2,030		)	(2,484		)
Total Senior Notes			347,970			347,516
EGL Revolving Credit Facility	August 16, 2018	5 years	46,500			—
Previous EGL Revolving Credit Facility	September 16, 2014	5 years	—			225,110
EGL Term Loan Facility	November 18, 2016	3 years	—			74,063
Total debt obligations			$	394,470		$	646,689

Interest Expense

The table below provides a summary of the total interest expense for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Interest expense on debt obligations	$	4,552	$	6,219	$	20,822	$	18,576
Funds withheld balances and other	88		191		751		2,275
Total interest expense	$	4,640	$	6,410	$	21,573	$	20,851

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28541-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
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-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21538-112644

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
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-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

Noncontrolling Interests (Tables)

9 Months Ended

Sep. 30, 2018

Noncontrolling Interest [Abstract]

Carrying Amount of Equity Attributable to Noncontrolling Interest

The following is a reconciliation of the beginning and ending carrying amount of the equity attributable to the RNCI as at September 30, 2018 and December 31, 2017:



	Nine Months Ended			For The Year Ended
	September 30, 2018			December 31, 2017
Balance at beginning of period	$	479,606		$	454,522
Dividends paid	—			(27,458		)
Net earnings (losses) attributable to RNCI	(20,097		)	19,619
Accumulated other comprehensive earnings (losses) attributable to RNCI	(396		)	1,945
Change in redemption value of RNCI	(785		)	30,978
Balance at end of period	$	458,328		$	479,606

Earnings Per Share (Tables)

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Comparison of Basic and Diluted Earnings per Share

The following table sets forth the computation of basic and diluted net earnings per ordinary share for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended					Nine Months Ended
	September 30,					September 30,
	2018			2017		2018			2017
Numerator:
Earnings (losses) attributable to Enstar Group Limited ordinary shareholders:
Net earnings (loss) from continuing operations	$	(15,965	)	$	35,498	$	(48,931	)	$	184,864
Net earnings (loss) from discontinued operations	—			3,495		—			(1,005		)
Net earnings (loss) attributable to Enstar Group Limited attributable to Enstar Group Limited ordinary shareholders	(15,965		)	38,993		(48,931		)	183,859
Denominator:
Weighted average ordinary shares outstanding — basic	21,440,914			19,392,120		20,444,634			19,384,897
Effect of dilutive securities:
Share-based compensation plans	143,833			90,118		129,313			58,239
Warrants	80,609			76,930		79,597			72,851
Weighted average ordinary shares outstanding — diluted	21,665,356			19,559,168		20,653,544			19,515,987

Earnings (losses) per ordinary share attributable to Enstar Group Limited:
Basic:
Net earnings (loss) from continuing operations	$	(0.74	)	$	1.83	$	(2.39	)	$	9.54
Net earnings (loss) from discontinued operations	—			0.18		$	—		$	(0.05	)
Net earnings (loss) per ordinary share	$	(0.74	)	$	2.01	$	(2.39	)	$	9.49
Diluted⁽¹⁾:
Net earnings (loss) from continuing operations	$	(0.74	)	$	1.81	$	(2.39	)	$	9.47
Net earnings (loss) from discontinued operations	—			0.18		$	—		$	(0.05	)
Net earnings (loss) per ordinary share	$	(0.74	)	$	1.99	$	(2.39	)	$	9.42

Share-Based Compensation and Pensions (Tables)

9 Months Ended

Sep. 30, 2018

Retirement Benefits [Abstract]

Schedule of Compensation Cost for Share-based Compensation Plans

The table below provides the expenses related to the share-based compensation plans, employee share purchase plan, and pension plans for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017

Share-based Compensation Expense	$	3,865	$	9,234	$	14,384	$	19,213

Employee Share Purchase Plan	$	115	$	86	$	325	$	252

Pension Expense	$	2,818	$	3,998	$	8,640	$	9,483

Related Party Transactions (Tables)

9 Months Ended

Sep. 30, 2018

Schedule of Related Party Transactions

As at September 30, 2018 and December 31, 2017, the RNCI on our balance sheet relating to these Trident co-investment transactions was as follows:



	September 30, 2018	December 31, 2017
Redeemable Noncontrolling Interest	439,255	459,649

The following table presents the amounts included in our consolidated balance sheet related to our related party transactions with Stone Point and its affiliated entities:



	September 30, 2018		December 31, 2017
Investments in funds managed by Stone Point	$	375,406	$	255,905
Investments in registered investment companies affiliated with entities owned by Trident or Stone Point	34,682		22,060
Investments managed by Eagle Point Credit Management and PRIMA Capital Advisors	252,017		183,448
Investments in funds managed by Sound Point Capital	37,254		27,429
Investments in CLO equity securities with Sound Point Capital as collateral manager	16,206		17,760
Separate account managed by Sound Point Capital	5,231		63,572
Total investments	$	720,796	$	570,174

The following table presents the amounts included in net earnings related to our related party transactions with Stone Point and its affiliated entities:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Net unrealized gains on funds managed by Stone Point	$	9,598		$	6,137		$	11,850		$	17,787
Net unrealized gains (losses) on registered investment companies affiliated with entities owned by Trident or Stone Point	(283		)	86			6,267			5,123
Interest income on registered investment companies affiliated with entities owned by Trident	707			1,138			2,617			2,412
Management fees on investments managed by Eagle Point Credit Management and PRIMA Capital Advisors	(242		)	(160		)	(696		)	(451		)
Net unrealized gains on investments in funds managed by Sound Point Capital	394			576			156			1,370
Net unrealized losses on investments in CLO equity securities with Sound Point Capital as collateral manager	(931		)	(1,090		)	(1,554		)	(3,584		)
Interest income on investments in CLO equity securities with Sound Point Capital as collateral manager	1,106			1,118			3,595			3,598
Management fees on separate account managed by Sound Point Capital	(6		)	(71		)	(167		)	(224		)
Total investment earnings	$	10,343		$	7,734		$	22,068		$	26,031

The reinsurance balances recoverable on our consolidated balance sheet as at September 30, 2018 and December 31, 2017 was as follows:



	September 30, 2018		December 31, 2017
Reinsurance balances recoverable	$	6,884	$	7,003

Our consolidated balance sheet as at September 30, 2018 and December 31, 2017 included the following balances related to transactions between us and Hillhouse and its affiliated entities:



	September 30, 2018		December 31, 2017
Investments in funds managed by Hillhouse, held by equity method investments	$	—	$	456,660

Investment in funds managed by Hillhouse	$	903,568	$	—



	September 30, 2018		December 31, 2017
Investment in Citco	$	49,606	$	—

Our investment in the common and preferred shares of Monument, carried in other assets on our consolidated balance sheet, as at September 30, 2018 and December 31, 2017 was as follows:



	September 30, 2018		December 31, 2017
Investment in Monument	$	35,587	$	15,960

Our investment in the common shares of Clear Spring, carried in other assets on our consolidated balance sheet, as at September 30, 2018 and December 31, 2017 was as follows:



	September 30, 2018		December 31, 2017
Investment in Clear Spring	$	10,565	$	10,596

Our consolidated balance sheet as at September 30, 2018 and December 31, 2017 included the following balances related to transactions between us and Clear Spring:



	September 30, 2018		December 31, 2017
Balances under StarStone quota share:
Reinsurance balances recoverable	$	19,192	$	9,053
Prepaid insurance premiums	12,215		13,747
Ceded payable	15,275		13,964
Ceded acquisition costs	2,920		3,186

Balances under Cavello Bay quota share:
Losses and LAE	4,682		2,231
Unearned reinsurance premiums	3,054		3,437
Funds held	8,744		5,095



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017

Transactions under StarStone quota share:
Ceded premium earned	$	(6,926	)	$	(8,393	)	$	(21,564	)	$	(8,393	)
Ceded incurred losses and LAE	3,823			2,068			12,429			2,068
Ceded acquisition costs	981			5,540			4,892			5,540

Transactions under Cavello Bay quota share:
Premium earned	3,482			2,098			5,391			2,098
Net incurred losses and LAE	(2,346		)	(1,385		)	(3,107		)	(1,385		)
Acquisition costs	(721		)	(1,198		)	(1,275		)	(1,198		)

Net income statement amounts	$	(1,707	)	$	(1,270	)	$	(3,234	)	$	(1,270	)

Our consolidated balance sheet as at December 31, 2017 included the following balances related to transactions between us and KaylaRe and KaylaRe Ltd.:



	December 31, 2017
Reinsurance balances recoverable	$	357,355
Prepaid reinsurance premiums	116,356
Funds held	174,181
Insurance and reinsurance balances payable	232,884
Ceded acquisition costs	36,070



	Nine Months Ended
	September 30,
	2018			2017
Management fee income	$	1,453		$	6,059

Transactions under KaylaRe-StarStone QS:
Ceded premium earned	(52,651		)	(170,552		)
Net incurred losses	31,654			127,578
Acquisition costs	18,774			67,375

Transactions under Fitzwilliam reinsurance agreement:
Profit Commission	—			11,525
Net incurred losses	—			(12,791		)

Net income statement gain (loss) amounts	$	(770	)	$	29,194

Segment Information (Tables)

9 Months Ended

Sep. 30, 2018

Segment Reporting [Abstract]

Summary of Operations by Segment

The following tables set forth selected and unaudited condensed consolidated statement of earnings results by segment for the three and nine months ended September 30, 2018 and 2017:



	Three Months Ended September 30, 2018
	Non-Life Run-Off			Atrium			StarStone			Other			Total
Gross premiums written	$	9,912		$	39,995		$	282,525		$	846		$	333,278

Net premiums written	$	4,778		$	37,141		$	219,726		$	822		$	262,467

Net premiums earned	$	10,442		$	36,977		$	216,355		$	823		$	264,597
Net incurred losses and LAE	62,778			(17,853		)	(198,899		)	—			(153,974		)
Life and Annuity Policy Benefits	—			—			—			(423		)	(423		)
Acquisition costs	160			(13,215		)	(41,079		)	(108		)	(54,242		)
Operating expenses	(37,473		)	(3,952		)	(38,000		)	—			(79,425		)
Underwriting income (loss)	35,907			1,957			(61,623		)	292			(23,467		)
Net investment income	59,247			1,597			9,504			(918		)	69,430
Net realized and unrealized gains (losses)	(58,506		)	194			989			100			(57,223		)
Fees and commission income	3,708			3,242			—			—			6,950
Other income (expense)	11,423			7			117			(4		)	11,543
Corporate expenses	(11,433		)	(2,770		)	—			(8,925		)	(23,128		)
Interest income (expense)	(5,951		)	—			—			1,311			(4,640		)
Net foreign exchange gains (losses)	17			(262		)	(585		)	(210		)	(1,040		)
EARNINGS (LOSS) BEFORE INCOME TAXES	34,412			3,965			(51,598		)	(8,354		)	(21,575		)
INCOME (TAXES) BENEFIT	(125		)	(737		)	118			(2		)	(746		)
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	34,287			3,228			(51,480		)	(8,356		)	(22,321		)
Net loss (earnings) attributable to noncontrolling interest	(1,659		)	(1,266		)	14,414			—			11,489
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	32,628			1,962			(37,066		)	(8,356		)	(10,832		)
Dividends on preferred shares	—			—			—			(5,133		)	(5,133		)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$	32,628		$	1,962		$	(37,066	)	$	(13,489	)	$	(15,965	)

Underwriting ratios⁽¹⁾:
Loss ratio				48.3		%	91.9		%
Acquisition expense ratio				35.7		%	19.0		%
Operating expense ratio				10.7		%	17.6		%
Combined ratio				94.7		%	128.5		%

⁽¹⁾Refer to "Underwriting Ratios" for a description of how these ratios are calculated.



	Nine Months Ended September 30, 2018
	Non-Life Run-Off			Atrium			StarStone			Other			Total
Gross premiums written	$	16,354		$	130,997		$	888,867		$	2,858		$	1,039,076

Net premiums written	$	3,217		$	113,218		$	619,528		$	2,871		$	738,834

Net premiums earned	$	27,229		$	106,722		$	526,802		$	2,875		$	663,628
Net incurred losses and LAE	205,890			(51,951		)	(420,266		)	—			(266,327		)
Life and Annuity Policy Benefits	—			—			—			(217		)	(217		)
Acquisition costs	(4,524		)	(37,996		)	(94,775		)	(389		)	(137,684		)
Operating expenses	(114,254		)	(12,259		)	(106,699		)	—			(233,212		)
Underwriting income (loss)	114,341			4,516			(94,938		)	2,269			26,188
Net investment income	168,189			4,067			25,950			4,012			202,218
Net realized and unrealized losses	(230,829		)	(1,889		)	(15,150		)	(6,803		)	(254,671		)
Fees and commission income	13,093			10,540			—			—			23,633
Other income (expense)	34,989			127			(432		)	(207		)	34,477
Corporate expenses	(33,453		)	(5,083		)	—			(28,677		)	(67,213		)
Interest income (expense)	(24,562		)	—			(547		)	3,536			(21,573		)
Net foreign exchange gains (losses)	(202		)	(1,262		)	(1,063		)	1,138			(1,389		)
EARNINGS (LOSS) BEFORE INCOME TAXES	41,566			11,016			(86,180		)	(24,732		)	(58,330		)
INCOME TAXES	(227		)	(1,756		)	(2,568		)	(13		)	(4,564		)
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	41,339			9,260			(88,748		)	(24,745		)	(62,894		)
Net loss (earnings) attributable to noncontrolling interest	(4,182		)	(3,798		)	27,076			—			19,096
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	37,157			5,462			(61,672		)	(24,745		)	(43,798		)
Dividends on preferred shares	—			—			—			(5,133		)	(5,133		)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$	37,157		$	5,462		$	(61,672	)	$	(29,878	)	$	(48,931	)

Underwriting ratios⁽¹⁾:
Loss ratio				48.7		%	79.8		%
Acquisition expense ratio				35.6		%	18.0		%
Operating expense ratio				11.5		%	20.2		%
Combined ratio				95.8		%	118.0		%

⁽¹⁾Refer to "Underwriting Ratios" for a description of how these ratios are calculated.



	Three Months Ended September 30, 2017
	Non-Life Run-Off			Atrium			StarStone			Other			Total
Gross premiums written	$	11,751		$	36,377		$	200,007		$	2,424		$	250,559

Net premiums written	$	11,467		$	25,989		$	97,049		$	1,671		$	136,176

Net premiums earned	$	6,415		$	32,773		$	107,650		$	1,187		$	148,025
Net incurred losses and LAE	70,882			(35,273		)	(111,321		)	—			(75,712		)
Life and Annuity Policy Benefits	—			—			—			(1,060		)	(1,060		)
Acquisition costs	(1,001		)	(11,818		)	(11,313		)	(149		)	(24,281		)
Operating expenses	(35,657		)	(2,507		)	(32,605		)	—			(70,769		)
Underwriting income (loss)	40,639			(16,825		)	(47,589		)	(22		)	(23,797		)
Net investment income	42,829			847			7,592			760			52,028
Net realized and unrealized gains (losses)	25,016			285			5,045			(1,045		)	29,301
Fees and commission income (expense)	10,762			5,911			—			(778		)	15,895
Other income (expense)	(4,018		)	69			91			10			(3,848		)
Corporate expenses	(20,326		)	37			—			(9,267		)	(29,556		)
Interest income (expense)	(6,664		)	(23		)	(382		)	659			(6,410		)
Net foreign exchange gains (losses)	(3,772		)	(43		)	1,145			(2,105		)	(4,775		)
Loss on sale of subsidiary	—			—			—			(6,740		)	(6,740		)
EARNINGS (LOSS) BEFORE INCOME TAXES	84,466			(9,742		)	(34,098		)	(18,528		)	22,098
INCOME (TAXES) BENEFIT	(970		)	(554		)	78			14			(1,432		)
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	83,496			(10,296		)	(34,020		)	(18,514		)	20,666
NET EARNINGS FROM DISCONTINUED OPERATIONS, NET OF INCOME TAX EXPENSE	—			—			—			3,495			3,495
NET EARNINGS (LOSS)	83,496			(10,296		)	(34,020		)	(15,019		)	24,161
Net loss (earnings) attributable to noncontrolling interest	(3,314		)	4,223			13,923			—			14,832
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$	80,182		$	(6,073	)	$	(20,097	)	$	(15,019	)	$	38,993

Underwriting ratios⁽¹⁾:
Loss ratio				107.6		%	103.4		%
Acquisition expense ratio				36.1		%	10.5		%
Operating expense ratio				7.6		%	30.3		%
Combined ratio				151.3		%	144.2		%

⁽¹⁾Refer to "Underwriting Ratios" for a description of how these ratios are calculated.



	Nine Months Ended September 30, 2017
	Non-Life Run-Off			Atrium			StarStone			Other			Total
Gross premiums written	$	13,956		$	117,355		$	651,107		$	4,506		$	786,924

Net premiums written	$	13,453		$	99,235		$	331,449		$	3,646		$	447,783

Net premiums earned	$	9,856		$	97,373		$	341,609		$	3,656		$	452,494
Net incurred losses and LAE	138,041			(55,950		)	(245,315		)	—			(163,224		)
Life and Annuity Policy Benefits	—			—			—			(5,048		)	(5,048		)
Acquisition costs	(455		)	(34,647		)	(39,625		)	(730		)	(75,457		)
Operating expenses	(96,767		)	(12,227		)	(99,576		)	—			(208,570		)
Underwriting income (loss)	50,675			(5,451		)	(42,907		)	(2,122		)	195
Net investment income	118,130			2,832			20,230			8,992			150,184
Net realized and unrealized gains (losses)	127,130			1,177			18,953			(7,563		)	139,697
Fees and commission income (expense)	30,302			17,353			1,166			(2,345		)	46,476
Other income	18,679			188			170			169			19,206
Corporate expenses	(66,468		)	(7,404		)	—			(26,841		)	(100,713		)
Interest income (expense)	(20,991		)	(559		)	(1,648		)	2,347			(20,851		)
Net foreign exchange losses	(6,709		)	(4,355		)	(1,563		)	(2,985		)	(15,612		)
Loss on sale of subsidiary	—			—			—			(16,349		)	(16,349		)
EARNINGS (LOSS) BEFORE INCOME TAXES	250,748			3,781			(5,599		)	(46,697		)	202,233
INCOME (TAXES) BENEFIT	(5,609		)	(1,278		)	3,648			5			(3,234		)
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	245,139			2,503			(1,951		)	(46,692		)	198,999
NET LOSS FROM DISCONTINUED OPERATIONS, NET OF INCOME TAX EXPENSE	—			—			—			(1,005		)	(1,005		)
NET EARNINGS (LOSS)	245,139			2,503			(1,951		)	(47,697		)	197,994
Net loss (earnings) attributable to noncontrolling interest	(13,944		)	(1,027		)	836			—			(14,135		)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$	231,195		$	1,476		$	(1,115	)	$	(47,697	)	$	183,859

Underwriting ratios⁽¹⁾:
Loss ratio				57.5		%	71.8		%
Acquisition expense ratio				35.6		%	11.6		%
Operating expense ratio				12.5		%	29.2		%
Combined ratio				105.6		%	112.6		%

⁽¹⁾Refer to "Underwriting Ratios" for a description of how these ratios are calculated.

Summary of Company's Assets by Segment



	September 30,			December 31,
	2018			2017
Assets by Segment:
Non-life Run-off	$	11,907,196		$	10,368,105
Atrium	598,072			556,637
StarStone	3,199,238			3,128,725
Other	(583,278		)	(447,045		)
Total assets	$	15,121,228		$	13,606,422

Significant Accounting Policies (Details) - Retained Earnings - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principle	$ (1,573)		$ 4,882
Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principle		$ (1,600)

Acquisitions - Additional Information (Detail) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
	May 14, 2018 USD ($) $ / shares shares	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	May 13, 2018	Dec. 31, 2017 USD ($)
Business Acquisition [Line Items]
Excess of purchase price over fair value of net assets acquired				$ 114,807		$ 73,071
Kayla Re
Business Acquisition [Line Items]
Shares issued (in shares) \| shares	2,007,017
Excess of purchase price over fair value of net assets acquired	$ 41,736
Acquisition purchase price, per share (in dollars per share) \| $ / shares	$ 206.65
Percent of voting interests acquired	51.80%
Price-to-book multiple	1.05
Equity interest in acquiree, remeasurement gain			$ 16,007	$ 16,000
Contractual preexisting relationships, remeasurement gain (loss)			$ (15,600)
Net consideration payable	$ 788,056
Net loss and loss adjustment expense reserves and unearned premium reserves assumed	$ 746,320
Ordinary Shares \| Kayla Re
Business Acquisition [Line Items]
Shares issued (in shares) \| shares	1,501,778
Series E Non-Voting Convertible Ordinary Shares \| Kayla Re
Business Acquisition [Line Items]
Shares issued (in shares) \| shares	505,239
Kayla Re
Business Acquisition [Line Items]
Ownership percentage					48.20%
Scenario, Forecast \| Maiden Re North America
Business Acquisition [Line Items]
Net consideration payable		$ 307,500
Net loss and loss adjustment expense reserves and unearned premium reserves assumed		$ 1,300,000

Acquisitions - Purchase Price and Fair Value of Assets Acquired (Detail) $ / shares in Units, $ in Thousands		3 Months Ended	9 Months Ended
	May 14, 2018 USD ($) $ / shares shares	Jun. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Purchase Price
Excess of purchase price over fair value of net assets acquired			$ 114,807		$ 73,071
Kayla Re
Purchase Price
Fair value of Enstar ordinary shares issued	$ 414,750
Fair value of previously held equity method investment	336,137
Adjustment for the fair value of preexisting relationships	37,169
Total purchase price	788,056
Net assets acquired at fair value (excluding preexisting relationships)	746,320
Excess of purchase price over fair value of net assets acquired	$ 41,736
Fair Value of Enstar Ordinary Shares Issued
Number of Enstar Ordinary shares issued (in shares) \| shares	2,007,017
Closing price of Enstar Ordinary shares (in dollars per share) \| $ / shares	$ 206.65
Fair Value of Previously Held Equity Method Investment
Price-to-book multiple	1.05
Gain recognized on remeasurement of previously held equity method investment to fair value		$ 16,007	$ 16,000
Kayla Re
Fair Value of Previously Held Equity Method Investment
Carrying value of previously held equity method investment prior to the close of the transaction	$ 320,100			$ 320,130	$ 309,800

Acquisitions - Loss On Settlement Of Contractual Preexisting Relationships (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	May 14, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
ASSETS
Funds held by reinsured companies	$ 254,029			$ 175,383
Deferred acquisition costs/Value of business acquired	125,132			64,984
TOTAL ASSETS	15,121,228			13,606,422
LIABILITIES
Losses and LAE	8,535,733	$ 8,608,387		7,398,088	$ 7,615,717	$ 7,641,384	$ 5,987,867
Unearned premiums	743,024			583,197
Insurance and reinsurance balances payable	381,114			236,697
Other liabilities	570,474			972,457
TOTAL LIABILITIES	10,747,223			9,980,868
NET ASSETS (LIABILITIES)	$ 3,915,677			$ 3,145,948
Carrying Value \| Kayla Re
ASSETS
Funds held by reinsured companies			$ 386,793
Deferred acquisition costs/Value of business acquired			33,549
TOTAL ASSETS			420,342
LIABILITIES
Losses and LAE			339,747
Unearned premiums			105,602
Insurance and reinsurance balances payable			25,897
Other liabilities			1,864
TOTAL LIABILITIES			473,110
NET ASSETS (LIABILITIES)			(52,768)
Fair Value \| Kayla Re
ASSETS
Funds held by reinsured companies			386,793
Deferred acquisition costs/Value of business acquired			40,268
TOTAL ASSETS			427,061
LIABILITIES
Losses and LAE			333,205
Unearned premiums			105,602
Insurance and reinsurance balances payable			23,559
Other liabilities			1,864
TOTAL LIABILITIES			464,230
NET ASSETS (LIABILITIES)			(37,169)
Fair Value Adjustments \| Kayla Re
ASSETS
Funds held by reinsured companies			0
Deferred acquisition costs/Value of business acquired			6,719
TOTAL ASSETS			6,719
LIABILITIES
Losses and LAE			(6,542)
Unearned premiums			0
Insurance and reinsurance balances payable			(2,338)
Other liabilities			0
TOTAL LIABILITIES			(8,880)
NET ASSETS (LIABILITIES)			$ 15,599

Acquisitions - Fair Values of Assets Acquired and Liabilities Assumed (Detail) - Kayla Re $ in Thousands	May 14, 2018 USD ($)
ASSETS
Fixed maturities, trading, at fair value	$ 126,393
Other investments	626,476
Total investments	752,869
Cash and cash equivalents	5,657
Premiums receivable	10,965
Deferred acquisition costs	275
Other assets	614
TOTAL ASSETS	770,380
LIABILITIES
Losses and LAE	4,059
Unearned premium	10,984
Insurance and reinsurance balances payable	13
Other liabilities	9,004
TOTAL LIABILITIES	24,060
NET ASSETS ACQUIRED AT FAIR VALUE	$ 746,320

Acquisitions - Results of Operations of Acquiree (Details) - Kayla Re $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Business Acquisition [Line Items]
Premiums earned	$ 10,188
Incurred losses and LAE	(9,190)
Acquisition costs	(332)
Underwriting income	666
Net investment income	1,972
Net unrealized gains	(6,621)
General and administrative expenses	(573)
Earnings of acquiree since acquisition date	$ (4,556)

Significant New Business - Additional Information (Detail) $ in Thousands, £ in Millions, $ in Millions									3 Months Ended		9 Months Ended
	Aug. 01, 2018 USD ($)	Feb. 23, 2018 AUD ($)	Feb. 23, 2018 USD ($)	Feb. 16, 2018 AUD ($)	Feb. 16, 2018 USD ($)	Feb. 16, 2018 GBP (£)	Jan. 29, 2018 USD ($)	Jan. 29, 2018 GBP (£)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Feb. 23, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Guarantor Obligations [Line Items]
Assumed business									$ 103,615	$ 0	$ 1,631,166	$ 1,432,412
Deferred charge									$ 87,019	$ 85,164	$ 87,019	$ 85,164	$ 71,393		$ 80,192	$ 88,475	$ 94,551
Coca-Cola
Guarantor Obligations [Line Items]
Assumed business	$ 120,800
Reinsurance premium consideration	103,600
Deferred charge	$ 17,200
Zurich
Guarantor Obligations [Line Items]
Assumed business		$ 359.4	$ 280,800
Reinsurance premium consideration		343.9	$ 268,700
Fair value adjustment on gross reserves		$ 15.5												$ 12,100
Neon
Guarantor Obligations [Line Items]
Assumed business					$ 546,300	£ 403.9
Net insurance reserves assumed					462,600	342.1
Reinsurance premium consideration				$ 445.1		£ 329.1
Fair value adjustment on gross reserves					20,600
Fair value adjustment of net reserves					$ 17,500
Novae
Guarantor Obligations [Line Items]
Assumed business							$ 1,163,200	£ 860.1
Net insurance reserves assumed							853,000	630.7
Reinsurance premium consideration							803,500	£ 594.1
Fair value adjustment on gross reserves							67,500
Fair value adjustment of net reserves							$ 49,500

Divestitures, Held-For-Sale Businesses and Discontinued Operations - Additional Information (Details) $ in Thousands, € in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 29, 2017 USD ($)	Aug. 29, 2017 USD ($)	Aug. 29, 2017 EUR (€)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	$ 0		$ 0			$ 24,351
Liabilities held for sale	0		0			11,271
Net loss from discontinued operations	0	$ (3,495)	0	$ 1,005
Loss on sale of subsidiary	0	6,740	0	16,349
Cumulative CTA adjustment	0	7,440	0	7,440
Pavonia \| Discontinued operations, held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal, consideration							$ 120,000
Disposal, restricted investments						1,400
Assets held for sale						24,351
Liabilities held for sale						$ 11,271
Net loss from discontinued operations		(3,495)		1,005
PLIC MI \| Discontinued operations, held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	23,300		23,300
Liabilities held for sale	$ 10,300		$ 10,300
Laguna \| Disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net loss from discontinued operations		900		1,100
Loss on sale of subsidiary		6,700		$ 16,300
Cumulative CTA adjustment		$ 6,300
Scenario, Forecast \| PLIC MI \| Discontinued operations, held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal, consideration					$ 13,100
Monument \| Affiliated Entity \| Laguna \| Disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal, consideration								$ 30,800	€ 25.6

Divestitures, Held-For-Sale Businesses and Discontinued Operations - Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
ASSETS
Total assets held for sale	$ 0		$ 0		$ 24,351
LIABILITIES
Total liabilities held for sale	0		0		11,271
EXPENSES
NET EARNINGS (LOSS) FROM DISCONTINUED OPERATIONS	$ 0	$ 3,495	0	$ (1,005)
Pavonia \| Discontinued operations, held-for-sale
ASSETS
Equities, trading, at fair value					765
Cash and cash equivalents					6,314
Restricted cash and cash equivalents					13
Reinsurance balances recoverable					1,728
Other assets					269
Assets of businesses held for sale					29,859
Less: Accrual of loss on sale					(5,508)
Total assets held for sale					24,351
LIABILITIES
Policy benefits for life and annuity contracts					10,666
Other liabilities					605
Total liabilities held for sale					11,271
INCOME
Net premiums earned		14,082		42,012
Net investment income		10,077		30,383
Net realized and unrealized gains (losses)		(233)		2,543
Other income		384		1,139
Total income		24,310		76,077
EXPENSES
Life and annuity policy benefits		15,320		60,102
Acquisition costs		2,412		6,728
General and administrative expenses		2,809		9,584
Other expenses		4		(12)
Total expenses		20,545		76,402
EARNINGS (LOSSES) BEFORE INCOME TAXES		3,765		(325)
INCOME TAXES		(270)		(680)
NET EARNINGS (LOSS) FROM DISCONTINUED OPERATIONS		$ 3,495		$ (1,005)
Net Cash Provided by (Used in) Discontinued Operations [Abstract]
Operating activities			42,558
Investing activities			8,129
Change in cash and cash equivalents			$ 50,687
Pavonia \| Discontinued operations, held-for-sale \| Fixed maturity investments
ASSETS
Fixed maturities, trading, at fair value					$ 20,770

Investments - Fair Values of Fixed Maturity Investments, Short-Term Investments and Equities Classified as Trading (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	$ 6,545,280
Equities, trading, at fair value	130,314	$ 106,603
Fair Value
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	6,545,280	5,876,284
Trading securities	6,675,594	5,982,887
U.S. government and agency \| Fair Value
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	493,080	554,036
Non-U.S. government \| Fair Value
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	1,018,212	607,132
Corporate \| Fair Value
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	3,703,029	3,363,060
Municipal \| Fair Value
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	76,599	100,221
Residential mortgage-backed \| Fair Value
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	275,485	288,713
Commercial mortgage-backed \| Fair Value
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	411,575	421,548
Asset-backed \| Fair Value
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	567,300	541,574
Equity securities \| Fair Value \| US
Debt and Equity Securities, FV-NI [Line Items]
Equities, trading, at fair value	72,765	106,363
Equity securities \| Fair Value \| Non-US
Debt and Equity Securities, FV-NI [Line Items]
Equities, trading, at fair value	57,549	240
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	147,300	152,400
Senior Secured Debt Securities
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	$ 24,300	$ 68,900

Investments - Contractual Maturities of Fixed Maturity and Short-term Investments Classified as Trading (Detail) $ in Thousands	Sep. 30, 2018 USD ($)
Amortized Cost
One year or less	$ 428,656
More than one year through two years	544,754
More than two years through five years	1,641,037
More than five years through ten years	1,506,829
More than ten years	1,301,979
Trading securities, amortized cost	6,689,097
Fair Value
One year or less	424,195
More than one year through two years	531,717
More than two years through five years	1,601,237
More than five years through ten years	1,464,185
More than ten years	1,269,586
Trading securities, debt	$ 6,545,280
% of Total Fair Value
One year or less	6.50%
More than one year through two years	8.10%
More than two years through five years	24.40%
More than five years through ten years	22.40%
More than ten years	19.40%
Trading securities, percentage of fair value	100.00%
Residential mortgage-backed
Amortized Cost
Securities without single maturity date	$ 274,833
Fair Value
Securities without single maturity date	$ 275,485
% of Total Fair Value
Securities without single maturity date	4.20%
Commercial mortgage-backed
Amortized Cost
Securities without single maturity date	$ 423,471
Fair Value
Securities without single maturity date	$ 411,575
% of Total Fair Value
Securities without single maturity date	6.30%
Asset-backed
Amortized Cost
Securities without single maturity date	$ 567,538
Fair Value
Securities without single maturity date	$ 567,300
% of Total Fair Value
Securities without single maturity date	8.70%

Investments - Amortized Cost and Fair Values of Fixed Maturity and Short-Term Investments Classified as Available-for-Sale (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 163,696	$ 208,097
Gross Unrealized Gains	1,936	3,693
Gross Unrealized Losses Non-OTTI	(2,488)	(1,505)
Fair Value	163,144	210,285
U.S. government and agency
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	703	4,210
Gross Unrealized Gains	0	0
Gross Unrealized Losses Non-OTTI	(5)	(23)
Fair Value	698	4,187
Non-U.S. government
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	75,741	84,776
Gross Unrealized Gains	851	1,249
Gross Unrealized Losses Non-OTTI	(1,036)	(588)
Fair Value	75,556	85,437
Corporate
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	83,836	113,561
Gross Unrealized Gains	1,085	2,436
Gross Unrealized Losses Non-OTTI	(1,413)	(876)
Fair Value	83,508	115,121
Municipal
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,401	5,146
Gross Unrealized Gains	0	8
Gross Unrealized Losses Non-OTTI	(34)	(18)
Fair Value	3,367	5,136
Residential mortgage-backed
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	15	31
Gross Unrealized Gains	0	0
Gross Unrealized Losses Non-OTTI	0	0
Fair Value	$ 15	31
Asset-backed
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		373
Gross Unrealized Gains		0
Gross Unrealized Losses Non-OTTI		0
Fair Value		$ 373

Investments - Contractual Maturities of Fixed Maturity and Short-Term Investments Classified as Available-for-Sale (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Amortized Cost
One year or less	$ 18,265
More than one year through two years	26,556
More than two years through five years	31,604
More than five years through ten years	55,804
More than ten years	31,452
Amortized Cost	163,696	$ 208,097
Fair Value
One year or less	17,641
More than one year through two years	26,332
More than two years through five years	31,634
More than five years through ten years	55,818
More than ten years	31,704
Fair Value	$ 163,144	210,285
% of Total Fair Value
One year or less	10.80%
More than one year through two years	16.20%
More than two years through five years	19.40%
More than five years through ten years	34.20%
More than ten years	19.40%
Percentage of Total Fair Value	100.00%
Residential mortgage-backed
Amortized Cost
Securities without single maturity date	$ 15
Amortized Cost	15	31
Fair Value
Securities without single maturity date	15
Fair Value	$ 15	$ 31
% of Total Fair Value
Securities without single maturity date	0.00%

Investments - Gross Unrealized Losses (Detail) $ in Thousands	Sep. 30, 2018 USD ($) Security	Dec. 31, 2017 USD ($) Security
Fair Value
12 Months or Greater	$ 14,110	$ 22,991
Less Than 12 Months	58,277	50,612
Total	72,387	73,603
Gross Unrealized Losses
12 Months or Greater	(1,340)	(1,201)
Less Than 12 Months	(1,148)	(304)
Total	$ (2,488)	$ (1,505)
Number of securities classified as available-for-sale in an unrealized loss position \| Security	103	96
Number of securities classified as available-for-sale in an unrealized loss position for twelve months or longer \| Security	33	37
U.S. government and agency
Fair Value
12 Months or Greater	$ 698	$ 2,344
Less Than 12 Months	0	1,842
Total	698	4,186
Gross Unrealized Losses
12 Months or Greater	(5)	(16)
Less Than 12 Months	0	(7)
Total	(5)	(23)
Non-U.S. government
Fair Value
12 Months or Greater	4,233	11,101
Less Than 12 Months	21,719	20,965
Total	25,952	32,066
Gross Unrealized Losses
12 Months or Greater	(406)	(373)
Less Than 12 Months	(630)	(215)
Total	(1,036)	(588)
Corporate
Fair Value
12 Months or Greater	8,562	9,177
Less Than 12 Months	33,808	24,200
Total	42,370	33,377
Gross Unrealized Losses
12 Months or Greater	(917)	(807)
Less Than 12 Months	(496)	(69)
Total	(1,413)	(876)
Municipal
Fair Value
12 Months or Greater	617	369
Less Than 12 Months	2,750	3,605
Total	3,367	3,974
Gross Unrealized Losses
12 Months or Greater	(12)	(5)
Less Than 12 Months	(22)	(13)
Total	$ (34)	$ (18)

Investments - Other Than Temporary Impairment (Details) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Other than temporary impairment losses, available-for-sale securities	$ 0	$ 0
Available-for-sale Securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Credit losses	$ 0		$ 0

Investments - Other Investments, at Fair Value (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	May 14, 2018	Dec. 31, 2017
Other Investments [Line Items]
Valuation lag period	3 months
Other investments, at fair value	$ 2,036,430			$ 913,392
Additional subscriptions	784,316	$ 98,203
Private equities and private equity funds
Other Investments [Line Items]
Other investments, at fair value	256,618			289,556
Unfunded commitments	$ 200,000
Fixed income funds
Other Investments [Line Items]
Imposed lock-up period (up to) (years)	2 years
Number of days to give notice for semi-annual redemption	65 days
Notice period	45 days
Gates or side-pocket investments	$ 300
Other investments, at fair value	383,328			229,999
Hedge funds
Other Investments [Line Items]
Other investments, at fair value	879,571			63,773
Equity funds
Other Investments [Line Items]
Other investments, at fair value	381,983			249,475
Unfunded commitments	200,000
CLO equities
Other Investments [Line Items]
Other investments, at fair value	48,368			56,765
CLO equity funds
Other Investments [Line Items]
Other investments, at fair value	41,501			12,840
Private credit funds
Other Investments [Line Items]
Other investments, at fair value	39,751			10,156
Call options on equity
Other Investments [Line Items]
Other investments, at fair value	4,590			0
Other
Other Investments [Line Items]
Other investments, at fair value	$ 720			$ 828
Hedge Funds, Fixed Income
Other Investments [Line Items]
Imposed lock-up period (up to) (years)	3 years
Number of days to give notice for quarterly hedge fund redemptions	90 days
Hedge Funds, Equity
Other Investments [Line Items]
Number of days to give notice for semi-annual redemption	60 days
CLO Equity Fund Two
Other Investments [Line Items]
Other investments, at fair value	$ 41,500
Kayla Re
Other Investments [Line Items]
Other investments acquired			$ 626,476
Affiliated Entity \| Kayla Re
Other Investments [Line Items]
Additional subscriptions	$ 538,100

Investments - Other Investments, at Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Other Investments [Line Items]
Amount of net investment income included in earnings attributable to investments in life settlements	$ 69,430	$ 52,028	$ 202,218	$ 150,184
Life Settlements
Other Investments [Line Items]
Amount of net investment income included in earnings attributable to investments in life settlements			6,500	10,600
Impairment charges recognized in the period			$ 6,600	$ 7,500

Investments - Net Investment Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net Investment Income [Line Items]
Gross investment income	$ 71,857	$ 54,649	$ 210,060	$ 158,458
Investment expenses	(2,427)	(2,621)	(7,842)	(8,274)
Net investment income	69,430	52,028	202,218	150,184
Fixed maturity investments
Net Investment Income [Line Items]
Net investment income	48,062	37,931	140,097	102,002
Short-term investments and cash and cash equivalents
Net Investment Income [Line Items]
Net investment income	3,247	2,048	8,425	7,489
Funds held
Net Investment Income [Line Items]
Net investment income	1,502	247	8,651	597
Funds held - directly managed
Net Investment Income [Line Items]
Gross investment income	10,056	8,791	28,828	25,220
Investment expenses	(280)	(275)	(838)	(1,099)
Net investment income	9,776	8,516	27,990	24,121
Fixed Maturities and Cash and Cash Equivalents
Net Investment Income [Line Items]
Net investment income	62,587	48,742	185,163	134,209
Equity securities
Net Investment Income [Line Items]
Net investment income	946	1,344	3,788	3,207
Other investments
Net Investment Income [Line Items]
Net investment income	8,324	3,120	14,600	10,016
Life settlements and other
Net Investment Income [Line Items]
Net investment income	0	1,443	6,509	11,026
Investment income from equities and other investments
Net Investment Income [Line Items]
Net investment income	$ 9,270	$ 5,907	$ 24,897	$ 24,249

Investments - Net Realized and Unrealized Gains (Losses) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net realized gains (losses) on sale:
Total net realized gains on sale	$ (10,037)	$ 5,360	$ (18,643)	$ 1,292
Net unrealized gains (losses):
Total net unrealized gains	(47,186)	23,941	(236,028)	138,405
Net realized and unrealized gains	(57,223)	29,301	(254,671)	139,697
Sales of available-for-sale securities	400	5,900	10,900	27,500
Fixed maturity securities
Net realized gains (losses) on sale:
Gross realized gains on fixed maturity securities, available-for-sale	0	8	27	345
Gross realized losses on fixed maturity securities, available-for-sale	(2)	(5)	(80)	(91)
Net realized gains (losses) on fixed maturity securities	(8,797)	4,595	(19,310)	3,608
Net unrealized gains (losses):
Net unrealized gains (losses) on trading securities	(13,423)	(10,747)	(159,691)	23,795
Equity securities
Net realized gains (losses) on sale:
Net realized gains on equity securities, trading	666	340	3,569	1,150
Net unrealized gains (losses):
Equity securities, trading	1,830	2,652	6,152	13,209
Other Investments
Net unrealized gains (losses):
Change in fair value of other investments	(35,188)	27,802	(37,059)	71,007
Change in fair value of embedded derivative	(182)	3,967	(41,107)	28,807
Funds held - directly managed
Net realized gains (losses) on sale:
Net realized gains (losses) on fixed maturity securities	(1,904)	422	(2,849)	(3,720)
Net unrealized gains (losses):
Change in fair value of embedded derivative	(182)	3,967	(41,107)	28,807
Change in value of fair value option on funds held - directly managed	(223)	267	(4,323)	1,587
Net realized and unrealized gains	$ (2,309)	$ 4,656	$ (48,279)	$ 26,674

Investments - Restricted Assets (Detail)	9 Months Ended
Investments - Restricted Assets (Detail)	Sep. 30, 2018 USD ($) Segment	Feb. 08, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)
Line of Credit Facility [Line Items]
Restricted cash and cash equivalents	$ 474,590,000		$ 257,686,000	$ 324,905,000
Collateral in trust for third party agreements	3,354,994,000		3,118,892,000
Assets on deposit with regulatory authorities	563,139,000		599,829,000
Funds at Lloyd's	422,657,000		234,833,000
Restricted assets, total	$ 4,475,076,000		4,105,021,000
Number of syndicates \| Segment	3
Cash and investments	$ 422,700,000
FAL Facility \| Line of Credit \| Letters of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	295,000,000	$ 325,000,000
Higher borrowing capacity option		$ 400,000,000
Asset Pledged as Collateral
Line of Credit Facility [Line Items]
Collateral for secured letter of credit facilities	$ 134,286,000		$ 151,467,000

Funds Held - Directly Managed - Additional Information (Details) - Allianz - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Schedule of Funds Held, Directly Managed [Line Items]
Funds held - directly managed, at cost, carrying value	$ 1,074.1	$ 994.8
Funds held - directly managed, fair value of embedded derivative	(36.3)	4.7
Funds held - directly managed	$ 1,037.8	$ 999.5

Funds Held - Directly Managed - Carrying Values of Assets and Liabilities Underlying Funds Held - Directly Managed (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Funds Held, Directly Managed [Line Items]
Fair Value	$ 6,545,280
Funds held - directly managed	1,217,182	$ 1,179,940
Funds held - directly managed, other assets
Schedule of Funds Held, Directly Managed [Line Items]
Fair Value	1,202,693	1,165,386
Funds held - directly managed, other assets	14,489	14,554
U.S. government and agency \| Funds held - directly managed, other assets
Schedule of Funds Held, Directly Managed [Line Items]
Fair Value	98,928	69,850
Non-U.S. government \| Funds held - directly managed, other assets
Schedule of Funds Held, Directly Managed [Line Items]
Fair Value	22,610	2,926
Corporate \| Funds held - directly managed, other assets
Schedule of Funds Held, Directly Managed [Line Items]
Fair Value	641,460	695,490
Municipal \| Funds held - directly managed, other assets
Schedule of Funds Held, Directly Managed [Line Items]
Fair Value	53,679	58,930
Residential mortgage-backed \| Funds held - directly managed, other assets
Schedule of Funds Held, Directly Managed [Line Items]
Fair Value	70,196	29,439
Commercial mortgage-backed \| Funds held - directly managed, other assets
Schedule of Funds Held, Directly Managed [Line Items]
Fair Value	220,077	211,186
Asset-backed \| Funds held - directly managed, other assets
Schedule of Funds Held, Directly Managed [Line Items]
Fair Value	$ 95,743	$ 97,565

Funds Held - Directly Managed - Contractual Maturities of Fixed Maturity Investments Underlying Funds Held - Directly Managed (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Amortized Cost
One year or less	$ 428,656
More than one year through two years	544,754
More than two years through five years	1,641,037
More than five years through ten years	1,506,829
More than ten years	1,301,979
Trading securities, amortized cost	6,689,097
Fair Value
One year or less	424,195
More than one year through two years	531,717
More than two years through five years	1,601,237
More than five years through ten years	1,464,185
More than ten years	1,269,586
Trading securities, debt	$ 6,545,280
% of Total Fair Value
One year or less	6.50%
More than one year through two years	8.10%
More than two years through five years	24.40%
More than five years through ten years	22.40%
More than ten years	19.40%
Trading securities, percentage of fair value	100.00%
Residential mortgage-backed
Amortized Cost
Securities without single maturity date	$ 274,833
Fair Value
Securities without single maturity date	$ 275,485
% of Total Fair Value
Securities without single maturity date	4.20%
Commercial mortgage-backed
Amortized Cost
Securities without single maturity date	$ 423,471
Fair Value
Securities without single maturity date	$ 411,575
% of Total Fair Value
Securities without single maturity date	6.30%
Asset-backed
Amortized Cost
Securities without single maturity date	$ 567,538
Fair Value
Securities without single maturity date	$ 567,300
% of Total Fair Value
Securities without single maturity date	8.70%
Funds held - directly managed
Amortized Cost
One year or less	$ 33,247
More than one year through two years	69,423
More than two years through five years	206,922
More than five years through ten years	287,706
More than ten years	246,045
Trading securities, amortized cost	1,242,539
Fair Value
One year or less	33,105
More than one year through two years	68,667
More than two years through five years	202,077
More than five years through ten years	277,396
More than ten years	235,432
Trading securities, debt	$ 1,202,693	$ 1,165,386
% of Total Fair Value
One year or less	2.80%
More than one year through two years	5.70%
More than two years through five years	16.80%
More than five years through ten years	23.10%
More than ten years	19.60%
Trading securities, percentage of fair value	100.00%
Funds held - directly managed \| Residential mortgage-backed
Amortized Cost
Securities without single maturity date	$ 71,876
Fair Value
Securities without single maturity date	70,196
Trading securities, debt	$ 70,196	29,439
% of Total Fair Value
Securities without single maturity date	5.80%
Funds held - directly managed \| Commercial mortgage-backed
Amortized Cost
Securities without single maturity date	$ 231,443
Fair Value
Securities without single maturity date	220,077
Trading securities, debt	$ 220,077	211,186
% of Total Fair Value
Securities without single maturity date	18.30%
Funds held - directly managed \| Asset-backed
Amortized Cost
Securities without single maturity date	$ 95,877
Fair Value
Securities without single maturity date	95,743
Trading securities, debt	$ 95,743	$ 97,565
% of Total Fair Value
Securities without single maturity date	7.90%

Funds Held - Directly Managed - Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net Investment Income [Line Items]
Gross investment income	$ 71,857	$ 54,649	$ 210,060	$ 158,458
Investment expenses	(2,427)	(2,621)	(7,842)	(8,274)
Net investment income	69,430	52,028	202,218	150,184
Funds held - directly managed
Net Investment Income [Line Items]
Gross investment income	10,056	8,791	28,828	25,220
Investment expenses	(280)	(275)	(838)	(1,099)
Net investment income	9,776	8,516	27,990	24,121
Funds held - directly managed \| Fixed maturity investments
Net Investment Income [Line Items]
Gross investment income	10,014	8,702	28,649	25,004
Funds held - directly managed \| Short-term investments and cash and cash equivalents
Net Investment Income [Line Items]
Gross investment income	$ 42	$ 89	$ 179	$ 216

Funds Held - Directly Managed - Net Realized and Unrealized Investment (Losses) Gains (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Gain (Loss) on Securities [Line Items]
Net realized and unrealized gains	$ (57,223)	$ 29,301	$ (254,671)	$ 139,697
Funds held - directly managed
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on fixed maturity securities	(1,904)	422	(2,849)	(3,720)
Change in fair value of embedded derivative	(182)	3,967	(41,107)	28,807
Change in value of fair value option on funds held - directly managed	(223)	267	(4,323)	1,587
Net realized and unrealized gains	$ (2,309)	$ 4,656	$ (48,279)	$ 26,674

Fair Value Measurements - Investments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reinsurance balances recoverable
Beginning fair value	$ 145,927	$ 175,466	$ 176,723	$ 178,317
Purchases	18,180	18,277	64,129	46,575
Sales	(35,184)	(5,169)	(103,417)	(38,386)
Total realized and unrealized gains (losses)	(6,452)	(3,151)	(9,628)	(9,675)
Transfer into Level 3 from Level 2	3,797	10,288	26,032	82,485
Transfer out of Level 3 into Level 2	(7,580)	(18,003)	(35,151)	(81,608)
Ending fair value	118,688	177,708	118,688	177,708
Corporate
Reinsurance balances recoverable
Beginning fair value	27,823	54,356	67,178	74,534
Purchases	205	2,510	12,008	18,078
Sales	(3,731)	(3,350)	(64,641)	(28,467)
Total realized and unrealized gains (losses)	92	(834)	29	(184)
Transfer into Level 3 from Level 2	292	5,670	15,551	10,615
Transfer out of Level 3 into Level 2	(1,302)	(5,193)	(6,746)	(21,417)
Ending fair value	23,379	53,159	23,379	53,159
Residential mortgage-backed
Reinsurance balances recoverable
Beginning fair value	0	693	3,080	0
Purchases	0	0	0	711
Sales	0	(33)	(1,184)	(38)
Total realized and unrealized gains (losses)	1	3	(32)	(10)
Transfer into Level 3 from Level 2	1,794	0	1,794	0
Transfer out of Level 3 into Level 2	0	(663)	(1,863)	(663)
Ending fair value	1,795	0	1,795	0
Commercial mortgage-backed
Reinsurance balances recoverable
Beginning fair value	15,326	22,865	21,494	12,213
Purchases	1,599	11,274	3,402	21,621
Sales	(3,271)	(602)	(4,998)	(1,336)
Total realized and unrealized gains (losses)	(726)	(398)	(674)	(67)
Transfer into Level 3 from Level 2	0	616	4,897	18,532
Transfer out of Level 3 into Level 2	(3,545)	(1,619)	(14,738)	(18,827)
Ending fair value	9,383	32,136	9,383	32,136
Asset-backed
Reinsurance balances recoverable
Beginning fair value	46,608	40,433	27,892	14,692
Purchases	16,376	4,350	45,967	5,730
Sales	(28,182)	(1,184)	(31,994)	(8,545)
Total realized and unrealized gains (losses)	(346)	(384)	(417)	(175)
Transfer into Level 3 from Level 2	(1)	4,002	2,078	53,338
Transfer out of Level 3 into Level 2	(2,733)	(10,528)	(11,804)	(28,351)
Ending fair value	31,722	36,689	31,722	36,689
Equities
Reinsurance balances recoverable
Beginning fair value	2,016	0	0	0
Purchases	0	0	2,000	0
Sales	0	0	0	0
Total realized and unrealized gains (losses)	0	0	16	0
Transfer into Level 3 from Level 2	1,712	0	1,712	0
Transfer out of Level 3 into Level 2	0	0	0	0
Ending fair value	3,728	0	3,728	0
Other Investments
Reinsurance balances recoverable
Beginning fair value	54,154	57,119	57,079	76,878
Purchases	0	143	752	435
Sales	0	0	(600)	0
Total realized and unrealized gains (losses)	(5,473)	(1,538)	(8,550)	(9,239)
Transfer into Level 3 from Level 2	0	0	0	0
Transfer out of Level 3 into Level 2	0	0	0	(12,350)
Ending fair value	$ 48,681	$ 55,724	$ 48,681	$ 55,724

Fair Value Measurements - Insurance Contracts (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reinsurance balances recoverable
Beginning fair value	$ 145,927	$ 175,466	$ 176,723	$ 178,317
Assumed business	18,180	18,277	64,129	46,575
Changes in fair value:
Ending fair value	118,688	177,708	118,688	177,708
Losses and LAE liabilities
Liability for losses and LAE
Beginning fair value	3,221,366	1,892,297	1,794,669	0
Assumed business	0	0	1,890,061	1,966,843
Changes in nominal amounts:
Net incurred losses and LAE	(19,973)	(22,711)	(75,169)	(55,356)
Paid losses	(149,132)	(36,466)	(453,180)	(136,519)
Changes in fair value:
Discounted cash flows	(2,811)	(6,826)	(23,674)	10,187
Risk margin	(7,762)	(3,845)	(26,508)	(12,897)
Effect of exchange rate movements	(21,967)	32,803	(86,478)	82,994
Ending fair value	3,019,721	1,855,252	3,019,721	1,855,252
Reinsurance balances recoverable
Reinsurance balances recoverable
Beginning fair value	837,373	554,759	542,224	0
Assumed business	0	0	372,780	565,824
Changes in nominal amounts:
Net incurred losses and LAE	1,085	(3,181)	3,469	(5,276)
Paid losses	(41,819)	(9,453)	(95,354)	(30,947)
Changes in fair value:
Discounted cash flows	483	730	(13,399)	9,143
Risk margin	(1,949)	(897)	(4,668)	(2,599)
Effect of exchange rate movements	(2,620)	3,790	(12,499)	9,603
Ending fair value	$ 792,553	$ 545,748	$ 792,553	$ 545,748

Fair Value Measurements - Observable and Unobservable Inputs (Details) - Internal Model - Recurring	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Losses and LAE liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average cost of capital	8.50%	8.50%
Duration	8 years 19 days	11 years 4 months 27 days
Reinsurance balances recoverable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Risk cost of capital	5.00%	5.00%
Duration	9 years 11 days	11 years 7 months 29 days
Measurement Input, Entity Credit Risk \| Losses and LAE liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit spread for non-performance risk	0.20%	0.20%

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Mar. 10, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, amortized cost	$ 394,470	$ 646,689
Carrying Value \| Life Settlement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Life settlements		125,600
Fair Value \| Life Settlement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Life settlements		131,900
Senior Notes Due 2022 \| Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	4.50%		4.50%
Debt, amortized cost	$ 347,970	$ 347,516
Debt, fair value	$ 351,500

Derivative and Hedging Instruments - Foreign Currency Hedging of Net Investments (Detail) € in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 EUR (€)
Derivative [Line Items]
Net gains (losses) on qualifying non-derivative hedges	$ (143,000)	$ 11,634,000	$ 1,258,000	$ 15,891,000
Not designated as hedging instrument \| Foreign exchange forward
Derivative [Line Items]
Gross Notional Amount	406,761,000		406,761,000		$ 283,586,000
Assets	785,000		785,000		308,000
Liabilities	5,775,000		5,775,000		5,769,000
Gains (Losses) on non-qualifying-hedges included in net earnings	3,787,000	(3,831,000)	19,122,000	(5,263,000)
Not designated as hedging instrument \| Foreign exchange forward \| AUD
Derivative [Line Items]
Gross Notional Amount	35,090,000		35,090,000		57,028,000
Assets	236,000		236,000		0
Liabilities	0		0		1,002,000
Gains (Losses) on non-qualifying-hedges included in net earnings	957,000	0	3,453,000	0
Not designated as hedging instrument \| Foreign exchange forward \| EUR
Derivative [Line Items]
Gross Notional Amount	29,035,000		29,035,000		19,235,000
Assets	71,000		71,000		46,000
Liabilities	500,000		500,000		455,000
Gains (Losses) on non-qualifying-hedges included in net earnings	458,000	0	1,815,000	(562,000)
Not designated as hedging instrument \| Foreign exchange forward \| GBP
Derivative [Line Items]
Gross Notional Amount	251,059,000		251,059,000		207,323,000
Assets	436,000		436,000		262,000
Liabilities	5,275,000		5,275,000		4,312,000
Gains (Losses) on non-qualifying-hedges included in net earnings	4,154,000	(3,831,000)	8,389,000	(4,701,000)
Not designated as hedging instrument \| Foreign exchange forward \| CAD
Derivative [Line Items]
Gross Notional Amount	91,577,000		91,577,000		0
Assets	42,000		42,000		0
Liabilities	0		0		0
Gains (Losses) on non-qualifying-hedges included in net earnings	(1,782,000)	0	5,465,000	0
Designated as Hedging Instrument \| Foreign exchange forward
Derivative [Line Items]
Gross Notional Amount	113,210,000		113,210,000		59,951,000
Assets	412,000		412,000		11,000
Liabilities	0		0		1,477,000
Net gains (losses) on qualifying derivative hedges	730,000	(2,281,000)	2,338,000	(2,959,000)
Designated as Hedging Instrument \| Foreign exchange forward \| AUD
Derivative [Line Items]
Gross Notional Amount	43,410,000		43,410,000		32,810,000
Assets	237,000		237,000		0
Liabilities	0		0		965,000
Net gains (losses) on qualifying derivative hedges	678,000	(1,243,000)	2,286,000	(1,805,000)
Designated as Hedging Instrument \| Foreign exchange forward \| EUR
Derivative [Line Items]
Gross Notional Amount	69,800,000		69,800,000		0
Assets	175,000		175,000		0
Liabilities	0		0		0
Net gains (losses) on qualifying derivative hedges	52,000	0	52,000	0
Designated as Hedging Instrument \| Foreign exchange forward \| CAD
Derivative [Line Items]
Gross Notional Amount	0		0		27,141,000
Assets	0		0		11,000
Liabilities	0		0		512,000
Net gains (losses) on qualifying derivative hedges	0	(1,038,000)	0	(1,154,000)
Net Investment Hedging
Derivative [Line Items]
Gross Notional Amount	0		0		$ 60,100,000	€ 50.0
Net gains (losses) on qualifying non-derivative hedges	$ 696,000	$ (1,785,000)	$ 3,144,000	$ (8,280,000)

Derivative and Hedging Instruments - Investments in Call Options on Equities (Details) - Call options on equity $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018 USD ($) derivative_instrument	Sep. 30, 2018 USD ($) derivative_instrument	Dec. 31, 2017 derivative_instrument
Derivative [Line Items]
Number of equity derivative instruments \| derivative_instrument	0	0	0
Not designated as hedging instrument
Derivative [Line Items]
Cost	$ 10.0	$ 10.0
Unrealized gain (loss) on equity securities	$ (0.4)	$ (5.4)

Reinsurance Balances Recoverable - Total Reinsurance Balances (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Effects of Reinsurance [Line Items]
Outstanding losses	$ 1,160,156		$ 1,151,422
IBNR	871,620		864,250
Fair value adjustments	(15,153)		(13,640)
Fair value adjustments - fair value option	(170,436)		(131,983)
Total reinsurance reserves recoverable	1,846,187		1,870,049	$ 1,998,001
Paid losses recoverable	129,369		150,981
Net	1,975,556		2,021,030
Reinsurance balances recoverable	1,183,003		1,478,806
Reinsurance balances recoverable - fair value option	792,553		542,224
Non-life Run-off
Effects of Reinsurance [Line Items]
Outstanding losses	932,142
IBNR	664,873
Fair value adjustments	(14,489)
Fair value adjustments - fair value option	(170,436)
Total reinsurance reserves recoverable	1,412,090	$ 1,462,139	1,377,485	1,475,855	$ 1,500,557	$ 1,000,953
Paid losses recoverable	108,218
Net	1,520,308
Reinsurance balances recoverable	727,755
Reinsurance balances recoverable - fair value option	792,553
Atrium
Effects of Reinsurance [Line Items]
Outstanding losses	13,051
IBNR	31,445
Fair value adjustments	886
Fair value adjustments - fair value option	0
Total reinsurance reserves recoverable	45,382	38,253	40,531	44,207	29,749	30,009
Paid losses recoverable	(1,808)
Net	43,574
Reinsurance balances recoverable	43,574
Reinsurance balances recoverable - fair value option	0
StarStone
Effects of Reinsurance [Line Items]
Outstanding losses	214,963
IBNR	175,302
Fair value adjustments	(1,550)
Fair value adjustments - fair value option	0
Total reinsurance reserves recoverable	388,715	$ 366,577	452,017	$ 477,939	$ 393,656	$ 357,231
Paid losses recoverable	22,959
Net	411,674
Reinsurance balances recoverable	411,674
Reinsurance balances recoverable - fair value option	$ 0
Operating Segments \| Non-life Run-off
Effects of Reinsurance [Line Items]
Outstanding losses			932,284
IBNR			590,154
Fair value adjustments			(12,970)
Fair value adjustments - fair value option			(131,983)
Total reinsurance reserves recoverable			1,377,485
Paid losses recoverable			128,253
Net			1,505,738
Reinsurance balances recoverable			963,514
Reinsurance balances recoverable - fair value option			542,224
Operating Segments \| Atrium
Effects of Reinsurance [Line Items]
Outstanding losses			7,472
IBNR			31,476
Fair value adjustments			1,583
Fair value adjustments - fair value option			0
Total reinsurance reserves recoverable			40,531
Paid losses recoverable			(451)
Net			40,080
Reinsurance balances recoverable			40,080
Reinsurance balances recoverable - fair value option			0
Operating Segments \| StarStone
Effects of Reinsurance [Line Items]
Outstanding losses			211,650
IBNR			242,620
Fair value adjustments			(2,253)
Fair value adjustments - fair value option			0
Total reinsurance reserves recoverable			452,017
Paid losses recoverable			23,179
Net			475,196
Reinsurance balances recoverable			475,196
Reinsurance balances recoverable - fair value option			0
Other
Effects of Reinsurance [Line Items]
Outstanding losses			16
IBNR			0
Fair value adjustments			0
Fair value adjustments - fair value option			0
Total reinsurance reserves recoverable			16
Paid losses recoverable			0
Net			16
Reinsurance balances recoverable			16
Reinsurance balances recoverable - fair value option			$ 0

Reinsurance Balances Recoverable - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	$ 1,975,556		$ 2,021,030
Increase (decrease) in reinsurance recoverable	305,434	$ 628,654
Non-Life Run-Off and StarStone Segment
Effects of Reinsurance [Line Items]
Increase (decrease) in reinsurance recoverable	$ (45,500)

Reinsurance Balances Recoverable - Summary of Provisions for Uncollectible Reinsurance Balances Recoverable by Rating of Reinsurer (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Effects of Reinsurance [Line Items]
Gross	$ 2,133,982	$ 2,186,243
Provisions for Bad Debt	158,426	165,213
Net	$ 1,975,556	$ 2,021,030
Provisions as a % of Gross	7.40%	7.60%
Reinsurers rated A- or above
Effects of Reinsurance [Line Items]
Gross	$ 1,600,220	$ 1,252,887
Provisions for Bad Debt	54,960	51,115
Net	$ 1,545,260	$ 1,201,772
Provisions as a % of Gross	3.40%	4.10%
Secured \| Reinsurers rated below A-
Effects of Reinsurance [Line Items]
Gross	$ 397,775	$ 771,097
Provisions for Bad Debt	0	0
Net	$ 397,775	$ 771,097
Provisions as a % of Gross	0.00%	0.00%
Unsecured \| Reinsurers rated below A-
Effects of Reinsurance [Line Items]
Gross	$ 135,987	$ 162,259
Provisions for Bad Debt	103,466	114,098
Net	$ 32,521	$ 48,161
Provisions as a % of Gross	76.10%	70.30%

Losses and Loss Adjustment Expenses - Total Losses and Loss Adjustment Expense Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Outstanding losses	$ 4,795,799		$ 3,855,043
IBNR	3,948,740		3,653,656
Fair value adjustments	(116,548)		(117,006)
Fair value adjustments - fair value option	(457,215)		(314,748)
ULAE	364,957		321,143
Total	8,535,733	$ 8,608,387	7,398,088	$ 7,615,717	$ 7,641,384	$ 5,987,867
Loss and loss adjustment expenses	5,516,012		5,603,419
Loss and loss adjustment expenses, at fair value	3,019,721		1,794,669
Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Outstanding losses	3,998,430		3,185,703
IBNR	3,072,291		2,903,927
Fair value adjustments	(120,916)		(125,998)
Fair value adjustments - fair value option	(457,215)		(314,748)
ULAE	340,165		300,588
Total	6,832,755	7,025,750	5,949,472	6,131,732	6,317,279	4,716,363
Loss and loss adjustment expenses	3,813,034		4,154,803
Loss and loss adjustment expenses, at fair value	3,019,721		1,794,669
Atrium
Liability for Claims and Claims Adjustment Expense [Line Items]
Outstanding losses	83,138		78,363
IBNR	152,462		150,508
Fair value adjustments	4,749		9,547
Fair value adjustments - fair value option	0		0
ULAE	2,418		2,455
Total	242,767	234,232	240,873	245,720	208,646	212,122
Loss and loss adjustment expenses	242,767		240,873
Loss and loss adjustment expenses, at fair value	0		0
StarStone
Liability for Claims and Claims Adjustment Expense [Line Items]
Outstanding losses	714,231		590,977
IBNR	723,987		599,221
Fair value adjustments	(381)		(555)
Fair value adjustments - fair value option	0		0
ULAE	22,374		18,100
Total	1,460,211	$ 1,348,405	1,207,743	$ 1,238,265	$ 1,115,459	$ 1,059,382
Loss and loss adjustment expenses	1,460,211		1,207,743
Loss and loss adjustment expenses, at fair value	$ 0		$ 0

Losses and Loss Adjustment Expenses - Reconciliation of Beginning and Ending Reserves for Losses and Loss Adjustment Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance as at beginning of period	$ 8,608,387	$ 7,641,384	$ 7,398,088	$ 5,987,867
Less: reinsurance reserves recoverable			1,870,049
Less: deferred charges on retroactive reinsurance	71,393	88,475	80,192	94,551
Net balance as at beginning of period	6,670,025	5,628,947	5,447,863	4,505,123
Net incurred losses and LAE:
Current period	219,050	147,846	468,064	314,791
Prior periods	(65,076)	(72,134)	(201,737)	(151,567)
Total net incurred losses and LAE	153,974	75,712	266,327	163,224
Net paid losses:
Current period	(24,266)	(15,928)	(62,843)	(40,820)
Prior periods	(296,709)	(215,173)	(937,846)	(670,117)
Net losses paid	(320,975)	(231,101)	(1,000,689)	(710,937)
Effect of exchange rate movement	(26,825)	55,712	(108,659)	139,448
Acquired on purchase of subsidiaries	22,713	3,282	366,519	3,282
Assumed business	103,615	0	1,631,166	1,432,412
Net balance as at September 30	6,602,527	5,532,552	6,602,527	5,532,552
Plus: reinsurance reserves recoverable	1,846,187	1,998,001	1,846,187	1,998,001
Plus: deferred charges on retroactive reinsurance	87,019	85,164	87,019	85,164
Balance as at September 30	8,535,733	7,615,717	8,535,733	7,615,717
Non-Life Run-off Segment, Atrium Segment, and Starstone Segment
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Less: reinsurance reserves recoverable	1,866,969	1,923,962	1,870,033	1,388,193
Non-life Run-off
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance as at beginning of period	7,025,750	6,317,279	5,949,472	4,716,363
Less: reinsurance reserves recoverable	1,462,139	1,500,557	1,377,485	1,000,953
Less: deferred charges on retroactive reinsurance	71,393	88,475	80,192	94,551
Net balance as at beginning of period	5,492,218	4,728,247	4,491,795	3,620,859
Net incurred losses and LAE:
Current period	10,017	30	15,476	1,205
Prior periods	(72,795)	(70,912)	(221,366)	(139,246)
Total net incurred losses and LAE	(62,778)	(70,882)	(205,890)	(138,041)
Net paid losses:
Current period	(2,713)	(33)	(3,304)	(404)
Prior periods	(193,057)	(135,981)	(641,361)	(436,594)
Net losses paid	(195,770)	(136,014)	(644,665)	(436,998)
Effect of exchange rate movement	(26,352)	46,080	(102,030)	120,592
Acquired on purchase of subsidiaries	22,713	3,282	173,538	3,282
Assumed business	103,615	0	1,620,898	1,401,019
Net balance as at September 30	5,333,646	4,570,713	5,333,646	4,570,713
Plus: reinsurance reserves recoverable	1,412,090	1,475,855	1,412,090	1,475,855
Plus: deferred charges on retroactive reinsurance	87,019	85,164	87,019	85,164
Balance as at September 30	6,832,755	6,131,732	6,832,755	6,131,732
Atrium
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance as at beginning of period	234,232	208,646	240,873	212,122
Less: reinsurance reserves recoverable	38,253	29,749	40,531	30,009
Net balance as at beginning of period	195,979	178,897	200,342	182,113
Net incurred losses and LAE:
Current period	20,033	37,284	56,514	66,563
Prior periods	(2,180)	(2,011)	(4,563)	(10,613)
Total net incurred losses and LAE	17,853	35,273	51,951	55,950
Net paid losses:
Current period	(8,080)	(5,139)	(25,699)	(14,799)
Prior periods	(8,230)	(8,992)	(27,488)	(25,826)
Net losses paid	(16,310)	(14,131)	(53,187)	(40,625)
Effect of exchange rate movement	(137)	1,474	(1,721)	4,075
Net balance as at September 30	197,385	201,513	197,385	201,513
Plus: reinsurance reserves recoverable	45,382	44,207	45,382	44,207
Balance as at September 30	242,767	245,720	242,767	245,720
StarStone
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance as at beginning of period	1,348,405	1,115,459	1,207,743	1,059,382
Less: reinsurance reserves recoverable	366,577	393,656	452,017	357,231
Net balance as at beginning of period	981,828	721,803	755,726	702,151
Net incurred losses and LAE:
Current period	189,000	110,532	396,074	247,023
Prior periods	9,899	789	24,192	(1,708)
Total net incurred losses and LAE	198,899	111,321	420,266	245,315
Net paid losses:
Current period	(13,473)	(10,756)	(33,840)	(25,617)
Prior periods	(95,422)	(70,200)	(268,997)	(207,697)
Net losses paid	(108,895)	(80,956)	(302,837)	(233,314)
Effect of exchange rate movement	(336)	8,158	(4,908)	14,781
Acquired on purchase of subsidiaries	0	0	192,981	0
Assumed business	0	0	10,268	31,393
Net balance as at September 30	1,071,496	760,326	1,071,496	760,326
Plus: reinsurance reserves recoverable	388,715	477,939	388,715	477,939
Balance as at September 30	$ 1,460,211	$ 1,238,265	$ 1,460,211	$ 1,238,265

Losses and Loss Adjustment Expenses - Net (Reduction) Increase in Ultimate Losses and Loss Adjustment Expense Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Prior Period
Net losses paid	$ 296,709	$ 215,173	$ 937,846	$ 670,117
Net incurred losses and LAE, prior period	(65,076)	(72,134)	(201,737)	(151,567)
Current Period
Net losses paid	24,266	15,928	62,843	40,820
Net incurred losses and LAE, current period	219,050	147,846	468,064	314,791
Total
Net losses paid	320,975	231,101	1,000,689	710,937
Net change in case and LAE reserves	(111,659)	(67,087)	(337,695)	(279,371)
Net change in IBNR reserves	(28,170)	(68,068)	(335,903)	(231,174)
Increase (reduction) in estimates of net ultimate losses	181,146	95,946	327,091	200,392
Increase in provisions for bad debt	0	242	0	(493)
Increase (reduction) in provisions for unallocated LAE	(22,880)	(14,727)	(44,711)	(39,763)
Amortization of deferred charges	1,582	3,311	10,381	9,387
Amortization of fair value adjustments	3,233	1,444	5,681	2,955
Changes in fair value - fair value option	(9,107)	(10,504)	(32,115)	(9,254)
Total net incurred losses and LAE	153,974	75,712	266,327	163,224
Non-life Run-off
Prior Period
Net losses paid	193,057	135,981	641,361	436,594
Net change in case and LAE reserves	(128,827)	(66,376)	(377,735)	(276,903)
Net change in IBNR reserves	(109,287)	(120,614)	(424,847)	(262,296)
Increase (reduction) in estimates of net ultimate losses	(45,057)	(51,009)	(161,221)	(102,605)
Increase in provisions for bad debt			0	(735)
Increase (reduction) in provisions for unallocated LAE	(24,460)	(16,203)	(48,723)	(41,557)
Amortization of deferred charges	1,582	3,311	10,381	9,387
Amortization of fair value adjustments	4,247	3,493	10,312	5,518
Changes in fair value - fair value option	(9,107)	(10,504)	(32,115)	(9,254)
Net incurred losses and LAE, prior period	(72,795)	(70,912)	(221,366)	(139,246)
Current Period
Net losses paid	2,713	33	3,304	404
Net change in case and LAE reserves	165	(16)	1,223	(32)
Net change in IBNR reserves	7,139	(152)	10,949	572
Increase (reduction) in estimates of net ultimate losses	10,017	(135)	15,476	944
Increase in provisions for bad debt			0	0
Increase (reduction) in provisions for unallocated LAE	0	165	0	261
Amortization of deferred charges	0	0	0	0
Amortization of fair value adjustments	0	0	0	0
Changes in fair value - fair value option	0	0	0	0
Net incurred losses and LAE, current period	10,017	30	15,476	1,205
Total
Net losses paid	195,770	136,014	644,665	436,998
Net change in case and LAE reserves	(128,662)	(66,392)	(376,512)	(276,935)
Net change in IBNR reserves	(102,148)	(120,766)	(413,898)	(261,724)
Increase (reduction) in estimates of net ultimate losses	(35,040)	(51,144)	(145,745)	(101,661)
Increase in provisions for bad debt	0	0	0	(735)
Increase (reduction) in provisions for unallocated LAE	(24,460)	(16,038)	(48,723)	(41,296)
Amortization of deferred charges	1,582	3,311	10,381	9,387
Amortization of fair value adjustments	4,247	3,493	10,312	5,518
Changes in fair value - fair value option	(9,107)	(10,504)	(32,115)	(9,254)
Total net incurred losses and LAE	(62,778)	(70,882)	(205,890)	(138,041)
Atrium
Prior Period
Net losses paid	8,230	8,992	27,488	25,826
Net change in case and LAE reserves	(4,142)	(2,781)	(9,695)	(7,904)
Net change in IBNR reserves	(5,539)	(6,273)	(18,254)	(26,631)
Increase (reduction) in estimates of net ultimate losses	(1,451)	(62)	(461)	(8,709)
Increase in provisions for bad debt	0	(96)	0	(96)
Increase (reduction) in provisions for unallocated LAE	(2)	75
Amortization of fair value adjustments	(727)	(1,928)	(4,102)	(1,808)
Net incurred losses and LAE, prior period	(2,180)	(2,011)	(4,563)	(10,613)
Current Period
Net losses paid	8,080	5,139	25,699	14,799
Net change in case and LAE reserves	3,596	3,020	9,597	7,616
Net change in IBNR reserves	8,357	28,798	21,218	43,810
Increase (reduction) in estimates of net ultimate losses	20,033	36,957	56,514	66,225
Increase in provisions for bad debt	0	338	0	338
Increase (reduction) in provisions for unallocated LAE	0	(11)
Amortization of fair value adjustments	0	0	0	0
Net incurred losses and LAE, current period	20,033	37,284	56,514	66,563
Total
Net losses paid	16,310	14,131	53,187	40,625
Net change in case and LAE reserves	(546)	239	(98)	(288)
Net change in IBNR reserves	2,818	22,525	2,964	17,179
Increase (reduction) in estimates of net ultimate losses	18,582	36,895	56,053	57,516
Increase in provisions for bad debt	0	242	0	242
Increase (reduction) in provisions for unallocated LAE	(2)	64	0	0
Amortization of deferred charges	0	0	0	0
Amortization of fair value adjustments	(727)	(1,928)	(4,102)	(1,808)
Changes in fair value - fair value option	0	0	0	0
Total net incurred losses and LAE	17,853	35,273	51,951	55,950
StarStone
Prior Period
Net losses paid	95,422	70,200	268,997	207,697
Net change in case and LAE reserves	(19,919)	(14,037)	(55,541)	(55,501)
Net change in IBNR reserves	(63,294)	(54,400)	(183,422)	(149,165)
Increase (reduction) in estimates of net ultimate losses	12,209	1,763	30,034	3,031
Increase (reduction) in provisions for unallocated LAE	(2,023)	(853)	(5,313)	(3,984)
Amortization of fair value adjustments	(287)	(121)	(529)	(755)
Net incurred losses and LAE, prior period	9,899	789	24,192	(1,708)
Current Period
Net losses paid	13,473	10,756	33,840	25,617
Net change in case and LAE reserves	37,468	13,103	94,456	53,353
Net change in IBNR reserves	134,454	84,573	258,453	162,536
Increase (reduction) in estimates of net ultimate losses	185,395	108,432	386,749	241,506
Increase (reduction) in provisions for unallocated LAE	3,605	2,100	9,325	5,517
Amortization of fair value adjustments	0	0	0	0
Net incurred losses and LAE, current period	189,000	110,532	396,074	247,023
Total
Net losses paid	108,895	80,956	302,837	233,314
Net change in case and LAE reserves	17,549	(934)	38,915	(2,148)
Net change in IBNR reserves	71,160	30,173	75,031	13,371
Increase (reduction) in estimates of net ultimate losses	197,604	110,195	416,783	244,537
Increase in provisions for bad debt	0	0	0	0
Increase (reduction) in provisions for unallocated LAE	1,582	1,247	4,012	1,533
Amortization of deferred charges	0	0	0	0
Amortization of fair value adjustments	(287)	(121)	(529)	(755)
Changes in fair value - fair value option	0	0	0	0
Total net incurred losses and LAE	$ 198,899	$ 111,321	$ 420,266	$ 245,315

Losses and Loss Adjustment Expenses - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Effects of Reinsurance [Line Items]
Net incurred losses and LAE	$ 153,974	$ 75,712	$ 266,327	$ 163,224
Net incurred losses and LAE, current period	219,050	147,846	468,064	314,791
Prior periods	(65,076)	(72,134)	(201,737)	(151,567)
Net losses paid	296,709	215,173	937,846	670,117
Non-life Run-off
Effects of Reinsurance [Line Items]
Net incurred losses and LAE	(62,778)	(70,882)	(205,890)	(138,041)
Net incurred losses and LAE, current period	10,017	30	15,476	1,205
Prior periods	(72,795)	(70,912)	(221,366)	(139,246)
Increase (reduction) in estimates of net ultimate losses	(45,057)	(51,009)	(161,221)	(102,605)
Increase (reduction) in provisions for unallocated LAE	(24,460)	(16,203)	(48,723)	(41,557)
Decrease in fair value - fair value option, Prior Period	9,107	10,504	32,115	9,254
Amortization of fair value adjustments	4,247	3,493	10,312	5,518
Net change in case and IBNR reserves		(187,000)
Net losses paid	193,057	135,981	641,361	436,594
Amortization of deferred charges	1,582	$ 3,311	10,381	9,387
Non-life Run-off \| Workers Compensation Business
Effects of Reinsurance [Line Items]
Net change in case and IBNR reserves	$ (238,100)		$ (802,600)	$ (539,200)

Policy Benefits for Life Contracts (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Insurance [Abstract]
Policy benefits for life contracts	$ 107,466	$ 117,207

Premiums Written and Earned - Schedule of Net Premiums Written and Earned (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Effects of Reinsurance [Line Items]
Gross, premiums written	$ 333,278	$ 250,559	$ 1,039,076	$ 786,924
Ceded, premiums written	(70,811)	(114,383)	(300,242)	(339,141)
Net, premiums written	262,467	136,176	738,834	447,783
Gross, premiums earned	342,566	268,213	940,590	767,781
Ceded premium earned	(77,969)	(120,188)	(276,962)	(315,287)
Net, premiums earned	264,597	148,025	663,628	452,494
Operating Segments \| Non-life Run-off
Effects of Reinsurance [Line Items]
Gross, premiums written	9,912	11,751	16,354	13,956
Ceded, premiums written	(5,134)	(284)	(13,137)	(503)
Net, premiums written	4,778	11,467	3,217	13,453
Gross, premiums earned	17,746	9,345	54,044	15,353
Ceded premium earned	(7,304)	(2,930)	(26,815)	(5,497)
Net, premiums earned	10,442	6,415	27,229	9,856
Operating Segments \| Atrium
Effects of Reinsurance [Line Items]
Gross, premiums written	39,995	36,377	130,997	117,355
Ceded, premiums written	(2,854)	(10,388)	(17,779)	(18,120)
Net, premiums written	37,141	25,989	113,218	99,235
Gross, premiums earned	42,505	39,591	121,974	111,633
Ceded premium earned	(5,528)	(6,818)	(15,252)	(14,260)
Net, premiums earned	36,977	32,773	106,722	97,373
Operating Segments \| StarStone
Effects of Reinsurance [Line Items]
Gross, premiums written	282,525	200,007	888,867	651,107
Ceded, premiums written	(62,799)	(102,958)	(269,339)	(319,658)
Net, premiums written	219,726	97,049	619,528	331,449
Gross, premiums earned	281,467	217,833	761,694	636,137
Ceded premium earned	(65,112)	(110,183)	(234,892)	(294,528)
Net, premiums earned	216,355	107,650	526,802	341,609
Other
Effects of Reinsurance [Line Items]
Gross, premiums written	846	2,424	2,858	4,506
Ceded, premiums written	(24)	(753)	13	(860)
Net, premiums written	822	1,671	2,871	3,646
Gross, premiums earned	848	1,444	2,878	4,658
Ceded premium earned	(25)	(257)	(3)	(1,002)
Net, premiums earned	$ 823	$ 1,187	$ 2,875	$ 3,656

Goodwill and Intangible Assets - Schedule of Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Goodwill [Roll Forward]
Goodwill, Beginning balance			$ 73,071
Goodwill, Acquired during the period			41,736
Goodwill, Ending balance	$ 114,807		114,807
Finite-lived Intangible Assets [Roll Forward]
Intangible assets with a definite life - other, Beginning balance			20,487
Intangible assets with a definite life - other, Acquired during the period			0
Intangible assets with a definite life - other, Amortization			(3,030)
Intangible assets with a definite life - other, Ending balance	17,457		17,457
Indefinite-lived Intangible Assets [Roll Forward]
Intangible assets with an indefinite life, Beginning balance			87,031
Intangible assets with an indefinite life, Acquired during the period			0
Intangible assets with an indefinite life, Ending balance	87,031		87,031
Goodwill and Intangible Assets [Roll Forward]
Goodwill and intangible assets, Beginning Balance			180,589
Goodwill and intangible assets, Acquired during the period			41,736
Goodwill and intangible assets, Ending balance	219,295		219,295
Movement in Intangible Assets Arising from Insurance Contracts Acquired in Business Combination [Roll Forward]
Intangible assets with a definite life - FVA, Beginning balance			140,393
Intangible assets with a definite life - FVA, Acquired during the period			3,976
Intangible assets with a definite life - FVA, Amortization			(6,138)
Intangible assets with a definite life - FVA, Ending balance	138,231		138,231
Deferred Charges [Roll Forward]
Less: deferred charges on retroactive reinsurance	71,393	$ 88,475	80,192	$ 94,551
Other assets - Deferred Charges, Acquired during the period			17,208
Other assets - Deferred Charges, Amortization	(1,582)	(3,311)	(10,381)	(9,387)
Plus: deferred charges on retroactive reinsurance	$ 87,019	$ 85,164	$ 87,019	$ 85,164

Goodwill and Intangible Assets - Intangible Asset Amortization (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Goodwill, Intangible Assets, Intangible Assets Arising from Insurance Contracts Acquired in Business Combination, and Deferred Charges Disclosure [Abstract]
Amortization of intangible assets	$ 3,922	$ 3,105	$ 9,168	$ 5,353

Goodwill and Intangible Assets - Summary of Gross Carrying Value, Accumulated Amortization and Net Carrying Value of Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Fair value adjustments:
Gross Carrying Value	$ 324,217		$ 320,241
Accumulated Amortization	(185,986)		(179,848)
Net Carrying Value	138,231		140,393
Other:
Gross Carrying Value	42,000		42,000
Accumulated Amortization	(24,543)		(21,513)
Net Carrying Value	17,457		20,487
Indefinite-lived Intangible Assets [Line Items]
Intangible assets with an indefinite life, Carrying Value	87,031		87,031
Deferred charges on retroactive reinsurance, Gross Carrying Value	295,851		278,643
Deferred charges on retroactive reinsurance, Accumulated Amortization	(208,832)		(198,451)
Deferred charges on retroactive reinsurance, Net Carrying Value	87,019	$ 71,393	80,192	$ 85,164	$ 88,475	$ 94,551
Lloyd’s syndicate capacity
Indefinite-lived Intangible Assets [Line Items]
Intangible assets with an indefinite life, Carrying Value	37,031		37,031
Licenses
Indefinite-lived Intangible Assets [Line Items]
Intangible assets with an indefinite life, Carrying Value	19,900		19,900
Management contract
Indefinite-lived Intangible Assets [Line Items]
Intangible assets with an indefinite life, Carrying Value	30,100		30,100
Losses and LAE liabilities
Fair value adjustments:
Gross Carrying Value	467,944		462,455
Accumulated Amortization	(351,396)		(345,449)
Net Carrying Value	116,548		117,006
Reinsurance balances recoverable
Fair value adjustments:
Gross Carrying Value	(180,732)		(179,219)
Accumulated Amortization	165,579		165,579
Net Carrying Value	(15,153)		(13,640)
Other Assets
Fair value adjustments:
Gross Carrying Value	(48,840)		(48,840)
Accumulated Amortization	838		440
Net Carrying Value	(48,002)		(48,400)
Other Liabilities
Fair value adjustments:
Gross Carrying Value	85,845		85,845
Accumulated Amortization	(1,007)		(418)
Net Carrying Value	84,838		85,427
Distribution channel
Other:
Gross Carrying Value	20,000		20,000
Accumulated Amortization	(6,443)		(5,444)
Net Carrying Value	13,557		14,556
Technology
Other:
Gross Carrying Value	15,000		15,000
Accumulated Amortization	(14,716)		(13,210)
Net Carrying Value	284		1,790
Brand
Other:
Gross Carrying Value	7,000		7,000
Accumulated Amortization	(3,384)		(2,859)
Net Carrying Value	$ 3,616		$ 4,141

Debt Obligations - Amounts Outstanding and Accrued Interest (Detail) - USD ($)		3 Months Ended		9 Months Ended
	Sep. 16, 2014	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Mar. 10, 2017
Debt Instrument [Line Items]
Total debt obligations		$ 394,470,000		$ 394,470,000		$ 646,689,000
Interest expense on debt obligations		4,552,000	$ 6,219,000	20,822,000	$ 18,576,000
Funds withheld balances and other		88,000	191,000	751,000	2,275,000
Total interest expense		4,640,000	$ 6,410,000	$ 21,573,000	$ 20,851,000
Senior Notes \| Senior Notes Due 2022
Debt Instrument [Line Items]
Term				5 years
Senior Notes		350,000,000		$ 350,000,000		350,000,000	$ 350,000,000
Less: Unamortized debt issuance costs		(2,030,000)		(2,030,000)		(2,484,000)
Total debt obligations		347,970,000		$ 347,970,000		347,516,000
Line of Credit \| EGL Revolving Credit Facility
Debt Instrument [Line Items]
Term	5 years			5 years
Total debt obligations		46,500,000		$ 46,500,000		0
Line of Credit \| Previous EGL Revolving Credit Facility
Debt Instrument [Line Items]
Term				5 years
Total debt obligations		0		$ 0		225,110,000
Line of Credit \| EGL Term Loan Facility
Debt Instrument [Line Items]
Term				3 years
Total debt obligations		$ 0		$ 0		$ 74,063,000

Debt Obligations - Additional Information (Detail) € in Millions			1 Months Ended	9 Months Ended
	Mar. 10, 2017 USD ($)	Sep. 16, 2014	Nov. 07, 2018 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Aug. 16, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 EUR (€)	Nov. 18, 2016 USD ($)
Line of Credit Facility [Line Items]
Repayment of loans				$ 689,819,000	$ 564,203,000
Debt, amortized cost				394,470,000			$ 646,689,000
Net investment hedging
Line of Credit Facility [Line Items]
Derivative notional amount				0			60,100,000	€ 50.0
Senior Notes \| Senior Notes Due 2022
Line of Credit Facility [Line Items]
Outstanding amount of debt	$ 350,000,000			$ 350,000,000			350,000,000
Stated interest rate	4.50%			4.50%
Redemption price percentage	100.00%
Payments of debt issuance costs	$ 2,900,000
Term				5 years
Debt, amortized cost				$ 347,970,000			347,516,000
Line of Credit \| 2018 EGL Revolving Credit Facility
Line of Credit Facility [Line Items]
Term		5 years		5 years
Maximum borrowing capacity				$ 600,000,000		$ 600,000,000
Optional increase in borrowing capacity						$ 400,000,000
Line of credit facility, remaining borrowing capacity				553,500,000
Consolidated deb to total capitalization (not greater than)						0.35
Net income (loss) threshold						$ 2,300,000,000
Net income threshold percentage						50.00%
Percentage of proceeds of common stock issuance						50.00%
Debt, amortized cost				$ 46,500,000			0
Line of Credit \| 2018 EGL Revolving Credit Facility \| Subsequent Event
Line of Credit Facility [Line Items]
Line of credit facility, remaining borrowing capacity			$ 563,500,000
Repayment of loans			$ 10,000,000
Line of Credit \| EGL Term Loan Facility
Line of Credit Facility [Line Items]
Term				3 years
Maximum borrowing capacity									$ 75,000,000
Debt, amortized cost				$ 0			$ 74,063,000

Noncontrolling Interests - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Noncontrolling Interest [Line Items]
Noncontrolling interest	$ 10,313	$ 9,264
Trident \| Subsidiaries
Noncontrolling Interest [Line Items]
Interest owned by an entity (percent)	39.30%	39.30%
Dowling \| Subsidiaries
Noncontrolling Interest [Line Items]
Interest owned by an entity (percent)	1.70%	1.70%

Noncontrolling Interests - Carrying Amount of Equity Attributable to Noncontrolling Interest (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Increase (Decrease) in Redeemable Noncontrolling Interest [Roll Forward]
Balance at beginning of period	$ 479,606	$ 454,522
Dividends paid	0	(27,458)
Net earnings (losses) attributable to RNCI	(20,097)	19,619
Accumulated other comprehensive earnings (losses) attributable to RNCI	(396)	1,945
Change in redemption value of RNCI	(785)	30,978
Balance at end of period	$ 458,328	$ 479,606

Share Capital - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands					9 Months Ended
	Nov. 06, 2018	Jul. 31, 2018	Jun. 28, 2018	May 14, 2018	Sep. 30, 2018	Sep. 30, 2017
Class of Stock [Line Items]
Net proceeds from issuance of stock					$ 389,219	$ 0
Series D Preferred Stock
Class of Stock [Line Items]
Declared cash dividends (in dollars per share)		$ 320.83
Declared cash dividends (in dollars per depositary share)		$ 0.32083
Public Stock Offering \| Series D Preferred Stock
Class of Stock [Line Items]
Amount raised through public offering			$ 400,000
Shares issued in public offering (in shares)			16,000
Dividend rate, percentage			7.00%
Depositary interest in preferred shares, per share			$ 0.001
Shares issued in public offering (in depositary shares)			16,000,000
Preferred stock, par value (in dollars per share)			$ 1
Liquidation preference (in dollars per share)			25,000
Liquidation preference (in dollars per depositary share)			$ 25
Net proceeds from issuance of stock			$ 389,200
Dividends in arrears per share (in dollars per share)			$ 1,750
Dividends in arrears per share (in dollars per depositary share)			$ 1.75
Kayla Re
Class of Stock [Line Items]
Shares issued (in shares)				2,007,017
Ordinary Shares \| Kayla Re
Class of Stock [Line Items]
Shares issued (in shares)				1,501,778
Series E Non-Voting Convertible Ordinary Shares \| Kayla Re
Class of Stock [Line Items]
Shares issued (in shares)				505,239
LIBOR \| Public Stock Offering \| Series D Preferred Stock
Class of Stock [Line Items]
Basis spread on variable rate			4.015%
Subsequent Event \| Series D Preferred Stock
Class of Stock [Line Items]
Declared cash dividends (in dollars per share)	$ 437.5
Declared cash dividends (in dollars per depositary share)	$ 0.4375

Earnings Per Share - Comparison of Basic and Diluted Earnings per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator:
Net earnings (loss) from continuing operations	$ (15,965)	$ 35,498	$ (48,931)	$ 184,864
Net earnings (loss) from discontinued operations	0	3,495	0	(1,005)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$ (15,965)	$ 38,993	$ (48,931)	$ 183,859
Weighted-average ordinary shares outstanding — basic (in shares)	21,440,914	19,392,120	20,444,634	19,384,897
Effect of dilutive securities:
Share-based compensation plans (in shares)	143,833	90,118	129,313	58,239
Warrants (in shares)	80,609	76,930	79,597	72,851
Weighted-average ordinary shares outstanding — diluted (in shares)	21,665,356	19,559,168	20,653,544	19,515,987
Basic:
Net earnings (loss) from continuing operations (in dollars per share)	$ (0.74)	$ 1.83	$ (2.39)	$ 9.54
Net loss from discontinued operations (in dollars per share)	0.00	0.18	0.00	(0.05)
Net earnings (loss) per ordinary share (in dollars per share)	(0.74)	2.01	(2.39)	9.49
Diluted:
Net earnings (loss) from continuing operations (in dollars per share)	(0.74)	1.81	(2.39)	9.47
Net loss from discontinued operations (in dollars per share)	0.00	0.18	0.00	(0.05)
Net earnings (loss) per ordinary share (in dollars per share)	$ (0.74)	$ 1.99	$ (2.39)	$ 9.42

Share-Based Compensation and Pensions (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pension expense	$ 2,818	$ 3,998	$ 8,640	$ 9,483
Restricted Stock And Stock Appreciation Rights SARS
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	3,865	9,234	14,384	19,213
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 115	$ 86	$ 325	$ 252

Taxation - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
Taxation - Additional Information (Detail) - USD ($)	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective tax rate	(3.50%)	6.50%	(7.80%)	1.60%
Statutory rate			0.00%
Unrecognized tax benefits	$ 0		$ 0		$ 0

Related Party Transactions - Stone Point Capital LLC (Details) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Jul. 31, 2012 shares	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Nov. 06, 2013 general_partner
Related Party Transaction [Line Items]
Redeemable noncontrolling interest	$ 458,328			$ 458,328		$ 479,606	$ 454,522
Related Party, Consolidated Balance Sheet [Abstract]
Other investments, at fair value	2,036,430			2,036,430		913,392
Investments in registered investment companies affiliated with entities owned by Trident or Stone Point	130,314			130,314		106,603
Related Party, Consolidated Statement of Earnings [Abstract]
Net realized and unrealized gains (losses)	(57,223)	$ 29,301		(254,671)	$ 139,697
CLO equities
Related Party, Consolidated Balance Sheet [Abstract]
Other investments, at fair value	48,368			48,368		56,765
Affiliated Entity
Related Party, Consolidated Balance Sheet [Abstract]
Total investments	720,796			720,796		570,174
Trident \| Affiliated Entity
Related Party Transaction [Line Items]
Related party transaction, shares acquired \| shares			1,635,986
Number of newly elected board of directors \| general_partner								1
Number of general partners \| general_partner								4
Redeemable noncontrolling interest	439,255			439,255		459,649
Related Party, Consolidated Balance Sheet [Abstract]
Other investments, at fair value	375,406			375,406		255,905
Investments in registered investment companies affiliated with entities owned by Trident or Stone Point	34,682			34,682		22,060
Trident \| Affiliated Entity \| Fund Investments
Related Party, Consolidated Statement of Earnings [Abstract]
Net realized and unrealized gains (losses)	9,598	6,137		11,850	17,787
Trident \| Affiliated Entity \| Registered Investment Companies
Related Party, Consolidated Statement of Earnings [Abstract]
Net realized and unrealized gains (losses)	(283)	86		6,267	5,123
Interest income	707	1,138		2,617	2,412
Eagle Point Credit and PRIMA Capital Advisors \| Affiliated Entity
Related Party, Consolidated Balance Sheet [Abstract]
Separate account assets and investments	252,017			252,017		183,448
Eagle Point Credit and PRIMA Capital Advisors \| Affiliated Entity \| Management Fee
Related Party, Consolidated Statement of Earnings [Abstract]
Management fees	(242)	(160)		(696)	(451)
Sound Point Capital \| Affiliated Entity
Related Party, Consolidated Balance Sheet [Abstract]
Other investments, at fair value	37,254			37,254		27,429
Separate account assets and investments	5,231			5,231		63,572
Related Party, Consolidated Statement of Earnings [Abstract]
Net realized and unrealized gains (losses)	394	576		156	1,370
Sound Point Capital \| Affiliated Entity \| CLO equities
Related Party, Consolidated Balance Sheet [Abstract]
Other investments, at fair value	16,206			16,206		$ 17,760
Related Party, Consolidated Statement of Earnings [Abstract]
Net realized and unrealized gains (losses)	(931)	(1,090)		(1,554)	(3,584)
Interest income	1,106	1,118		3,595	3,598
Sound Point Capital \| Affiliated Entity \| Management Fee
Related Party, Consolidated Statement of Earnings [Abstract]
Management fees	(6)	(71)		(167)	(224)
StonePoint And Affiliated Entities \| Affiliated Entity
Related Party, Consolidated Statement of Earnings [Abstract]
Total investment earnings	$ 10,343	$ 7,734		$ 22,068	$ 26,031
Stone Point \| Affiliated Entity
Related Party Transaction [Line Items]
Ownership percentage	9.10%			9.10%

Related Party Transactions - CPPIB (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Affiliated Entity \| CPPIB LP
Related Party Transaction [Line Items]
Ownership percentage	4.10%
Affiliated Entity \| CPPIB and Management of Wilton Re
Related Party Transaction [Line Items]
Reinsurance recoverables	$ 6,884	$ 7,003
Canada Pension Plan Investment Board \| Affiliated Entity
Related Party Transaction [Line Items]
Ownership percentage	8.40%
Economic interest percentage	17.90%
CPPIB and Management of Wilton Re \| Wilton Re
Related Party Transaction [Line Items]
Ownership percentage by parent	100.00%

Related Party Transactions - KaylaRe (Details) - USD ($) $ in Thousands			3 Months Ended		9 Months Ended
	May 14, 2018	Dec. 15, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	May 13, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party, Consolidated Balance Sheet [Abstract]
Reinsurance balances recoverable			$ 1,975,556		$ 1,975,556				$ 2,021,030
Insurance and reinsurance balances payable			381,114		381,114				236,697
Related Party, Consolidated Statement of Earnings [Abstract]
Management fee income					1,453	$ 6,059
Ceded premium earned			(77,969)	$ (120,188)	(276,962)	(315,287)
Net incurred losses and LAE			153,974	75,712	266,327	163,224
Acquisition costs			$ 54,242	$ 24,281	137,684	75,457
Kayla Re
Related Party Transaction [Line Items]
Initial capital raise		$ 620,000
KaylaRe transactions with Starstone
Related Party, Consolidated Statement of Earnings [Abstract]
Ceded premium earned					(52,651)	(170,552)
Net incurred losses and LAE					31,654	127,578
Acquisition costs					18,774	67,375
Kayla Re
Related Party Transaction [Line Items]
Ownership percentage							48.20%
Carrying value of previously held equity method investment prior to the close of the transaction	$ 320,100							$ 320,130	309,800
Subsidiaries \| KaylaRe transactions with Fitzwilliam
Related Party, Consolidated Statement of Earnings [Abstract]
Net incurred losses and LAE					0	(12,791)
Transactions Under Reinsurance Agreement [Abstract]
Profit Commission					$ 0	11,525
Kayla Re
Related Party Transaction [Line Items]
Shares issued (in shares)	2,007,017
Ordinary Shares \| Kayla Re
Related Party Transaction [Line Items]
Shares issued (in shares)	1,501,778
Ordinary Shares \| Kayla Re \| Hillhouse
Related Party Transaction [Line Items]
Shares issued (in shares)	1,204,353
Ordinary Shares \| Kayla Re \| Trident
Related Party Transaction [Line Items]
Shares issued (in shares)	285,986
Non-voting convertible ordinary Series E Shares (issued and outstanding 2018: 910,010; 2017: 404,771) \| Kayla Re
Related Party Transaction [Line Items]
Shares issued (in shares)	505,239
Non-voting convertible ordinary Series E Shares (issued and outstanding 2018: 910,010; 2017: 404,771) \| Kayla Re \| Hillhouse
Related Party Transaction [Line Items]
Shares issued (in shares)	505,239
Non-voting convertible ordinary Series E Shares (issued and outstanding 2018: 910,010; 2017: 404,771) \| Kayla Re \| Minority Shareholder
Related Party Transaction [Line Items]
Shares issued (in shares)	11,439
Starstone \| Kayla Re
Related Party Transaction [Line Items]
Percentage of business reinsured					35.00%
Fitzwilliam \| Subsidiaries \| Kayla Re
Related Party Transaction [Line Items]
Ceded reinsurance receivables										$ 177,200
Affiliated Entity \| Kayla Re
Transactions Under Reinsurance Agreement [Abstract]
Total investment earnings					$ (770)	$ 29,194
Equity Method Investee \| Kayla Re
Related Party, Consolidated Balance Sheet [Abstract]
Reinsurance balances recoverable									357,355
Prepaid insurance premiums									116,356
Funds held									174,181
Insurance and reinsurance balances payable									232,884
Ceded acquisition costs									$ 36,070

Related Party Transactions - Hillhouse (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Related Party Transaction [Line Items]
Other investments	$ 2,036,430		$ 2,036,430		$ 913,392
Additional subscriptions			784,316	$ 98,203
Net realized and unrealized gains (losses)	$ (57,223)	$ 29,301	$ (254,671)	$ 139,697
Hillhouse Affiliates \| Affiliated Entity
Related Party Transaction [Line Items]
Ownership percentage	9.70%		9.70%
Economic interest percentage	17.10%		17.10%
Kayla Re \| Affiliated Entity
Related Party Transaction [Line Items]
Additional subscriptions			$ 538,100
Hillhouse \| Affiliated Entity
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party			8,500
Hillhouse \| Kayla Re \| Affiliated Entity
Related Party Transaction [Line Items]
Other investments	$ 0		0		456,660
Additional subscriptions			445,500
Subsidiaries \| Hillhouse \| Cavello Bay
Related Party Transaction [Line Items]
Other investments	$ 903,568		$ 903,568		$ 0

Related Party Transactions - Monument (Details) $ in Thousands, € in Millions	3 Months Ended		9 Months Ended		21 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Aug. 29, 2017 USD ($)	Aug. 29, 2017 EUR (€)
Related Party Transaction [Line Items]
Loss on sale of subsidiary	$ 0	$ 6,740	$ 0	$ 16,349
Cumulative CTA adjustment	$ 0	7,440	$ 0	7,440
Laguna \| Disposed of by sale
Related Party Transaction [Line Items]
Loss on sale of subsidiary		6,700		$ 16,300
Cumulative CTA adjustment		$ 6,300
Laguna \| Monument \| Disposed of by sale \| Affiliated Entity
Related Party Transaction [Line Items]
Disposal, consideration							$ 30,800	€ 25.6
Monument
Related Party Transaction [Line Items]
Contributed amount of common and preferred shares					$ 26,600
Ownership percentage	26.60%		26.60%
Carrying value of previously held equity method investment prior to the close of the transaction	$ 35,587		$ 35,587			$ 15,960

Related Party Transactions - Clear Spring (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Jan. 01, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Capitalized amount of investment	$ 56,000
Balances under StarStone quota share:
Reinsurance balances recoverable		$ 1,975,556		$ 1,975,556			$ 2,021,030
Losses and LAE
Losses and LAE		8,535,733	$ 7,615,717	8,535,733	$ 7,615,717	$ 8,608,387	7,398,088	$ 7,641,384	$ 5,987,867
Unearned reinsurance premiums		743,024		743,024			583,197
Funds held		254,029		254,029			175,383
Transactions under StarStone quota share:
Ceded premium earned		(77,969)	(120,188)	(276,962)	(315,287)
Acquisition costs		(54,242)	(24,281)	(137,684)	(75,457)
Transactions under Cavello Bay quota share:
Net incurred losses and LAE		153,974	75,712	266,327	163,224
Clear Spring \| Affiliated Entity
Transactions under Cavello Bay quota share:
Net income statement amounts		$ (1,707)	(1,270)	$ (3,234)	(1,270)
Clear Spring \| Equity Method Investee
Related Party Transaction [Line Items]
Ownership percentage		20.00%		20.00%
Balances under StarStone quota share:
Reinsurance balances recoverable		$ 19,192		$ 19,192			9,053
Prepaid insurance premiums		12,215		12,215			13,747
Ceded payable		15,275		15,275			13,964
Ceded acquisition costs		2,920		2,920			3,186
Starstone \| Clear Spring
Related Party Transaction [Line Items]
Carrying value of previously held equity method investment prior to the close of the transaction		10,565		10,565			10,596
Percentage of business reinsured	33.30%
Starstone \| Clear Spring \| Affiliated Entity
Transactions under StarStone quota share:
Ceded premium earned		(6,926)	(8,393)	(21,564)	(8,393)
Ceded incurred losses and LAE		3,823	2,068	12,429	2,068
Acquisition costs		(981)	(5,540)	(4,892)	(5,540)
Starstone \| Cavello Bay
Related Party Transaction [Line Items]
Percentage of business reinsured	25.00%
Cavello Bay \| Clear Spring
Losses and LAE
Losses and LAE		4,682		4,682			2,231
Unearned reinsurance premiums		3,054		3,054			3,437
Funds held		8,744		8,744			$ 5,095
Cavello Bay \| Clear Spring \| Affiliated Entity
Transactions under StarStone quota share:
Acquisition costs		(721)	(1,198)	(1,275)	(1,198)
Transactions under Cavello Bay quota share:
Premium earned		3,482	2,098	5,391	2,098
Net incurred losses and LAE		$ (2,346)	$ (1,385)	$ (3,107)	$ (1,385)

Related Party Transactions - AmTrust (Details) - Affiliated Entity $ in Millions	Jul. 23, 2018 USD ($)
Evergreen Parent L.P. \| AmTrust Financial Services, Inc.
Related Party Transaction [Line Items]
Ownership percentage	45.00%
Evergreen Parent L.P.
Related Party Transaction [Line Items]
Purchase amount of equity interest	$ 200.0
Capital units ownership percentage	7.40%

Related Party Transactions - Citco (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Related Party Transaction [Line Items]
Indirect investment acquired		$ 784,316	$ 98,203
Other investments		$ 2,036,430		$ 913,392
Trident \| Citco III Limited \| Affiliated Entity
Related Party Transaction [Line Items]
Indirect investment acquired	$ 50,000
Ownership percentage		3.40%
Citco III Limited
Related Party Transaction [Line Items]
Other investments		$ 49,606		$ 0

Commitments and Contingencies (Details) - USD ($)	9 Months Ended
Commitments and Contingencies (Details) - USD ($)	Sep. 30, 2018	Feb. 08, 2018	Dec. 31, 2017
Guarantor Obligations [Line Items]
Funds held by reinsured companies	$ 254,029,000		$ 175,383,000
Asbestos personal injury liabilities
Guarantor Obligations [Line Items]
Indemnity and defense costs	187,900,000		205,700,000
Insurance recoveries receivable	114,800,000		122,300,000
Asbestos personal injury liabilities \| Dana properties
Guarantor Obligations [Line Items]
Indemnity and defense costs	2,100,000		2,200,000
Limited Parental Guarantee
Guarantor Obligations [Line Items]
Parental guarantees	620,000,000		$ 630,700,000
US
Guarantor Obligations [Line Items]
Concentration of credit risk, counterparty credit exposure	787,900,000
Reinsurance Recoverables \| Reinsurer Concentration Risk
Guarantor Obligations [Line Items]
Funds held by reinsured companies	1,037,600,000
Line of Credit \| FAL Facility \| Letters of Credit
Guarantor Obligations [Line Items]
Maximum borrowing capacity	295,000,000	$ 325,000,000
Higher borrowing capacity option		$ 400,000,000
Letters of credit issued	295,000,000
Private equity funds
Guarantor Obligations [Line Items]
Commitments, unfunded	200,000,000
Equity and equity method investments
Guarantor Obligations [Line Items]
Commitments, unfunded	$ 200,000,000

Segment Information - Additional Information (Detail)	9 Months Ended
Segment Information - Additional Information (Detail)	Sep. 30, 2018 Segment
Segment Reporting [Abstract]
Number of segments	3

Segment Information - Summary of Operations by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Gross premiums written	$ 333,278	$ 250,559	$ 1,039,076	$ 786,924
Net premiums written	262,467	136,176	738,834	447,783
Net premiums earned	264,597	148,025	663,628	452,494
Net incurred losses and LAE	(153,974)	(75,712)	(266,327)	(163,224)
Life and Annuity Policy Benefits	(423)	(1,060)	(217)	(5,048)
Acquisition costs	(54,242)	(24,281)	(137,684)	(75,457)
Operating expenses	(79,425)	(70,769)	(233,212)	(208,570)
Underwriting income (loss)	(23,467)	(23,797)	26,188	195
Net investment income	69,430	52,028	202,218	150,184
Net realized and unrealized gains (losses)	(57,223)	29,301	(254,671)	139,697
Fees and commission income	6,950	15,895	23,633	46,476
Other income (expense)	11,543	(3,848)	34,477	19,206
Corporate expenses	(23,128)	(29,556)	(67,213)	(100,713)
Interest income (expense)	(4,640)	(6,410)	(21,573)	(20,851)
Net foreign exchange losses	(1,040)	(4,775)	(1,389)	(15,612)
Loss on sale of subsidiary	0	(6,740)	0	(16,349)
EARNINGS (LOSS) BEFORE INCOME TAXES	(21,575)	22,098	(58,330)	202,233
INCOME (TAXES) BENEFIT	(746)	(1,432)	(4,564)	(3,234)
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	(22,321)	20,666	(62,894)	198,999
NET EARNINGS (LOSS) FROM DISCONTINUED OPERATIONS, NET OF INCOME TAXES	0	3,495	0	(1,005)
NET EARNINGS (LOSS)	(22,321)	24,161	(62,894)	197,994
Net loss (earnings) attributable to noncontrolling interest	11,489	14,832	19,096	(14,135)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	(10,832)	38,993	(43,798)	183,859
Dividends on preferred shares	(5,133)	0	(5,133)	0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	(15,965)	38,993	(48,931)	183,859
Non-life Run-off
Segment Reporting Information [Line Items]
Net incurred losses and LAE	62,778	70,882	205,890	138,041
Atrium
Segment Reporting Information [Line Items]
Net incurred losses and LAE	$ (17,853)	$ (35,273)	$ (51,951)	$ (55,950)
Underwriting Loss Ratio	48.30%	107.60%	48.70%	57.50%
Underwriting Acquisition Expense Ratio	35.70%	36.10%	35.60%	35.60%
Underwriting Other Operating Expense Ratio	10.70%	7.60%	11.50%	12.50%
Underwriting Combined Ratio	94.70%	151.30%	95.80%	105.60%
StarStone
Segment Reporting Information [Line Items]
Net incurred losses and LAE	$ (198,899)	$ (111,321)	$ (420,266)	$ (245,315)
Underwriting Loss Ratio	91.90%	103.40%	79.80%	71.80%
Underwriting Acquisition Expense Ratio	19.00%	10.50%	18.00%	11.60%
Underwriting Other Operating Expense Ratio	17.60%	30.30%	20.20%	29.20%
Underwriting Combined Ratio	128.50%	144.20%	118.00%	112.60%
Operating Segments \| Non-life Run-off
Segment Reporting Information [Line Items]
Gross premiums written	$ 9,912	$ 11,751	$ 16,354	$ 13,956
Net premiums written	4,778	11,467	3,217	13,453
Net premiums earned	10,442	6,415	27,229	9,856
Net incurred losses and LAE	62,778	70,882	205,890	138,041
Life and Annuity Policy Benefits	0	0	0	0
Acquisition costs	160	(1,001)	(4,524)	(455)
Operating expenses	(37,473)	(35,657)	(114,254)	(96,767)
Underwriting income (loss)	35,907	40,639	114,341	50,675
Net investment income	59,247	42,829	168,189	118,130
Net realized and unrealized gains (losses)	(58,506)	25,016	(230,829)	127,130
Fees and commission income	3,708	10,762	13,093	30,302
Other income (expense)	11,423	(4,018)	34,989	18,679
Corporate expenses	(11,433)	(20,326)	(33,453)	(66,468)
Interest income (expense)	(5,951)	(6,664)	(24,562)	(20,991)
Net foreign exchange losses	17	(3,772)	(202)	(6,709)
Loss on sale of subsidiary		0		0
EARNINGS (LOSS) BEFORE INCOME TAXES	34,412	84,466	41,566	250,748
INCOME (TAXES) BENEFIT	(125)	(970)	(227)	(5,609)
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	34,287	83,496	41,339	245,139
NET EARNINGS (LOSS) FROM DISCONTINUED OPERATIONS, NET OF INCOME TAXES		0		0
NET EARNINGS (LOSS)		83,496		245,139
Net loss (earnings) attributable to noncontrolling interest	(1,659)	(3,314)	(4,182)	(13,944)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	32,628		37,157
Dividends on preferred shares	0		0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	32,628	80,182	37,157	231,195
Operating Segments \| Atrium
Segment Reporting Information [Line Items]
Gross premiums written	39,995	36,377	130,997	117,355
Net premiums written	37,141	25,989	113,218	99,235
Net premiums earned	36,977	32,773	106,722	97,373
Net incurred losses and LAE	(17,853)	(35,273)	(51,951)	(55,950)
Life and Annuity Policy Benefits	0	0	0	0
Acquisition costs	(13,215)	(11,818)	(37,996)	(34,647)
Operating expenses	(3,952)	(2,507)	(12,259)	(12,227)
Underwriting income (loss)	1,957	(16,825)	4,516	(5,451)
Net investment income	1,597	847	4,067	2,832
Net realized and unrealized gains (losses)	194	285	(1,889)	1,177
Fees and commission income	3,242	5,911	10,540	17,353
Other income (expense)	7	69	127	188
Corporate expenses	(2,770)	37	(5,083)	(7,404)
Interest income (expense)	0	(23)	0	(559)
Net foreign exchange losses	(262)	(43)	(1,262)	(4,355)
Loss on sale of subsidiary		0		0
EARNINGS (LOSS) BEFORE INCOME TAXES	3,965	(9,742)	11,016	3,781
INCOME (TAXES) BENEFIT	(737)	(554)	(1,756)	(1,278)
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	3,228	(10,296)	9,260	2,503
NET EARNINGS (LOSS) FROM DISCONTINUED OPERATIONS, NET OF INCOME TAXES		0		0
NET EARNINGS (LOSS)		(10,296)		2,503
Net loss (earnings) attributable to noncontrolling interest	(1,266)	4,223	(3,798)	(1,027)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	1,962		5,462
Dividends on preferred shares	0		0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	1,962	(6,073)	5,462	1,476
Operating Segments \| StarStone
Segment Reporting Information [Line Items]
Gross premiums written	282,525	200,007	888,867	651,107
Net premiums written	219,726	97,049	619,528	331,449
Net premiums earned	216,355	107,650	526,802	341,609
Net incurred losses and LAE	(198,899)	(111,321)	(420,266)	(245,315)
Life and Annuity Policy Benefits	0	0	0	0
Acquisition costs	(41,079)	(11,313)	(94,775)	(39,625)
Operating expenses	(38,000)	(32,605)	(106,699)	(99,576)
Underwriting income (loss)	(61,623)	(47,589)	(94,938)	(42,907)
Net investment income	9,504	7,592	25,950	20,230
Net realized and unrealized gains (losses)	989	5,045	(15,150)	18,953
Fees and commission income	0	0	0	1,166
Other income (expense)	117	91	(432)	170
Corporate expenses	0	0	0	0
Interest income (expense)	0	(382)	(547)	(1,648)
Net foreign exchange losses	(585)	1,145	(1,063)	(1,563)
Loss on sale of subsidiary		0		0
EARNINGS (LOSS) BEFORE INCOME TAXES	(51,598)	(34,098)	(86,180)	(5,599)
INCOME (TAXES) BENEFIT	118	78	(2,568)	3,648
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	(51,480)	(34,020)	(88,748)	(1,951)
NET EARNINGS (LOSS) FROM DISCONTINUED OPERATIONS, NET OF INCOME TAXES		0		0
NET EARNINGS (LOSS)		(34,020)		(1,951)
Net loss (earnings) attributable to noncontrolling interest	14,414	13,923	27,076	836
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	(37,066)		(61,672)
Dividends on preferred shares	0		0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	(37,066)	(20,097)	(61,672)	(1,115)
Other
Segment Reporting Information [Line Items]
Gross premiums written	846	2,424	2,858	4,506
Net premiums written	822	1,671	2,871	3,646
Net premiums earned	823	1,187	2,875	3,656
Net incurred losses and LAE	0	0	0	0
Life and Annuity Policy Benefits	(423)	(1,060)	(217)	(5,048)
Acquisition costs	(108)	(149)	(389)	(730)
Operating expenses	0	0	0	0
Underwriting income (loss)	292	(22)	2,269	(2,122)
Net investment income	(918)	760	4,012	8,992
Net realized and unrealized gains (losses)	100	(1,045)	(6,803)	(7,563)
Fees and commission income	0	(778)	0	(2,345)
Other income (expense)	(4)	10	(207)	169
Corporate expenses	(8,925)	(9,267)	(28,677)	(26,841)
Interest income (expense)	1,311	659	3,536	2,347
Net foreign exchange losses	(210)	(2,105)	1,138	(2,985)
Loss on sale of subsidiary		(6,740)		(16,349)
EARNINGS (LOSS) BEFORE INCOME TAXES	(8,354)	(18,528)	(24,732)	(46,697)
INCOME (TAXES) BENEFIT	(2)	14	(13)	5
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS	(8,356)	(18,514)	(24,745)	(46,692)
NET EARNINGS (LOSS) FROM DISCONTINUED OPERATIONS, NET OF INCOME TAXES		3,495		(1,005)
NET EARNINGS (LOSS)		(15,019)		(47,697)
Net loss (earnings) attributable to noncontrolling interest	0	0	0	0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	(8,356)		(24,745)
Dividends on preferred shares	(5,133)		(5,133)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	$ (13,489)	$ (15,019)	$ (29,878)	$ (47,697)

Segment Information - Summary of Company's Assets by Segment (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 15,121,228	$ 13,606,422
Operating Segments \| Non-life Run-off
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	11,907,196	10,368,105
Operating Segments \| Atrium
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	598,072	556,637
Operating Segments \| StarStone
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	3,199,238	3,128,725
Other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ (583,278)	$ (447,045)

Investments - Credit Ratings of Fixed Maturity and Short-Term Investments, Trading (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 6,852,793
Fair Value	6,708,424
Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 402,379
Marketable Securities \| Portfolio Concentration Risk \| Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	100.00%
Trading and Available for Sale Securities \| Credit Rating Concentration Risk \| Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	6.00%
AAA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,605,553
AAA Rated \| Trading and Available for Sale Securities \| Credit Rating Concentration Risk \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	23.90%
AA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,140,493
AA Rated \| Trading and Available for Sale Securities \| Credit Rating Concentration Risk \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	17.00%
A Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 2,263,287
A Rated \| Trading and Available for Sale Securities \| Credit Rating Concentration Risk \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	33.80%
BBB Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,276,705
BBB Rated \| Trading and Available for Sale Securities \| Credit Rating Concentration Risk \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	19.00%
Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 20,007
Not Rated \| Trading and Available for Sale Securities \| Credit Rating Concentration Risk
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	0.30%
U.S. government and agency
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 502,168
Fair Value	493,778
U.S. government and agency \| Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 0
U.S. government and agency \| Marketable Securities \| Portfolio Concentration Risk \| Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	7.40%
U.S. government and agency \| AAA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 489,939
U.S. government and agency \| AA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	3,839
U.S. government and agency \| A Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
U.S. government and agency \| BBB Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
U.S. government and agency \| Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
Non-U.S. government
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	1,109,697
Fair Value	1,093,768
Non-U.S. government \| Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 25,615
Non-U.S. government \| Marketable Securities \| Portfolio Concentration Risk \| Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	16.30%
Non-U.S. government \| AAA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 340,583
Non-U.S. government \| AA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	541,087
Non-U.S. government \| A Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	65,286
Non-U.S. government \| BBB Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	121,197
Non-U.S. government \| Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
Corporate
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	3,893,368
Fair Value	3,786,537
Corporate \| Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 180,730
Corporate \| Marketable Securities \| Portfolio Concentration Risk \| Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	56.40%
Corporate \| AAA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 154,961
Corporate \| AA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	445,858
Corporate \| A Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	1,986,880
Corporate \| BBB Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	1,016,401
Corporate \| Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	1,707
Municipal
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	81,703
Fair Value	79,966
Municipal \| Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 0
Municipal \| Marketable Securities \| Portfolio Concentration Risk \| Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	1.20%
Municipal \| AAA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 8,739
Municipal \| AA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	53,094
Municipal \| A Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	14,277
Municipal \| BBB Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	3,856
Municipal \| Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
Residential mortgage-backed
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	274,848
Fair Value	275,500
Residential mortgage-backed \| Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 92,180
Residential mortgage-backed \| Marketable Securities \| Portfolio Concentration Risk \| Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	4.10%
Residential mortgage-backed \| AAA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 163,190
Residential mortgage-backed \| AA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	2,526
Residential mortgage-backed \| A Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	11,331
Residential mortgage-backed \| BBB Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	1,540
Residential mortgage-backed \| Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	4,733
Commercial mortgage-backed
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	423,471
Fair Value	411,575
Commercial mortgage-backed \| Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 9,936
Commercial mortgage-backed \| Marketable Securities \| Portfolio Concentration Risk \| Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	6.10%
Commercial mortgage-backed \| AAA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 210,902
Commercial mortgage-backed \| AA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	47,118
Commercial mortgage-backed \| A Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	70,164
Commercial mortgage-backed \| BBB Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	60,296
Commercial mortgage-backed \| Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	13,159
Asset-backed
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	567,538
Fair Value	567,300
Asset-backed \| Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 93,918
Asset-backed \| Marketable Securities \| Portfolio Concentration Risk \| Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
% of Total Investments	8.50%
Asset-backed \| AAA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 237,239
Asset-backed \| AA Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	46,971
Asset-backed \| A Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	115,349
Asset-backed \| BBB Rated \| Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	73,415
Asset-backed \| Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 408

Reinsurance Balances Recoverable Reinsurance Balances Recoverable - Top Ten Reinsurers (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018 USD ($) reinsurer	Dec. 31, 2017 USD ($) reinsurer
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	$ 1,975,556	$ 2,021,030
Top ten reinsurers \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	1,435,855	1,516,736
Top 10 Total \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	$ 1,116,423	$ 829,164
Number of external reinsurers \| reinsurer	7	6
Top Ten Reinsurers, Four Non-Rated Reinsurers \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	$ 319,432	$ 687,572
Number of external reinsurers \| reinsurer	3	4
Reinsurance balances recoverable \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	$ 1,975,556	$ 2,021,030
Concentration risk percentage	100.00%	100.00%
Reinsurance balances recoverable \| Top ten reinsurers \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	$ 1,435,855
Concentration risk percentage	72.70%	75.00%
Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	$ 518,365	$ 483,689
Concentration risk percentage	26.20%	24.00%
Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	$ 21,336	$ 20,605
Concentration risk percentage	1.10%	1.00%
Non-life Run-off
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	$ 1,520,308
Non-life Run-off \| Reinsurance balances recoverable \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	1,520,308
Non-life Run-off \| Reinsurance balances recoverable \| Top ten reinsurers \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	1,167,500
Non-life Run-off \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	335,939
Non-life Run-off \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	16,869
Atrium
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	43,574
Atrium \| Reinsurance balances recoverable \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	43,574
Atrium \| Reinsurance balances recoverable \| Top ten reinsurers \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	28,669
Atrium \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	14,232
Atrium \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	673
StarStone
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	411,674
StarStone \| Reinsurance balances recoverable \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	411,674
StarStone \| Reinsurance balances recoverable \| Top ten reinsurers \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	239,686
StarStone \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	168,194
StarStone \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	3,794
Equity Method Investee \| Hannover Ruck \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	327,287	$ 320,047
Equity Method Investee \| Lloyds of London \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable	$ 303,598	193,838
Operating Segments \| Non-life Run-off
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		1,505,738
Operating Segments \| Non-life Run-off \| Reinsurance balances recoverable \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		1,505,738
Operating Segments \| Non-life Run-off \| Reinsurance balances recoverable \| Top ten reinsurers \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		1,166,057
Operating Segments \| Non-life Run-off \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		322,722
Operating Segments \| Non-life Run-off \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		16,959
Operating Segments \| Atrium
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		40,080
Operating Segments \| Atrium \| Reinsurance balances recoverable \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		40,080
Operating Segments \| Atrium \| Reinsurance balances recoverable \| Top ten reinsurers \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		22,422
Operating Segments \| Atrium \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		16,631
Operating Segments \| Atrium \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		1,027
Operating Segments \| StarStone
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		475,196
Operating Segments \| StarStone \| Reinsurance balances recoverable \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		475,196
Operating Segments \| StarStone \| Reinsurance balances recoverable \| Top ten reinsurers \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		328,257
Operating Segments \| StarStone \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		144,336
Operating Segments \| StarStone \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		2,603
Other
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		16
Other \| Reinsurance balances recoverable \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		16
Other \| Reinsurance balances recoverable \| Top ten reinsurers \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		0
Other \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		0
Other \| Reinsurance balances recoverable \| Other reinsurers $1 million \| Reinsurer Concentration Risk
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable		$ 16