Endurance Specialty (ENH) 10-K 1 Mar 17 2016 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 27, 2017	Jun. 30, 2016
Document and Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Entity Registrant Name	Endurance Specialty Holdings Ltd.
Entity Central Index Key	1,179,755
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Entity Common Stock, Shares Outstanding		67,616,222
Entity Public Float			$ 3,747,152,576

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Fixed maturity investments, trading at fair value (amortized cost: $2,727,271 and $1,611,079 at December 31, 2016 and 2015, respectively)	$ 2,740,055	$ 1,587,160
Fixed maturity investments, available for sale at fair value (amortized cost: $3,538,227 and $4,361,997 at December 31, 2016 and 2015, respectively)	3,572,766	4,359,019
Short-term investments, trading at fair value (amortized cost: $330,305 and $394,096 at December 31, 2016 and 2015, respectively)	330,199	394,111
Short-term investments, available for sale at fair value (amortized cost: $78,506 and $25,657 at December 31, 2016 and 2015, respectively)	78,505	25,685
Equity securities, trading at fair value (cost: $16,094 and $15,290 at December 31, 2016 and 2015, respectively)	16,056	15,229
Equity securities, available for sale at fair value (cost: $461,684 and $542,429 at December 31, 2016 and 2015, respectively)	485,085	513,585
Other investments	588,308	872,617
Total investments	7,810,974	7,767,406
Cash and cash equivalents	1,149,541	1,177,750
Premiums receivable, net	1,657,752	1,376,328
Insurance and reinsurance balances receivable	110,183	102,403
Deferred acquisition costs	276,639	255,501
Prepaid reinsurance premiums	711,695	498,574
Reinsurance recoverable on unpaid losses	1,213,129	907,944
Reinsurance recoverable on paid losses	273,789	288,026
Accrued investment income	35,853	30,213
Goodwill and intangible assets	468,374	553,960
Deferred tax asset	71,802	64,164
Net receivable on sales of investments	54,620	31,873
Other assets	288,510	187,383
Total assets	14,122,861	13,241,525
LIABILITIES
Reserve for losses and loss expenses	4,905,138	4,510,415
Reserve for unearned premiums	1,994,676	1,789,148
Deposit liabilities	14,013	13,674
Reinsurance balances payable	784,162	661,213
Debt	705,292	717,650
Net payable on purchases of investments	181,337	63,442
Deferred tax liability	13,074	17,315
Other liabilities	383,036	344,596
Total liabilities	8,980,728	8,117,453
Commitments and contingent liabilities
SHAREHOLDERS' EQUITY
Preferred shares, total liquidation preference $230,000 (2015 - $460,000)	9	9,209
Common shares, ordinary - 67,627,901 issued and outstanding (2015 - 66,797,991)	67,628	66,798
Additional paid-in capital	1,961,917	2,145,836
Accumulated other comprehensive loss	(58,749)	(46,634)
Retained earnings	2,911,634	2,681,053
Total shareholders' equity available to Endurance Holdings	4,882,439	4,856,262
Non-controlling interests	259,694	267,810
Total shareholders' equity	5,142,133	5,124,072
Total liabilities and shareholders' equity	$ 14,122,861	$ 13,241,525

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Investments [Abstract]
Fixed maturity investments, trading, amortized cost	$ 2,727,271	$ 1,611,079
Fixed maturity investments, available for sale, amortized cost	3,538,227	4,361,997
Short-term investments, trading, amortized cost	330,305	394,096
Short-term investments, available for sale, amortized cost	78,506	25,657
Equity securities, trading, cost	16,094	15,290
Equity securities, available for sale, cost	461,684	542,429
Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract]
Preferred shares, total liquidation preference	$ 230,000	$ 460,000
Common shares, ordinary, number of shares issued	67,627,901	66,797,991
Common shares, ordinary, number of shares outstanding	67,627,901	66,797,991

Consolidated Statements Of Inco

Consolidated Statements Of Income And Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues
Gross premiums written	$ 4,202,170	$ 3,320,861	$ 2,894,076
Ceded premiums written	(1,832,235)	(1,370,391)	(959,870)
Net premiums written	2,369,935	1,950,470	1,934,206
Change in unearned premiums	(6,275)	27,983	(70,228)
Net premiums earned	2,363,660	1,978,453	1,863,978
Net investment income	176,590	113,826	131,543
Net realized and unrealized (losses) gains	(12,419)	12,660	14,283
Net impairment losses recognized in earnings	(10,769)	(3,715)	(625)
Other underwriting loss	(909)	(3,694)	(5,786)
Total revenues	2,516,153	2,097,530	2,003,393
Expenses
Net losses and loss expenses	1,321,052	917,108	970,162
Acquisition expenses	460,483	347,885	319,513
General and administrative expenses	248,146	259,791	247,387
Corporate expenses	51,706	114,429	66,200
Amortization of intangibles	84,624	30,620	6,484
Net foreign exchange (gains) losses	(74,684)	26,964	3,839
Interest expense	43,860	41,260	40,968
Total expenses	2,135,187	1,738,057	1,654,553
Income before income taxes	380,966	359,473	348,840
Income tax benefit (expense)	181	(4,362)	(390)
Net income	381,147	355,111	348,450
Net income attributable to non-controlling interests	(24,130)	(11,016)	0
Net income available to Endurance Holdings	357,017	344,095	348,450
Preferred dividends	(23,799)	(32,750)	(32,750)
Net income available to Endurance Holdings' common and participating common shareholders	333,218	311,345	315,700
Comprehensive income
Net income	381,147	355,111	348,450
Other comprehensive (loss) income
Net unrealized holding gains (losses) on investments arising during the period (net of other-than-temporary impairment losses recognized in other comprehensive (loss) income, reclassification adjustment and applicable deferred income tax (expense) benefit in 2016 - ($8,804); 2015 - $5,890; 2014 - ($4,121))	74,121	(98,738)	40,150
Foreign currency translation adjustments	(86,324)	(24,690)	(26,264)
Reclassification adjustment for net losses on derivatives designated as cash flow hedge included in net income	88	88	89
Other comprehensive (loss) income	(12,115)	(123,340)	13,975
Comprehensive income	369,032	231,771	362,425
Comprehensive income attributable to non-controlling interests	(24,130)	(11,016)	0
Comprehensive income attributable to Endurance Holdings common and participating common shareholders	$ 344,902	$ 220,755	$ 362,425
Per share data
Basic earnings per common share	$ 4.94	$ 5.74	$ 7.07
Diluted earnings per common share	$ 4.93	$ 5.73	$ 7.06

Consolidated Statements Of Inc5

Consolidated Statements Of Income And Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Deferred income taxes on net unrealized holding gains (losses) on investments	$ (8,804)	$ 5,890	$ (4,121)

Consolidated Statements Of Chan

Consolidated Statements Of Changes In Shareholders' Equity - USD ($) $ in Thousands	Total	Preferred shares	Common shares	Additional paid-in capital	Accumulated other comprehensive (loss) income	Cumulative foreign currency translation adjustments	Unrealized holding gains (losses) on investments, net of deferred taxes	Accumulated derivative loss on cash flow hedging instruments	Retained earnings
Balance, beginning of year at Dec. 31, 2013		$ 17,200	$ 44,369	$ 569,116		$ 18,636	$ 45,950	$ (1,855)	$ 2,193,133
Issuance of Series C, non-cumulative preferred shares		0		0
Redemption of Series A and B, non-cumulative preferred shares		0		0
Issuance of common shares, net of forfeitures			396	2,143
Public offering and registration costs				0
Settlement of equity awards				(4,039)
Stock-based compensation expense				31,006
Foreign currency translation adjustments	$ (26,264)					(26,264)
Net unrealized holding gains (losses) arising during the year, net of other-than-temporary impairment losses and reclassification adjustment	40,150						40,150
Net change from current period hedging transactions, net of reclassification adjustment								89
Net income	348,450								348,450
Net income attributable to non-controlling interests	0								0
Dividends on preferred shares	(32,750)								(32,750)
Dividends on common shares									(60,548)
Balance, end of year at Dec. 31, 2014	3,185,182	17,200	44,765	598,226	$ 76,706	(7,628)	86,100	(1,766)	2,448,285
Non-controlling interests	0
Total shareholders' equity	3,185,182
Issuance of Series C, non-cumulative preferred shares		9		222,954
Redemption of Series A and B, non-cumulative preferred shares		(8,000)		(192,000)
Issuance of common shares, net of forfeitures			22,033	1,476,615
Public offering and registration costs				(936)
Settlement of equity awards				(14,535)
Stock-based compensation expense				55,512
Foreign currency translation adjustments	(24,690)					(24,690)
Net unrealized holding gains (losses) arising during the year, net of other-than-temporary impairment losses and reclassification adjustment	(98,738)						(98,738)
Net change from current period hedging transactions, net of reclassification adjustment								88
Net income	355,111								355,111
Net income attributable to non-controlling interests	(11,016)								(11,016)
Dividends on preferred shares	(32,750)								(32,750)
Dividends on common shares									(78,577)
Balance, end of year at Dec. 31, 2015	4,856,262	9,209	66,798	2,145,836	(46,634)	(32,318)	(12,638)	(1,678)	2,681,053
Non-controlling interests	258,529
Net income attributable to non-controlling interests	(11,016)
Balance, end of year at Dec. 31, 2015	4,856,262	9,209	66,798	2,145,836	(46,634)	(32,318)	(12,638)	(1,678)	2,681,053
Non-controlling interests	267,810
Total shareholders' equity	5,124,072
Issuance of Series C, non-cumulative preferred shares		0		0
Redemption of Series A and B, non-cumulative preferred shares		(9,200)		(219,767)
Issuance of common shares, net of forfeitures			830	11,135
Public offering and registration costs				0
Settlement of equity awards				(11,732)
Stock-based compensation expense				36,445
Foreign currency translation adjustments	(86,324)					(86,324)
Net unrealized holding gains (losses) arising during the year, net of other-than-temporary impairment losses and reclassification adjustment	74,121						74,121
Net change from current period hedging transactions, net of reclassification adjustment								88
Net income	381,147								381,147
Net income attributable to non-controlling interests	(24,130)								(24,130)
Dividends on preferred shares	(23,799)								(23,799)
Dividends on common shares									(102,637)
Balance, end of year at Dec. 31, 2016	4,882,439	$ 9	$ 67,628	$ 1,961,917	$ (58,749)	$ (118,642)	$ 61,483	$ (1,590)	$ 2,911,634
Non-controlling interests	259,694
Total shareholders' equity	$ 5,142,133

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows provided by operating activities:
Net income	$ 381,147	$ 355,111	$ 348,450
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of net premium on investments	33,285	45,317	45,757
Amortization of other intangibles and depreciation	105,026	51,457	27,234
Net realized and unrealized losses (gains)	12,419	(12,660)	(14,283)
Net impairment losses recognized in earnings	10,769	3,715	625
Deferred taxes	(19,709)	(2,727)	(1,414)
Stock-based compensation expense	36,445	55,512	31,006
Equity in earnings of other investments	(12,442)	13,553	(19,609)
Premiums receivable, net	(281,424)	(153,735)	(214,252)
Insurance and reinsurance balances receivable	(7,780)	33,729	5,508
Deferred acquisition costs	(21,138)	(48,133)	(21,341)
Prepaid reinsurance premiums	(213,121)	(74,944)	(167,731)
Reinsurance recoverable on unpaid losses	(305,185)	(197,097)	(77,040)
Reinsurance recoverable on paid losses	14,237	(61,748)	(54,071)
Accrued investment income	(5,640)	5,840	(3,079)
Other assets	(6,855)	(25,683)	(17,132)
Reserve for losses and loss expenses	394,723	(57,375)	(155,400)
Reserve for unearned premiums	205,528	36,036	235,668
Deposit liabilities	339	(1,462)	(4,322)
Reinsurance balances payable	122,949	204,557	194,650
Other liabilities	(28,081)	76,194	127,037
Net cash flows provided by operating activities	415,492	245,457	266,261
Cash flows (used in) provided by investing activities
Proceeds from sales and maturities of trading investments	3,115,204	626,914	0
Proceeds from sales and maturities of available for sale investments	3,477,688	5,725,794	4,145,940
Proceeds from the redemption of other investments	355,325	188,060	154,655
Purchases of trading investments	(4,091,588)	(1,080,478)	0
Purchases of available for sale investments	(2,752,599)	(5,421,949)	(4,449,225)
Purchases of other investments	(58,222)	(221,457)	(59,023)
Net (purchases) settlements of other assets	(47,450)	21,273	11,665
Purchases of fixed assets	(17,568)	(26,988)	(40,932)
Net cash (paid for) received from subsidiary acquisition	(12)	675,624	39
Net cash flows (used in) provided by investing activities	(19,222)	486,793	(236,881)
Cash flows used in financing activities
Issuance of common shares	10,076	24,823	2,305
Issuance of Series C, non-cumulative preferred shares	0	222,963	0
Redemption of Series A and B, non-cumulative preferred shares	(230,000)	(200,000)	0
Settlement of equity awards	(11,732)	(14,535)	(4,039)
Net distributions to non-controlling interests	(32,246)	(1,739)	0
Offering and registration costs paid	(319)	(617)	0
Proceeds from issuance of repurchase agreements	120,990	0	0
Repayment of repurchase agreements	(120,990)	0	0
Bridge facility costs paid	0	0	(4,750)
Proceeds from issuance of debt	537	5,008	706
Repayments of debt	(13,683)	(199,454)	(686)
Dividends on preferred shares	(23,799)	(32,750)	(32,750)
Dividends on common shares	(102,417)	(78,473)	(60,524)
Net cash flows used in financing activities	(403,583)	(274,774)	(99,738)
Effect of exchange rate changes on cash and cash equivalents	(20,896)	(25,198)	(30,021)
Net (decrease) increase in cash and cash equivalents	(28,209)	432,278	(100,379)
Cash and cash equivalents, beginning of year	1,177,750	745,472	845,851
Cash and cash equivalents, end of year	$ 1,149,541	$ 1,177,750	$ 745,472

Organization

Organization	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	1. Organization Endurance Specialty Holdings Ltd. ("Endurance Holdings", together with its subsidiaries, the "Company") was organized as a Bermuda holding company on June 27, 2002. On July 31, 2015, the Company acquired all of the outstanding common shares of Montpelier Re Holding Ltd. ("Montpelier"), a Bermuda based provider of global property and casualty reinsurance and insurance products. As part of the acquisition, the Company acquired Montpelier's Lloyd's of London ("Lloyd's") operations, including Syndicate 5151 ("Syndicate 5151") and its managing agent, Endurance at Lloyd's Limited ("Endurance at Lloyd's"). Also as part of the acquisition, the Company acquired Montpelier's collateralized reinsurance and third party asset management operations, operating under the name "Blue Capital", which includes Blue Capital Management Ltd. ("BCML"), a wholly-owned subsidiary that provides investment and insurance management services to the Blue Capital vehicles primarily through business written in Blue Water Re Ltd. ("Blue Water Re") and Blue Water Re II Ltd. ("Blue Water Re II"), wholly-owned special purpose insurers. See Note 4, Investments, for additional information with respect to the Blue Capital entities. The Company's Consolidated Statements of Income and Comprehensive Income for the year ended December 31, 2015 include the results of operations of Montpelier from August 1, 2015. For additional information on the acquisition of Montpelier, see Note 3, Acquisition of Montpelier. On October 5, 2016, the Company entered into an agreement and plan of merger (the "Merger Agreement") for the acquisition of 100% of the outstanding ordinary shares of the Company by SOMPO for $93.00 per share in cash (the "Merger"). The Merger has been approved by each company's Board of Directors and the Company's ordinary and preferred shareholders at a special general meeting. The Merger is expected to close as soon as practicable following the satisfaction of customary closing conditions including, but not limited to, regulatory approvals. There can be no assurance that the Merger will occur. Under the terms of the Merger Agreement, the aggregate consideration for the Merger will be approximately $6,304.0 million in cash. The purchase will be financed by SOMPO from existing sources of liquidity and supplementary facilities. If the Merger is terminated under certain circumstances, the Company is obligated to pay SOMPO a cash termination fee of $204.9 million together with SOMPO's expenses related to the Merger up to $15.8 million . The Company is contractually obligated to pay investment banking fees upon the closing of the Merger. Endurance Holdings writes specialty lines of insurance and reinsurance on a global basis through its wholly-owned operating subsidiaries: Operating Subsidiaries Domicile Endurance Specialty Insurance Ltd. ("Endurance Bermuda") Bermuda Blue Capital Management Ltd., manager of Blue Water Re Ltd. and Blue Water Re II Ltd. Bermuda Endurance Worldwide Insurance Limited ("Endurance U.K.") England Endurance at Lloyd's, managing agent for Lloyd's Syndicate 5151 England Endurance Assurance Corporation ("Endurance Assurance", formerly Endurance Reinsurance Corporation of America) Delaware Endurance American Insurance Company ("Endurance American") Delaware Endurance American Specialty Insurance Company ("Endurance American Specialty") Delaware Endurance Risk Solutions Assurance Co. ("Endurance Risk Solutions") Delaware American Agri-Business Insurance Company ("American Agri-Business"), managed by ARMtech Insurance Services, Inc. (together with American Agri-Business, "ARMtech") Texas In addition, as part of the Blue Capital operations Endurance Holdings and Endurance Bermuda together own 33.3% of Blue Capital Reinsurance Holdings Ltd. ("BCRH") and Endurance Bermuda owns 25.2% of Blue Capital Global Reinsurance Fund Limited ("BCGR"). BCRH is a Bermuda-based exempted limited liability holding company managed by BCML that provides fully-collateralized property catastrophe reinsurance and invests in various insurance-linked securities through its wholly-owned Bermuda-based subsidiaries, Blue Capital Re. Ltd. ("Blue Capital Re") and Blue Capital Re ILS Ltd. ("Blue Capital Re ILS"). BCRH's shares are listed on the New York Stock Exchange and the Bermuda Stock Exchange. BCGR is a closed-ended mutual fund incorporated in Bermuda and managed by BCML that serves as the feeder fund for the Blue Capital Global Reinsurance SA-1 cell (the "BCGR Cell"). BCGR's shares are listed on the Specialist Fund Market of the London Stock Exchange and on the Bermuda Stock Exchange.

Summary Of Significant Accounti

Summary Of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary Of Significant Accounting Policies	2. Significant accounting policies The consolidated financial statements have been prepared on the basis of accounting principles generally accepted in the United States ("U.S. GAAP") and include the accounts of Endurance Holdings and its wholly-owned subsidiaries, and BCRH and the BCGR Cell. All intercompany transactions and balances have been eliminated in consolidation. The following are significant accounting and reporting policies adopted by the Company: (a) Premiums and related expenses The Company's insurance premiums are earned pro rata over the term of the applicable risk period specified in the insurance policy. The Company's insurance policies cover losses occurring or claims made during the term of the policy. Generally, the Company receives a fixed premium which is identified in the policy and is recorded on the inception date of the contract or when premiums are determinable and earned evenly over the policy term. This premium will only adjust if the underlying insured values adjust. Accordingly, the Company monitors the underlying insured values and records additional or return premiums in the period in which amounts are reasonably determinable. The Company's reinsurance premiums are earned in proportion to the amount of reinsurance protection provided over the applicable risk period established in the reinsurance contract. Reinsurance contracts written on a losses occurring basis cover losses which occur during the term of the reinsurance contract, typically 12 months. Accordingly, the Company earns the premium on a losses occurring reinsurance contract evenly over the reinsurance contract term. Reinsurance contracts written on a policies attaching basis cover losses from the underlying insurance policies incepting during the terms of the reinsurance contracts. Losses under a policies attaching reinsurance contract may occur after the end date of the reinsurance contract, so long as they are losses from policies that began during the reinsurance contract period. The Company typically earns the premiums for policies attaching reinsurance contracts over a 24 -month period in proportion to the amount of reinsurance protection provided to reflect the extension of the risk period past the term of the contract and the varying levels of reinsurance protection provided during the reinsurance contract period. In addition to the applicable risk period, the Company's estimate of its reinsurance premiums written is based on the type of reinsurance contracts underwritten. For excess of loss reinsurance contracts, the deposit premium, as defined in the contract, is generally considered to be the best estimate of the reinsurance contract's written premium at inception. The Company earns reinstatement premiums upon the occurrence of a loss under the reinsurance contract. Reinstatement premiums are calculated in accordance with the contract terms based upon the ultimate loss estimate associated with each contract. For proportional reinsurance contracts, the Company estimates premium, commissions and related expenses based on broker and ceding company estimates and also utilizes judgment in establishing proportional reinsurance contract estimates. Premiums on the Company's excess of loss and proportional reinsurance contracts are estimated at the time the business is underwritten. Accordingly, this is the amount the Company records as written premium in the period the reinsurance contract is underwritten. As actual premiums are reported by the ceding companies, management evaluates the appropriateness of the original premium estimates and any adjustments to these estimates are recorded in the period in which they become known. Premiums receivable are recorded at amounts due less any allowance for estimated uncollectible premiums receivable. At December 31, 2016 , the Company had an allowance for estimated uncollectible premiums receivable of $6.2 million ( 2015 - $7.4 million ). Acquisition expenses are costs that vary with and are directly related to the successful production of new and renewal business, and consist principally of commissions and brokerage expenses. Acquisition and general and administrative expenses are shown net of commissions, other fees and expense allowances associated with and earned on ceded business. These costs are deferred and amortized over the periods in which the related premiums are earned. Deferred acquisition costs are limited to their estimated realizable value based on the related unearned premiums. Anticipated net investment income is considered in determining the recoverability of deferred acquisition costs. 2. Significant accounting policies, cont'd. (b) Reserve for losses and loss expenses The Company’s reserve for losses and loss expenses includes case reserves and reserves for losses incurred but not reported (referred to as "IBNR reserves"). Case reserves are established for losses that have been reported, but not yet paid. IBNR reserves represent a provision for claims that have been incurred but not yet reported to the Company, as well as future loss development on losses already reported, in excess of the case reserves. Case reserves and IBNR reserves are established by management based on reports from reinsurance intermediaries, ceding companies and insureds, and consultations with independent legal counsel. In addition, reserves for IBNR losses and loss expenses are established by management based on reported losses and loss expenses, and actuarially determined estimates of ultimate losses and loss expenses. The Company uses a variety of actuarial methods to estimate the ultimate losses and loss expenses incurred by the Company. One actuarial method used by the Company to estimate reserves for losses and loss expenses is the expected loss ratio approach, which is based on expected results independent of current loss reporting activity. This approach is typically used for immature loss periods (i.e., the current accident year). Another actuarial method used by the Company to estimate reserves for losses and loss expenses is known as the Bornhuetter-Ferguson method. The Bornhuetter-Ferguson method uses an initial loss estimate (expected loss technique) for each accident year by business line and type of contract. Under this method, IBNR is set equal to the initial loss estimate multiplied by the expected percent of loss yet to be reported at each valuation date. In a given quarter, if reported losses are less than expected, then the difference would result in a decrease in estimated ultimate losses. If losses are greater than expected, then the difference would result in an increase in estimated ultimate losses. A third actuarial method used by the Company to estimate reserves for losses and loss expenses is known as the loss development method. The loss development method extrapolates the current value of reported losses to ultimate expected losses by using selected reporting patterns of losses over time. The selected reporting patterns are based on historical information (organized into loss development triangles) and are adjusted to reflect the changing characteristics of the book of business written by the Company. Management uses these multiple actuarial methods, supplemented with professional judgment, to establish the best estimate of reserves for losses and loss expenses. The Company's loss and loss expense reserves are reviewed regularly, and adjustments, if any, are reflected in earnings in the period in which they become known. The establishment of new loss and loss expense reserves or the adjustment of previously recorded loss and loss expense reserves could result in significant positive or negative changes to the Company's financial condition for any particular period. While management believes the Company's estimate of loss and loss expense reserves is reasonable, the ultimate loss experience may not be reliably predicted, and it is possible losses and loss expenses may be materially different than the total reserve for losses and loss expenses recorded by the Company. (c) Reinsurance Reinsurance recoverable on paid and unpaid losses represent estimates of losses and loss expenses that will be recovered from reinsurers. Amounts recoverable from reinsurers are estimated in a manner consistent with the provisions of the reinsurance agreements and consistent with the establishment of the Company's reserve for losses and loss expenses. Ceding commissions earned on ceded business are classified as an offset to acquisition and general and administrative expenses. (d) Investments The Company currently classifies its fixed maturity investments, short-term investments and equity securities as trading or available for sale. Trading securities are carried at estimated fair value, with related net realized and unrealized gains or losses included in earnings. The Company acquired a portfolio of investments classified as trading from Montpelier. Available for sale securities are carried at estimated fair value, with related net unrealized gains or losses excluded from earnings and included in shareholders' equity as a component of accumulated other comprehensive loss. Investment transactions are recorded on a trade date basis. The Company determines the fair value of its trading and available for sale investments in accordance with current accounting guidance, which defines fair value and establishes a fair value hierarchy based on inputs to the various valuation techniques used for each fair value measurement. The use of valuation techniques for any given investment requires a significant amount of judgment and consideration of factors specific to the underlying investment. Fair value measurements determined by the Company seek to maximize observable inputs and minimize the use of unobservable inputs. 2. Significant accounting policies, cont'd. (d) Investments, cont'd. Current accounting guidance establishes three levels as follows: Level 1: Unadjusted quoted prices in active markets for identical assets or liabilities. Level 2: Quoted prices for similar assets in markets that are active, quoted prices for identical or similar assets in markets that are not active or inputs that are observable either directly or indirectly. Level 2 inputs include quoted prices for similar assets or liabilities other than quoted prices in Level 1; quoted prices in markets that are not active; or other inputs that are observable or can be derived principally from or corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3: Unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities. Unobservable inputs reflect the Company's own views about the assumptions that market participants would use in pricing the asset or liability. Level 3 assets and liabilities include financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation. The Company determines the estimated fair value of each individual security utilizing the highest level inputs available. If the Company has the intent to sell a fixed maturity or short-term security classified as available for sale in an unrealized loss position or it is more likely than not that the Company will be required to sell the available for sale security, the Company deems the security to be other-than-temporarily impaired and writes down the carrying value of the security to fair value, thereby establishing a new cost basis. The amount of the write-down is recognized in earnings as an other-than-temporary impairment ("OTTI") loss. For fixed maturity and short-term investments classified as available for sale in an unrealized loss position for which a decision to sell has not been made and it is not more likely than not that the Company will be required to sell the security, the Company performs additional reviews to determine whether the investment will recover its amortized cost. If the amortized cost of the Company's fixed maturity and short-term investments classified as available for sale is, based upon the judgment of management, unlikely to be recovered, the Company writes down the investment by the amount representing the credit related portion of the decline in value, thereby establishing a new cost basis. The amount of the write-down is recognized in earnings as an OTTI loss. The new cost basis is not changed for subsequent recoveries in fair value. To the extent the Company determines that the amortized cost of the Company's fixed maturity and short-term investments classified as available for sale is likely to be recovered and the decline in value is related to non-credit factors (such as interest rates, market conditions, etc.) and not due to credit related factors, that remaining non-credit portion of the unrealized loss is recorded as a part of accumulated other comprehensive loss in the shareholders' equity section of the Company's Consolidated Balance Sheets. For equity securities classified as available for sale, the Company considers its ability and intent to hold the equity security in an unrealized loss position for a reasonable period of time to allow for a full recovery. When the Company determines that the decline in value of an equity security is other-than-temporary, the Company reduces the cost of the equity security to its fair value and recognizes the loss in the Consolidated Statements of Income and Comprehensive Income. The new cost basis is not changed for subsequent recoveries in fair value. Other investments within the Company's investment portfolio are comprised of hedge funds, private investment funds and other investment funds that generally invest in senior secured bank debt, high yield credit securities, distressed debt, macro strategies, multi-strategy, equity long/short strategies, distressed real estate, and energy sector private equity ("alternative funds"). Other investments are accounted for using the equity method of accounting whereby the initial investment is recorded at cost. The carrying values of these investments are increased or decreased to reflect the Company's share of income or loss, which is included in net investment income, and are decreased for dividends. Due to the timing of the delivery of the final valuations reported by the managers of certain of our alternative funds, our investments in those funds are estimated based on the most recently available information including period end valuation statements, period end estimates, or, in some cases, prior month or quarter valuation statements. 2. Significant accounting policies, cont'd. (e) Cash equivalents and short-term investments Cash equivalents include highly liquid short-term deposits and securities with maturities of ninety days or less at the time of purchase. Cash equivalents are valued at amortized cost, which approximates fair value due to the short-term, liquid nature of these securities. Deposits and securities with maturities greater than ninety days and less than one year are classified as short-term investments. (f) Intangible assets Identifiable intangible assets are amortized in accordance with their useful lives. Goodwill and intangible assets with indefinite useful lives are not amortized but are tested for impairment annually at the beginning of the fourth quarter, or more often if impairment indicators arise. In making an assessment of the value of its goodwill and intangible assets, the Company uses both market based and non-market based valuations. Assumptions underlying these valuations include forecasts of discounted future cash flows and future profits and comparable transactions observed in the market, in addition to an analysis of the Company’s stock price relative to both its book value and its net income. (g) Offering and registration costs Offering and registration costs incurred in connection with equity offerings, including investment banking fees and legal fees, are deducted from the proceeds of the offerings. (h) Foreign exchange Assets and liabilities of foreign operations whose functional currency is not the United States dollar are translated at exchange rates in effect at the balance sheet date. Revenues and expenses of such foreign operations are translated at weighted average exchange rates during the year. The effect of the translation adjustments for foreign operations is included in accumulated other comprehensive loss, net of applicable deferred income taxes. Other monetary assets and liabilities denominated in foreign currencies are revalued at the exchange rates in effect at the balance sheet date with the resulting net foreign exchange gains and losses included in earnings. Revenues and expenses denominated in foreign currencies are translated at the prevailing exchange rate on the transaction date. (i) Derivatives Current accounting guidance requires the recognition of all derivative financial instruments including embedded derivative instruments, as either assets or liabilities in the Consolidated Balance Sheets at fair value. The Company may use various derivative instruments such as foreign exchange forward, future and option contracts; industry loss warranty swaps; interest rate futures, swaps, swaptions, and options; credit default swaps; LIBOR swaps; commodity futures and options; weather swaps and options; loss development covers; and to-be-announced mortgage-backed securities. These derivative instruments are used to manage exposure to interest rate and currency risk, to enhance the efficiency of the Company's investment portfolio, to economically hedge certain risks, and as part of its weather risk management business. Except for a cash flow hedge entered into in 2004 as disclosed in Note 9, Derivatives, these derivative instruments do not qualify, and are not designated, as hedges. Derivatives are recorded at fair value with changes in fair value and any gains or losses are recognized in net realized and unrealized (losses) gains, net foreign exchange (gains) losses, or other underwriting loss in the Consolidated Statements of Income and Comprehensive Income. Where the Company has entered into master netting agreements with counterparties, or the Company has the legal and contractual right to offset positions, the derivative positions may be netted by the counterparty. 2. Significant accounting policies, cont'd. (j) Income taxes The Company accounts for income taxes for its subsidiaries operating in taxable jurisdictions. Deferred income taxes reflect the net tax effect of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. A valuation allowance is provided when it is more likely than not that some portion of the deferred tax assets will not be realized. The accounting guidance allows for the recognition of tax benefits of uncertain tax positions only where the position is more likely than not to be sustained assuming examination by tax authorities. A liability is established for any tax benefit claimed in a tax return in excess of this threshold. Income tax related interest and penalties are included as income tax expense. (k) Stock compensation and other stock plans The Company has a share-based employee and non-employee director equity incentive plan ("2007 Equity Incentive Plan") and other share plans, which are described more fully in Note 16, Stock-based employee compensation and other stock plans. The fair value of the compensation cost incurred under these plans is measured at the grant date and is expensed over the period for which the employee is required to provide services in exchange for the award. Forfeiture benefits are estimated at the time of grant and incorporated in the determination of share-based compensation costs. Awards under the 2007 Equity Incentive Plan generally vest over four years for employees and one year for non-employee directors. (l) Earnings per share The two-class method utilized by the Company is an earnings allocation formula that determines earnings per share for the holders of Endurance Holdings' ordinary shares (also referred to as "common shares") and participating common shares, which includes unvested restricted shares and restricted share units that receive cash dividends, according to dividends declared (or accumulated) and participation rights in undistributed earnings. Net income available to common and participating common shareholders is reduced by the amount of dividends declared in the current period and by the contractual amount of dividends that must be paid for the current period related to the Company's common and participating common shares. Any remaining undistributed earnings are allocated to the common and participating common shareholders to the extent that each security may share in earnings as if all of the earnings for the period had been distributed. In periods of loss, no losses are allocated to participating common shareholders. Instead, all such losses are allocated solely to the common shareholders. Basic earnings per common share are calculated by dividing net income available to common shareholders by the weighted average number of common shares outstanding. The weighted average number of common shares excludes any dilutive effect of outstanding options and convertible securities such as unvested restricted shares and restricted share units. Diluted earnings per common share are based on the weighted average number of common shares and assumes the exercise of all dilutive stock options and the vesting or conversion of all convertible securities such as unvested restricted shares using the two-class method described above. (m) Use of estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported and disclosed amounts 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. Actual results could differ from those estimates. 2. Significant accounting policies, cont'd. (n) Variable interest entity Entities that do not have sufficient equity at risk to allow the entity to finance its activities without additional financial support or in which the equity investors, as a group, do not have the characteristic of a controlling financial interest are referred to as variable interest entities ("VIE"). A VIE is consolidated by the variable interest holder that is determined to have the controlling financial interest (primary beneficiary) as a result of having both the power to direct the activities of a VIE that most significantly impact the VIE's economic performance and the obligation to absorb losses or right to receive benefits from the VIE that could potentially be significant to the VIE. The Company determines whether it is the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the VIE's capital structure, contractual terms, nature of the VIE's operations and purpose and the Company's relative exposure to the related risks of the VIE on the date it becomes initially involved in the VIE. The Company reassesses its VIE determination with respect to an entity on an ongoing basis. See also Note 4, Investments. (o) Non-controlling interests The Company accounts for non-controlling interests in the shareholders' equity section of the Company's Consolidated Balance Sheets in accordance with current accounting guidance regarding consolidation. Net income attributable to non-controlling interest is presented separately in the Company's Consolidated Statements of Income and Comprehensive Income. (p) Reclassifications Certain comparative information has been reclassified to conform to current year presentation. (q) Recent accounting pronouncements In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2014-09, "Revenue from Contracts with Customers" ("ASU 2014-09"). ASU 2014-09 provides comprehensive guidance on the recognition of revenue from customers arising from the transfer of goods and services. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for these goods or services. ASU 2014-09 also provides guidance on accounting for certain contract costs and will also require new disclosures. ASU 2014-09 was to be effective for public business entities in annual and interim periods beginning after December 15, 2016, however, in July 2015, the FASB decided to defer by one year the effective dates of ASU 2014-09, and as a result, ASU 2014-09 will be effective for public business entities in annual and interim period beginning after December 15, 2017. Early adoption is permitted. Based on initial review, the Company has determined that this standard specifically excludes revenue from the following sources: insurance contracts, Topic 944, Financial Services-Insurance and investment income; Topic 320, Investments-Debt and Equity Securities; Topic 323, Investments-Equity Methods and Joint Ventures; Topic 325, Investment-Others; and Topic 815, Derivatives and Hedging. As substantially all of the Company's revenues are subject to the topics above that are excluded from the standard, the Company has determined that this standard will not have a material impact on the Company's Consolidated Financial Statements. In February 2015, the FASB issued ASU 2015-02, "Amendments to the Consolidation Analysis" ("ASU 2015-02"). Under ASU 2015-02, all legal entities are required to evaluate whether they should consolidate certain legal entities. ASU 2015-02 set forth amendments: (1) modifying the evaluation of whether limited partnerships and similar legal entities are VIEs or voting interest entities; (2) eliminating the presumption that a general partner should consolidate a limited partnership; (3) affecting the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships; and (4) providing a scope exception from consolidation guidance for certain reporting entities. ASU 2015-02 was effective for public business entities for annual and interim periods beginning after December 15, 2015. Early adoption was permitted. ASU 2015-02 may be applied retrospectively or by using a modified retrospective approach by recording a cumulative-effect adjustment to equity as of the beginning of the year of adoption. The Company adopted this standard on January 1, 2016 and it did not have a material impact on the Company's Consolidated Financial Statements. 2. Significant accounting policies, cont'd. (q) Recent accounting pronouncements, cont'd. In May 2015, the FASB issued ASU 2015-09, "Disclosures about Short-Duration Contracts" ("ASU 2015-09"). The objective of ASU 2015-09 is to make targeted improvements to disclosure requirements for insurance companies that issue short-duration contracts. The guidance requires additional disclosures of claims development tables, frequency of reported claims, and history of claims duration. This information is required to be disaggregated so that useful information is not obscured by either the inclusion of a large amount of insignificant detail, or the aggregation of items that have significantly different characteristics. ASU 2015-09 was effective for public business entities in annual periods beginning after December 15, 2015, and interim periods within annual periods beginning after December 15, 2016. Early adoption was permitted. ASU 2015-09 should be applied retrospectively. The Company adopted this standard in the fourth quarter of 2016 and has included the appropriate annual disclosures within Note 6, Reserve for losses and loss expenses. The adoption of this standard did not have a material impact on the Company's Consolidated Financial Statements. In January 2016, the FASB issued ASU No. 2016-01, "Recognition and Measurement of Financial Assets and Financial Liabilities" ("ASU 2016-01"). ASU 2016-01 requires equity investments (except those accounted for under the equity method of accounting or those that result in the consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income, simplifies the impairment assessment of equity investments without readily determinable values by requiring a qualitative assessment to identify impairment, eliminates the requirement to disclose the methods and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost, requires the use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes, requires separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the organization has elected to measure the liabilities in accordance with the fair value option, requires the separate presentation of financial assets and financial liabilities by measurement category and for form of years, beginning after December 15, 2015. Early adoption was permitted. The Company adopted ASU 2015-02 effective January 1, 2016 and it did not have material impact on the Company's consolidated statements of operations and financial position.

Acquisition of Montpelier

Acquisition of Montpelier	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Business Combination Disclosure [Text Block]	3. Acquisition of Montpelier On March 31, 2015, the Company announced the signing of a definitive agreement and plan of merger (the "Merger Agreement") with Montpelier and Millhill Holdings Ltd., a direct, wholly-owned subsidiary of the Company ("Merger Sub"), under which Endurance Holdings, through Merger Sub, acquired all of the outstanding common shares of Montpelier. The acquisition of Montpelier was completed on July 31, 2015 (the "Closing Date"). Prior to the closing of the acquisition, Montpelier was a publicly traded company listed on the New York Stock Exchange and headquartered in Bermuda. As of the close of trading on July 31, 2015, the common shares of Montpelier ceased trading. The aggregate consideration for the transaction consisted of the issuance of 20.7 million of the Company’s ordinary shares valued at $1.4 billion and $451.1 million of cash. The cash consideration was funded through a pre-closing dividend from Montpelier of $9.89 per common share, or $451.1 million (the "Special Dividend"). In connection with the acquisition of Montpelier, the Company incurred transaction and integration related expenses of $76.6 million in the year ended December 31, 2015 , which included $19.5 million related to transaction costs, including due diligence, legal, accounting and investment banking fees and expenses, $4.4 million of costs related to the integration of Montpelier and the Company, and $52.7 million of compensation-related costs associated with terminating employees of Montpelier. These expenses have all been reported as a component of corporate expenses. 3. Acquisition of Montpelier, cont'd. Purchase price The Company's total purchase price for Montpelier at July 31, 2015 was calculated as follows: Consideration paid by Endurance Holdings Number of Montpelier common shares outstanding immediately prior to the closing of the acquisition 43,827,753 Exchange ratio 0.472 Total Company ordinary shares 20,686,699 Company ordinary share closing price on July 31, 2015 $ 69.49 Total value of Company ordinary shares $ 1,437,519 Fair value of restricted share units attributable to service period prior to Closing Date (1) $ 33,327 Total consideration $ 1,470,846 Special Dividend paid by Montpelier Number of Montpelier common shares and restricted share units eligible for special dividend 45,611,810 Special dividend paid per Montpelier common share and restricted share unit $ 9.89 Total special dividend consideration paid to Montpelier common shareholders and Montpelier equity award holders $ 451,101 Total consideration received by Montpelier common shareholders and Montpelier equity award holders $ 1,921,947 Less: Special Dividend paid by Montpelier (451,101 ) Net purchase price $ 1,470,846 (1) Outstanding Montpelier restricted share units were assumed by the Company and adjusted as of the Closing Date to represent the right to receive 0.472 Company ordinary shares for each outstanding Montpelier restricted share unit rounded down to the next whole number of Company ordinary shares. The fair value of the Montpelier restricted share units was determined based on the closing price of the Company's ordinary shares on the Closing Date. The resulting fair value of the restricted share units was apportioned as purchase consideration based on service provided to Montpelier as of the Closing Date with the remaining fair value of these restricted share units to be recognized prospectively over the restricted share units' remaining vesting period. Fair value of net assets acquired and liabilities assumed The purchase price was allocated to the acquired assets and liabilities of Montpelier based on estimated fair values on July 31, 2015, the Closing Date, as detailed below. The Company recognized goodwill of $87.6 million primarily attributable to Montpelier's assembled workforce and synergies expected to result upon integration of Montpelier into the Company's operations. The Company estimates that none of the goodwill that was recorded will be deductible for income tax purposes. The allocation of the purchase price was based on information that was available to management at the time the 2015 consolidated financial statements were prepared. The allocation was subject to change as additional information became available within the measurement period, which cannot exceed 12 months from the acquisition date. The fair value recorded for these items may be subject to adjustments, which may impact the individual amounts recorded for assets acquired and liabilities assumed, as well as the residual goodwill. 3. Acquisition of Montpelier, cont'd. The Company identified finite lived intangible assets of $293.2 million , which will be amortized over a weighted average period of 8 years, identifiable indefinite lived intangible assets of $57.6 million , and certain other adjustments to the fair values of the assets acquired, liabilities assumed and shareholders' equity of Montpelier at July 31, 2015 as summarized in the table below: Montpelier shareholders' equity attributable to controlling interest prior to Special Dividend $ 1,560,255 Cash and cash equivalents (Special Dividend on Montpelier common shares and Montpelier equity awards) (451,101 ) Adjusted shareholders' equity of Montpelier as of July 31, 2015 1,109,154 Adjustments for fair value, by applicable balance sheet caption: Assets: Fixed maturity investments, trading at fair value (11,100 ) Deferred acquisition costs (91,713 ) Reinsurance recoverable on unpaid losses (675 ) Other assets (12,459 ) Liabilities: Reserve for losses and loss expenses 10,822 Debt 21,123 Deferred tax liability (18,346 ) Equity: Non-controlling interest 25,615 Total adjustments for fair value by applicable balance sheet caption (76,733 ) Adjustments for fair value of the identifiable intangible assets: Identifiable indefinite lived intangible assets (insurance licenses, Lloyd's syndicate capacity and asset management agreements) 57,600 Identifiable finite lived intangible assets (non-contractual relationships, Lloyd's syndicate distribution channel, renewal rights, value of business acquired ("VOBA"), trade names, non-compete agreements and asset management agreements) 293,200 Total adjustments for fair value by applicable balance sheet caption and identifiable intangible assets 274,067 Estimated fair value of net assets acquired and identifiable intangible assets 1,383,221 Total consideration paid by Endurance Holdings 1,470,846 Estimated total consideration over the fair value of net assets acquired assigned to goodwill $ 87,625 An explanation of the significant fair value adjustments is as follows: • Fixed maturity investments, trading at fair value - To reflect certain investments at fair value; • Deferred acquisition costs - To eliminate Montpelier's deferred acquisition costs; • Other assets - To eliminate deferred debt issuance costs related to Montpelier's existing senior notes and to write off Montpelier's fixed assets and goodwill; • Reserve for losses and loss expenses - To reflect a decrease in net losses and loss expenses due to the addition of a market based risk margin, which represents the cost of capital required by a market participant to assume the net losses and loss expenses of Montpelier, offset by a deduction that represents the discount due to the present value calculation of the unpaid losses and loss expenses based on the expected payout of the net unpaid losses and loss expenses; • Debt - To reflect Montpelier's existing senior notes and trust preferred securities at fair value using indicative market pricing obtained from third-party service providers; • Deferred tax liability - To reflect the deferred tax liability on identifiable intangible assets; • Non-controlling interest - To reflect Montpelier's non-controlling interest at fair value; and 3. Acquisition of Montpelier, cont'd. • Identifiable indefinite lived and finite lived intangible assets - To establish the fair value of identifiable intangible assets related to the acquisition of Montpelier described in detail below. Identifiable intangible assets at July 31, 2015 consisted of the following, and are included in goodwill and other intangible assets on the Company's consolidated balance sheets: Amount Economic Useful Life Key non-contractual relationships $ 71,800 10 Other non-contractual relationships 22,400 3 Trade names 1,800 Various Insurance licenses 1,900 Indefinite Non-compete agreements 5,700 Various Lloyd's syndicate capacity 48,300 Indefinite Lloyd's syndicate distribution channel 18,400 10 Renewal rights 82,100 15 VOBA 88,400 2 Asset management agreements 10,000 Various Identifiable intangible assets at July 31, 2015 $ 350,800 An explanation of the identifiable intangible assets is as follows: • Key non-contractual relationships - these relationships included Montpelier's top brokers and consideration was given to the expectation of the renewal of these relationships and the associated expenses; • Other non-contractual relationships - these relationships consisted of Montpelier's brokers with the exception of those top brokers previously listed above as key non-contractual relationships and consideration was given to the expectation of the renewal of these relationships and the associated expenses; • Trade names - represents the value of the Montpelier and Blue Capital brands acquired; • Insurance licenses - the value of insurance licenses acquired providing the ability to write reinsurance in 15 states of the U.S.; • Non-compete agreements - represent non-compete agreements with key employees of Montpelier; • Lloyd's syndicate capacity - the value of Lloyd's syndicate capacity, which represents Montpelier's authorized premium income limit to write insurance business in the Lloyd's marketplace; • Lloyd's syndicate distribution channel - the value of sales of insurance policies that result directly from relationships between Lloyd's and the brokers in the Lloyd's marketplace; • Renewal rights - the value of policy renewal rights taking into consideration written premium on assumed retention ratios and the insurance cash flows and the associated equity cash flows from these renewal policies over the expected life of the renewals; • VOBA - the expected future losses and expenses associated with the policies that were in-force as of the Closing Date of the transaction were estimated and compared to the future premium remaining expected to be earned. The difference between the risk-adjusted future loss and expenses, discounted to present value and the unearned premium reserve, was estimated to be the VOBA; and • Asset management contracts - represents the value of the Blue Capital asset management contracts acquired. 3. Acquisition of Montpelier, cont'd. Financial results The following table summarizes the results of Montpelier since July 31, 2015 that have been included in the Company's Consolidated Statement of Income and Comprehensive Income for the year ended December 31, 2015 : For the period from July 31, 2015 to December 31, 2015 Total revenues $ 225,899 Net income attributable to the Company's common shareholders (1) 54,768 (1) Includes $52.7 million of compensation-related costs associated with terminating employees of Montpelier. Supplemental pro forma information The following table presents unaudited pro forma consolidated financial information for the years ended December 31, 2015 and 2014 and assumes the acquisition of Montpelier occurred on January 1, 2014. The unaudited pro forma consolidated financial information is provided for informational purposes only and is not necessarily, and should not be assumed to be, an indication of the results that would have been achieved had the transaction been completed as of January 1, 2014 or that may be achieved in the future. The unaudited pro forma consolidated financial information does not give consideration to the impact of possible revenue enhancements, expense efficiencies, synergies or asset dispositions that may result from the acquisition of Montpelier. In addition, unaudited pro forma consolidated financial information does not include the effects of costs associated with any restructuring or integration activities resulting from the acquisition of Montpelier, as they are nonrecurring. Year Ended December 31, 2015 2014 Total revenues $ 2,452,410 $ 2,668,604 Net income available to Endurance Holdings' common shareholders 443,817 388,371 Among other adjustments, and in addition to the fair value adjustments and recognition of goodwill and identifiable intangible assets noted above, other material nonrecurring pro forma adjustments directly attributable to the acquisition of Montpelier principally included certain adjustments to recognize transaction related costs, align accounting policies, amortize fair value adjustments, amortize identifiable indefinite lived intangible assets and recognize related tax impacts.

Investments

Investments	12 Months Ended
	Dec. 31, 2016
Investments [Abstract]
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]	4. Investments Composition of Net Investment Income and of Invested Assets The components of net investment income for the years ended December 31, 2016 , 2015 and 2014 are as follows: 2016 2015 2014 Fixed income investments $ 165,210 $ 132,786 $ 118,084 Equity securities 12,639 8,209 5,689 Other investments 12,442 (13,553 ) 19,609 Cash and cash equivalents 2,824 2,870 2,445 $ 193,115 $ 130,312 $ 145,827 Investment expenses (16,525 ) (16,486 ) (14,284 ) Net investment income $ 176,590 $ 113,826 $ 131,543 4. Investments, cont'd. Contractual maturities of the Company's fixed maturity and short-term investments are shown below as of December 31, 2016 and 2015 . Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. December 31, 2016 December 31, 2015 Amortized Cost Fair Value Amortized Cost Fair Value Due within one year $ 617,655 $ 617,462 $ 622,070 $ 622,248 Due after one year through five years 2,170,111 2,187,173 2,005,456 1,995,502 Due after five years through ten years 887,775 896,388 683,147 676,932 Due after ten years 55,400 58,449 33,168 34,651 Residential mortgage-backed securities 1,448,917 1,461,286 1,301,083 1,311,373 Commercial mortgage-backed securities 615,730 618,848 817,570 812,886 Collateralized loan and debt obligations 369,126 371,256 419,795 405,128 Asset-backed securities 509,595 510,663 510,540 507,255 Total $ 6,674,309 $ 6,721,525 $ 6,392,829 $ 6,365,975 The following table summarizes the fair value of the fixed maturity investments, short-term investments and equity securities classified as trading at December 31, 2016 and 2015 . December 31, 2016 December 31, 2015 Fixed maturity investments U.S. government and agencies securities $ 551,055 $ 319,674 U.S. state and municipal securities 6,006 5,559 Foreign government securities 110,088 49,861 Government guaranteed corporate securities 2,959 38,201 Corporate securities 1,051,200 532,192 Residential mortgage-backed securities 483,444 258,574 Commercial mortgage-backed securities 164,237 127,124 Collateralized loan and debt obligations 98,924 103,219 Asset-backed securities 272,142 152,756 Total fixed maturity investments 2,740,055 1,587,160 Short-term investments 330,199 394,111 Total fixed income investments $ 3,070,254 $ 1,981,271 Equity securities Equity investments $ 16,056 $ 14,676 Preferred equity investments — 553 Total equity securities $ 16,056 $ 15,229 4. Investments, cont'd. In addition to the Company's fixed maturity, short-term and equity investments, the Company invests in alternative funds. The Company's alternative funds are recorded on the Company's balance sheet as "other investments". At December 31, 2016 and 2015 , the Company had invested, net of capital returned, a total of $470.3 million and $737.1 million , respectively, in other investments. At December 31, 2016 and 2015 , the carrying value of other investments was $588.3 million and $872.6 million , respectively. The following table summarizes the composition and redemption restrictions of other investments as of December 31, 2016 and 2015 : December 31, 2016 Market Value Unfunded Commitments Ineligible for Redemption in 2017 Alternative funds Hedge funds $ 482,865 $ — $ 85,963 Private investment funds 76,451 92,214 76,451 Other investment funds 28,992 — 27,518 Total alternative funds 588,308 92,214 189,932 Total other investments $ 588,308 $ 92,214 $ 189,932 December 31, 2015 Market Value Unfunded Commitments Ineligible for Redemption in 2016 Alternative funds Hedge funds $ 704,966 $ — $ 57,876 Private investment funds 80,690 102,070 80,690 Other investment funds 23,465 — 24,958 Total alternative funds 809,121 102,070 163,524 Specialty funds High yield loan funds 63,496 — — Total specialty funds 63,496 — — Total other investments $ 872,617 $ 102,070 $ 163,524 Hedge funds – The redemption frequency of the hedge funds range from monthly to biennially with notice periods from 30 to 90 days. Over one year, it is estimated that the Company can liquidate approximately 82.2% of the hedge fund portfolio, with the remainder over the following two years. Private investment funds – The Company generally has no right to redeem its interest in any private investment funds in advance of dissolution of the applicable partnership. Instead, the nature of these investments is that distributions are received by the Company in connection with the distribution of income or the liquidation of the underlying assets of the applicable limited partnership. It is estimated that the majority of the underlying assets of the limited partnerships would liquidate over 5 to 10 years from inception of the limited partnership. A secondary market, with unpredictable liquidity, exists for limited partner interests in private investment funds. Other investment funds – Other investment funds includes funds on deposit with Lloyd's, which are restricted, and the Company's investment in BCGR, which represents the net carrying value of the Company's investment in BCGR that has not been deployed into the BCGR cell. High yield loan funds – There are generally no restrictions on the Company's right to redeem its interest in high yield loan funds with the exception of certain redemption frequency and notice requirements. The redemption frequency of these funds ranges from monthly to quarterly with notice periods from 30 to 90 days. The Company had no investments in high yield loan funds as of December 31, 2016. 4. Investments, cont'd. Net Realized and Unrealized (Losses) Gains Realized and unrealized gains and losses are recognized in earnings using the first in, first out method. The analysis of gross realized gains and losses, net unrealized gains and losses on trading securities, intangible asset impairment loss, and the change in the fair value of investment-related derivative financial instruments for the years ended December 31, 2016 , 2015 and 2014 are as follows: 2016 2015 2014 Gross realized gains on investment sales $ 39,033 $ 65,881 $ 35,921 Gross realized losses on investment sales (61,752 ) (28,636 ) (16,515 ) Net unrealized gains (losses) on trading securities 12,480 (24,257 ) — Intangible asset impairment loss (1) — — (5,450 ) Change in fair value of derivative financial instruments (2) (2,180 ) (328 ) 327 Net realized and unrealized (losses) gains $ (12,419 ) $ 12,660 $ 14,283 (1) For additional information on the Company's intangible assets, see Note 11, Goodwill and intangible assets. (2) For additional information on the Company's derivative financial instruments, see Note 9, Derivatives. Unrealized Gains and Losses The Company classifies some of its investments in fixed maturity investments, short-term investments and equities as available for sale. The amortized cost, fair value and related gross unrealized gains and losses on the Company's securities classified as available for sale at December 31, 2016 and 2015 are as follows: December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturity investments U.S. government and agencies securities $ 449,638 $ 3,981 $ (2,792 ) $ 450,827 U.S. state and municipal securities 11,560 945 (154 ) 12,351 Foreign government securities 68,539 2,236 (1,944 ) 68,831 Government guaranteed corporate securities 912 46 — 958 Corporate securities 1,078,756 26,481 (8,744 ) 1,096,493 Residential mortgage-backed securities 968,273 21,032 (11,463 ) 977,842 Commercial mortgage-backed securities 452,011 8,790 (6,190 ) 454,611 Collateralized loan and debt obligations 271,361 1,644 (673 ) 272,332 Asset-backed securities 237,177 2,242 (898 ) 238,521 Total fixed maturity investments $ 3,538,227 $ 67,397 $ (32,858 ) $ 3,572,766 Short-term investments 78,506 1 (2 ) 78,505 Total fixed income investments $ 3,616,733 $ 67,398 $ (32,860 ) $ 3,651,271 Equity securities Equity investments $ 461,509 $ 27,948 $ (4,545 ) $ 484,912 Preferred equity investments 175 — (2 ) 173 Total equity securities $ 461,684 $ 27,948 $ (4,547 ) $ 485,085 4. Investments, cont'd. December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturity investments U.S. government and agencies securities $ 499,386 $ 2,561 $ (3,153 ) $ 498,794 U.S. state and municipal securities 16,908 120 (181 ) 16,847 Foreign government securities 110,893 803 (581 ) 111,115 Government guaranteed corporate securities 19,248 311 (7 ) 19,552 Corporate securities 1,323,276 5,698 (11,232 ) 1,317,742 Residential mortgage-backed securities 1,041,540 16,400 (5,141 ) 1,052,799 Commercial mortgage-backed securities 689,078 4,737 (8,053 ) 685,762 Collateralized loan and debt obligations 304,915 796 (3,802 ) 301,909 Asset-backed securities 356,753 585 (2,839 ) 354,499 Total fixed maturity investments $ 4,361,997 $ 32,011 $ (34,989 ) $ 4,359,019 Short-term investments 25,657 28 — 25,685 Total fixed income investments $ 4,387,654 $ 32,039 $ (34,989 ) $ 4,384,704 Equity securities Equity investments $ 527,154 $ 6,835 $ (37,474 ) $ 496,515 Preferred equity investments 15,275 1,946 (151 ) 17,070 Total equity securities $ 542,429 $ 8,781 $ (37,625 ) $ 513,585 4. Investments, cont'd. The following tables summarize, for all available for sale securities in an unrealized loss position at December 31, 2016 and 2015 , the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position. Less than 12 months 12 months or greater Total December 31, 2016 Unrealized Losses (1) Fair Value Unrealized Losses (1) Fair Value Unrealized Losses (1) Fair Value Fixed maturity investments U.S. government and agencies securities $ (2,791 ) $ 289,012 $ (1 ) $ 248 $ (2,792 ) $ 289,260 U.S. state and municipal securities (152 ) 5,288 (2 ) 2,143 (154 ) 7,431 Foreign government securities (446 ) 15,717 (1,498 ) 5,973 (1,944 ) 21,690 Corporate securities (7,512 ) 448,643 (1,232 ) 11,897 (8,744 ) 460,540 Residential mortgage-backed securities (10,082 ) 521,167 (1,381 ) 31,835 (11,463 ) 553,002 Commercial mortgage-backed securities (3,453 ) 174,144 (2,737 ) 76,694 (6,190 ) 250,838 Collateralized loan and debt obligations (223 ) 50,194 (450 ) 81,043 (673 ) 131,237 Asset-backed securities (539 ) 64,109 (359 ) 39,770 (898 ) 103,879 Total fixed maturity investments $ (25,198 ) $ 1,568,274 $ (7,660 ) $ 249,603 $ (32,858 ) $ 1,817,877 Short-term investments (2 ) 4,691 — — (2 ) 4,691 Total fixed income investments $ (25,200 ) $ 1,572,965 $ (7,660 ) $ 249,603 $ (32,860 ) $ 1,822,568 Equity securities Equity investments $ (2,855 ) $ 71,509 $ (1,690 ) $ 17,408 $ (4,545 ) $ 88,917 Preferred equity investments (2 ) 123 — — (2 ) 123 Total equity securities $ (2,857 ) $ 71,632 $ (1,690 ) $ 17,408 $ (4,547 ) $ 89,040 (1) Gross unrealized losses include unrealized losses on non-OTTI and non-credit OTTI securities recognized in accumulated other comprehensive loss at December 31, 2016 . As of December 31, 2016 , 1,090 available for sale securities were in an unrealized loss position aggregating $37.4 million . Of those, 218 securities with aggregated unrealized losses of $9.4 million at December 31, 2016 had been in a continuous unrealized loss position for twelve months or greater. 4. Investments, cont'd. Less than 12 months 12 months or greater Total December 31, 2015 Unrealized Losses (1) Fair Value Unrealized Losses (1) Fair Value Unrealized Losses (1) Fair Value Fixed maturity investments U.S. government and agencies securities $ (2,175 ) $ 347,024 $ (978 ) $ 16,669 $ (3,153 ) $ 363,693 U.S. state and municipal securities (96 ) 9,662 (85 ) 695 (181 ) 10,357 Foreign government securities (404 ) 31,881 (177 ) 3,966 (581 ) 35,847 Government guaranteed corporate securities (7 ) 1,692 — — (7 ) 1,692 Corporate securities (9,222 ) 830,349 (2,010 ) 51,024 (11,232 ) 881,373 Residential mortgage-backed securities (3,378 ) 365,082 (1,763 ) 79,355 (5,141 ) 444,437 Commercial mortgage-backed securities (6,708 ) 436,387 (1,345 ) 42,246 (8,053 ) 478,633 Collateralized loan and debt obligations (3,107 ) 224,520 (695 ) 48,167 (3,802 ) 272,687 Asset-backed securities (2,624 ) 311,814 (215 ) 12,880 (2,839 ) 324,694 Total fixed income investments $ (27,721 ) $ 2,558,411 $ (7,268 ) $ 255,002 $ (34,989 ) $ 2,813,413 Equity securities Equity investments $ (32,021 ) $ 329,280 $ (5,453 ) $ 56,421 $ (37,474 ) $ 385,701 Preferred equity investments (151 ) 7,361 — — (151 ) 7,361 Total equity securities $ (32,172 ) $ 336,641 $ (5,453 ) $ 56,421 $ (37,625 ) $ 393,062 (1) Gross unrealized losses include unrealized losses on non-OTTI and non-credit OTTI securities recognized in accumulated other comprehensive loss at December 31, 2015 . As of December 31, 2015 , 1310 available for sale securities were in an unrealized loss position aggregating $72.6 million . Of those, 158 securities with aggregated unrealized losses of $12.7 million at December 31, 2015 had been in a continuous unrealized loss position for twelve months or greater. The decrease in gross unrealized losses on the Company's fixed income investments and equity securities at December 31, 2016 compared to December 31, 2015 was primarily due to tightening of credit spreads and strong equity markets during the year, partially offset by an increase in interest rates, rather than any actual credit losses on these securities. As of December 31, 2016, the Company did not have the intent to sell any of the remaining fixed income investments in an unrealized loss position and determined that it was unlikely that the Company would be required to sell those securities in an unrealized loss position. During the year ended December 31, 2016 , the Company impaired certain equity securities that were in an unrealized loss position for more than twelve consecutive months and therefore recognized in earnings total other-than-temporary impairments of $10.8 million ( 2015 - $3.7 million ; 2014 - $0.6 million ). As of December 31, 2016, the Company did not have the intent to sell any of the the remaining equity securities in an unrealized loss position. Other Investments The Company is involved in the normal course of business with VIEs primarily as a passive investor in residential and commercial mortgage-backed securities and through its interests in various other investments that are structured as limited partnerships considered to be third party VIEs. The Company determines whether it is the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the VIE's capital structure, contractual terms, nature of the VIE's operations and purpose, and the Company's relative exposure to the related risks of the VIE on the date it becomes initially involved in the VIE. The Company determined that it was not the primary beneficiary for any of these investments as of December 31, 2016 and 2015 . The Company believes its exposure to loss with respect to these investments is generally limited to the investment carrying amounts reported in the Company's Consolidated Balance Sheets and any unfunded investment commitments. 4. Investments, cont'd. Collateralized Reinsurance Entities As of December 31, 2016 , Endurance Holdings and Endurance Bermuda together owned 33.3% of BCRH. BCRH is considered a VIE under U.S. GAAP and the Company has determined that it is BCRH's primary beneficiary. As a result, the Company fully consolidates the assets, liabilities and operations of BCRH and its subsidiaries within its Consolidated Financial Statements. The interests in BCRH and its subsidiaries that the Company fully consolidates that are attributable to third-party investors are reported within the Company's Consolidated Financial Statements as non-controlling interests. BCRH's shareholder rights do not include redemption features within the control of the third party shareholders. The Company reassesses its VIE determination with respect to BCRH on an ongoing basis. As of December 31, 2016 , Endurance Bermuda owned 25.2% of BCGR. BCGR is considered a "voting interest entity" under U.S. GAAP and, because the Company owns less than 50% of its outstanding ordinary shares, the Company does not consolidate BCGR's assets, liabilities or operations within its Consolidated Financial Statements. However, the BCGR Cell and Blue Water Re, the Company's wholly-owned Bermuda-based special purpose insurance vehicle, are considered VIEs under U.S. GAAP and the Company has determined that it is the primary beneficiary of these entities. Therefore, as funds held in BCGR are deployed into the BCGR Cell, and ultimately into Blue Water Re, they are included in the Company's consolidated financial statements. Conversely, as funds previously deployed by BCGR and the BCGR Cell into Blue Water Re are returned to BCGR, they are no longer included in the Company's consolidated financial statements. The interests in the BCGR Cell and Blue Water Re that the Company fully consolidate that are attributable to third-party investors are reported within the Company's consolidated financial statements as non-controlling interests. BCGR's shareholder rights do not include redemption features within the control of the third party shareholders. The Company reassesses its VIE determinations with respect to the BCGR Cell and Blue Water Re on an ongoing basis. The following table summarizes the movements in the non-redeemable non-controlling interests balance for the year ended December 31, 2016 and from the acquisition date, July 31, 2015 to December 31, 2015 : Year Ended December 31, 2016 Five Months Ended December 31, 2015 Non-controlling interests, beginning balance $ 267,810 $ 258,529 Income attributable to third-party investments in the BCGR Cell 14,577 5,526 Income attributable to third-party investments in BCRH 9,553 5,490 Net income attributable to non-controlling interests 24,130 11,016 Net preferred share redemption attributable to third-party investments in the BCGR Cell (1) (19,799 ) — Net investments attributable to third-parties in BCRH 72 20 Net change in third-party investments in non-controlling interests (19,727 ) 20 Dividends declared by BCRH attributable to non-controlling interests (12,519 ) (1,755 ) Non-controlling interests - ending balance $ 259,694 $ 267,810 (1) The redemption from the BCGR Cell was required to fund expenses, repay debt and fund dividends by BCGR.

Fair Value Measurement

Fair Value Measurement	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurement	5. Fair value measurement The Company determines the fair value of its fixed maturity investments, short-term investments, equity securities, debt, and other assets and liabilities in accordance with current accounting guidance, which defines fair value and establishes a fair value hierarchy based on inputs to the various valuation techniques used for each fair value measurement. The Company determines the estimated fair value of each individual security utilizing the highest level inputs available. Valuation inputs by security type may include the following: • Government and agencies fixed maturity securities – These securities are generally priced by pricing services or index providers. The pricing services or index providers may use current market trades for securities with similar quality, maturity and coupon. If no such trades are available, the pricing service typically uses analytical models which may incorporate option adjusted spreads, daily interest rate data and market/sector news. The Company generally classifies the fair values of government and agencies securities in Level 2. Current issue U.S. government securities are generally valued based on Level 1 inputs, which use the market approach valuation technique. • Government guaranteed corporate fixed maturity securities – These securities are generally priced by pricing services or index providers. The pricing service or index providers may use current market trades for securities with similar quality, maturity and coupon. If no such trades are available, the pricing service typically uses analytical spread models which may incorporate inputs from the U.S. treasury curve or LIBOR. The Company generally classifies the fair values of its government guaranteed corporate securities in Level 2. • Corporate fixed maturity securities – These securities are generally priced by pricing services or index providers. The pricing services or index providers typically use discounted cash flow models that incorporate benchmark curves for treasury, swap and high issuance credits. Credit spreads are developed from current market observations for like or similar securities. The Company generally classifies the fair values of its corporate securities in Level 2. • Equity securities – These securities are generally priced by pricing services or index providers. Depending on the type of underlying equity security or equity fund, the securities are priced by pricing services or index providers based on quoted market prices in active markets or through a discounted cash flow model that incorporates benchmark curves for treasury, swap and credit for like or similar securities. The Company generally classifies the fair values of its equity securities in Level 1 or 2. • Structured securities including agency and non-agency, residential and commercial mortgage, asset-backed securities and collateralized loan and debt obligations – These securities are generally priced by broker/dealers. Broker/dealers may use current market trades for securities with similar qualities. If no such trades are available, inputs such as bid and offer, prepayment speeds, the U.S. treasury curve, swap curve and cash settlement may be used in a discounted cash flow model to determine the fair value of a security. The Company generally classifies the fair values of its structured securities in Level 2. • Other assets and liabilities – A portion of other assets and liabilities are composed of a variety of derivative instruments used to enhance the efficiency of the investment portfolio and economically hedge certain risks. These instruments are generally priced by pricing services, broker/dealers and/or recent trading activity. The market value approach valuation technique is used to estimate the fair value for these derivatives based on significant observable market inputs. Certain derivative instruments are priced by pricing services based on quoted market prices in active markets. These derivative instruments are generally classified in Level 1. Other derivative instruments are priced using industry valuation models and are considered Level 2, as the inputs to the valuation model are based on observable market inputs. Also included in this line item are proprietary, non-exchange traded derivative-based risk management products primarily used to address weather and energy risks. The trading market for these weather derivatives are generally linked to energy and agriculture commodities, weather and other natural phenomena. In instances where market prices are not available, the Company uses industry or internally developed valuation techniques such as spread option, Black Scholes, quanto and simulation modeling to determine fair value and classifies these in Level 3. These models may reference prices for similar instruments. • Debt – Outstanding debt consists of the Company's 7% Senior Notes due July 15, 2034 and 4.7% Senior Notes due October 15, 2022 (the "Senior Notes") and the Trust Preferred Securities. The fair values of these securities were obtained from a third party pricing service and pricing was based on the spread above the risk-free yield curve. These spreads are generally obtained from the new issue market, secondary trading and broker-dealer quotes. As these spreads and the yields for the risk-free yield curve are observable market inputs, the fair values of the Senior Notes and the Trust Preferred Securities are classified in Level 2. 5. Fair value measurement, cont'd. The carrying values of cash and cash equivalents, accrued investment income, other investments, net receivable on sales of investments, net payable on purchases of investments, the amount outstanding under the BCRH Credit Agreement and other financial instruments not described above approximated their fair values at December 31, 2016 and 2015 . The following table sets forth the Company's fixed maturity investments, equity securities, short-term investments, other assets and liabilities and debt categorized by the level within the hierarchy in which the fair value measurements fall at December 31, 2016 : Fair Value Measurements at December 31, 2016 Total at December 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Fixed maturity investments U.S. government and agencies securities $ 1,001,882 $ 51,827 $ 950,055 $ — U.S. state and municipal securities 18,357 — 18,357 — Foreign government securities 178,919 — 178,919 — Government guaranteed corporate securities 3,917 — 3,917 — Corporate securities 2,147,693 — 1,968,056 179,637 Residential mortgage-backed securities 1,461,286 — 1,461,286 — Commercial mortgage-backed securities 618,848 — 618,848 — Collateralized loan and debt obligations 371,256 — 371,256 — Asset-backed securities 510,663 — 510,663 — Total fixed maturity investments 6,312,821 51,827 6,081,357 179,637 Equity securities Equity investments 500,968 184,251 316,717 — Preferred equity investments 173 — 173 — Total equity securities 501,141 184,251 316,890 — Short-term investments 408,704 — 408,654 50 Other assets (see Note 9) 166,716 1,953 123,681 41,082 Total assets $ 7,389,382 $ 238,031 $ 6,930,582 $ 220,769 Liabilities Other liabilities (see Note 9) $ 84,069 $ 2,772 $ 55,051 $ 26,246 Debt 770,704 — 770,704 — Total liabilities $ 854,773 $ 2,772 $ 825,755 $ 26,246 During the year ended December 31, 2016 , $79.3 million of investments, consisting primarily of corporate securities, that were previously held by the Company indirectly in an equity fund as part of the Company's other investments, were transferred into Level 3 as no observable inputs were available, and $7.3 million of primarily collateralized loan and debt obligations, asset-backed and commercial mortgage-backed securities were transferred out of Level 3 to Level 2 during the year as market activity for these securities increased and observable inputs became available. During the year ended December 31, 2016 , $18.4 million of U.S. government and agencies securities were transferred from Level 1 to Level 2 as they no longer qualified as on the run U.S. treasury securities. 5. Fair value measurement, cont'd. The following table sets forth the Company's fixed maturity investments, equity securities, short-term investments, other assets and liabilities and debt categorized by the level within the hierarchy in which the fair value measurements fall at December 31, 2015 : Fair Value Measurements at December 31, 2015 Total at December 31, 2015 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Fixed maturity investments U.S. government and agencies securities $ 818,468 $ 37,741 $ 780,727 $ — U.S. state and municipal securities 22,406 — 22,406 — Foreign government securities 160,976 — 160,976 — Government guaranteed corporate securities 57,753 — 57,753 — Corporate securities 1,849,934 — 1,739,002 110,932 Residential mortgage-backed securities 1,311,373 — 1,311,373 — Commercial mortgage-backed securities 812,886 — 812,174 712 Collateralized loan and debt obligations 405,128 — 404,319 809 Asset-backed securities 507,255 — 507,255 — Total fixed maturity investments $ 5,946,179 $ 37,741 $ 5,795,985 $ 112,453 Equity securities Equity investments 511,191 275,086 236,105 — Preferred equity investments 17,623 — 17,623 — Total equity securities $ 528,814 $ 275,086 $ 253,728 $ — Short-term investments 419,796 — 419,796 — Other assets (see Note 9) 68,892 4 27,385 41,503 Total assets $ 6,963,681 $ 312,831 $ 6,496,894 $ 153,956 Liabilities Other liabilities (see Note 9) $ 46,088 $ — $ 4,059 $ 42,029 Debt 737,974 — 737,974 — Total liabilities $ 784,062 $ — $ 742,033 $ 42,029 During the year ended December 31, 2015 , $131.2 million of investments, consisting primarily of corporate securities acquired from Montpelier, were transferred into Level 3 as no observable inputs were available, and $12.4 million of primarily collateralized loan and debt obligations, asset-backed and commercial mortgage-backed securities were transferred out of Level 3 to Level 2 during the year as market activity for these securities increased and observable inputs became available. During the year ended December 31, 2015 , $11.8 million of U.S. government and agencies securities were transferred from Level 1 to Level 2 as they no longer qualified as on the run U.S. treasury securities. Level 3 assets represented 3.0% and 2.2% of the Company's total available for sale and trading investments and derivative instruments at December 31, 2016 and 2015 , respectively. At December 31, 2016 and 2015, Level 3 securities were primarily comprised of corporate securities and weather derivatives. There were no material changes in the Company's valuation techniques for the year ended December 31, 2016 and 2015. 5. Fair value measurement, cont'd. Other assets and other liabilities measured at fair value included assets of $41.1 million ( 2015 - $41.5 million ) and liabilities of $26.2 million ( 2015 - $42.0 million ) related to proprietary, non-exchange traded derivative-based risk management products used in the Company's weather risk management business, and hedging and trading activities related to these risks. In instances where market prices are not available, the Company may use industry or internally developed valuation techniques such as historical analysis and simulation modeling to determine fair value and are considered Level 3. Observable and unobservable inputs to these valuation techniques vary by contract requirements and commodity type, are validated using market-based or independently sourced parameters where applicable and may typically include the following: • Observable inputs: contract price, notional, option strike, term to expiry, interest rate, contractual limits, temperature, rainfall, windspeed, wave height, snow fall, cyclone category; • Unobservable inputs: correlation, composite weather variable; and • Both observable and unobservable: forward commodity price. The Company's weather curves are determined by taking the average payouts for each transaction within its portfolio utilizing detrended historical weather measurements. The Company's commodity curves are determined using historical market data scaled to currently observed market prices. The range of each unobservable input could vary based on the specific commodity, including, but not limited to natural gas, electricity, crude, liquids, temperature or precipitation. Due to the diversity of the portfolio, the range of unobservable inputs could be wide-spread as reflected in the below table on quantitative information. The unobservable inputs are validated at each reporting period and are only changed when corroborated by evidence such as similar market transactions, third-party pricing services and/or broker or dealer quotations or other empirical market data. Changes in any or all of the unobservable inputs listed above may contribute positively or negatively to the overall portfolio fair value depending upon the underlying position. In general, movements in weather curves are the largest contributing factor that impacts fair value. 5. Fair value measurement, cont'd. Below is a summary of quantitative information regarding the significant observable and unobservable inputs used in determining the fair value of the net weather and energy related derivative assets and liabilities classified in Level 3 that are measured at fair value on a recurring basis at December 31, 2016 and 2015 : December 31, 2016 Fair Value (Level 3) Valuation Techniques Inputs Range Low High (Commodity curve in U.S. dollars in thousands) Net weather and energy related derivative assets $ 14,836 Historical Analysis and Simulation Correlation 0 1 Temperature -15F 115F Composite weather variable -25 deg. 45 deg. Rainfall 0" 2" Windspeed 0.01 m/s 25 m/s Wave height 0 m 25 m Commodity curve $ (1 ) $ 14 December 31, 2015 Fair Value (Level 3) Valuation Techniques Inputs Range Low High (Commodity curve in U.S. dollars in thousands) Net weather and energy related derivative liabilities $ 526 Historical Analysis and Simulation Correlation 0 1 Temperature -15F 115F Composite weather variable -25 deg. 45 deg. Rainfall 0" 2" Windspeed 0.01 m/s 25 m/s Snowfall 0" 18" Cyclone (category) — 5 Commodity curve $ — $ 13 5. Fair value measurement, cont'd. The following tables present a reconciliation of the beginning and ending balances for all assets and liabilities measured at fair value on a recurring basis using Level 3 inputs during the years ended December 31, 2016 and 2015 . December 31, 2016 Fixed maturity investments Other assets Total assets Other liabilities Level 3, beginning of year $ 112,453 $ 41,503 $ 153,956 $ (42,029 ) Total equity income and losses and realized and unrealized gains and losses included in earnings 4,321 — 4,321 — Total income and losses included in other underwriting loss — 5,796 5,796 90 Change in unrealized gains and losses included in other comprehensive (loss) income 263 — 263 — Purchases 48,572 — 48,572 — Issues — 22,571 22,571 (34,219 ) Sales (57,987 ) — (57,987 ) — Settlements — (28,788 ) (28,788 ) 49,912 Transfers into Level 3 79,332 — 79,332 — Transfers out of Level 3 (7,267 ) — (7,267 ) — Level 3, end of year $ 179,687 $ 41,082 $ 220,769 $ (26,246 ) December 31, 2015 Fixed maturity investments Other assets Total assets Other liabilities Level 3, beginning of year $ 12,290 $ 25,615 $ 37,905 $ (35,366 ) Total equity income and losses and realized and unrealized gains and losses included in earnings (2,785 ) — (2,785 ) — Total income and losses included in other underwriting loss — (2,951 ) (2,951 ) 5,062 Change in unrealized gains and losses included in other comprehensive (loss) income (180 ) — (180 ) — Purchases 13 4,750 4,763 (4,231 ) Issues — 21,559 21,559 (34,114 ) Sales (15,695 ) — (15,695 ) — Settlements — (7,470 ) (7,470 ) 26,620 Transfers into Level 3 131,215 — 131,215 — Transfers out of Level 3 (12,405 ) — (12,405 ) — Level 3, end of year $ 112,453 $ 41,503 $ 153,956 $ (42,029 )

Reserve For Losses And Loss Exp

Reserve For Losses And Loss Expenses	12 Months Ended
	Dec. 31, 2016
Insurance Loss Reserves [Abstract]
Reserve For Losses And Loss Expenses	6. Reserve for losses and loss expenses Activity in the reserve for losses and loss expenses for the years ended December 31, 2016 , 2015 and 2014 is summarized as follows: 2016 2015 2014 Gross reserve for losses and loss expenses, January 1 $ 4,510,415 $ 3,846,859 $ 4,002,259 Reinsurance recoverable on unpaid losses 907,944 670,795 593,755 Net reserve for losses and loss expenses, January 1 3,602,471 3,176,064 3,408,504 Incurred related to: Current year 1,542,602 1,160,572 1,203,977 Prior years (221,550 ) (243,464 ) (233,815 ) Total incurred 1,321,052 917,108 970,162 Paid related to: Current year (295,863 ) (265,898 ) (439,169 ) Prior years (890,027 ) (867,739 ) (719,043 ) Total paid (1,185,890 ) (1,133,637 ) (1,158,212 ) Amounts acquired (1) — 675,019 — Foreign currency translation and other (45,624 ) (32,083 ) (44,390 ) Net reserve for losses and loss expenses, December 31 3,692,009 3,602,471 3,176,064 Reinsurance recoverable on unpaid losses 1,213,129 907,944 670,795 Gross reserve for losses and loss expenses, December 31 $ 4,905,138 $ 4,510,415 $ 3,846,859 (1) Represents the fair value of Montpelier's reserve for losses and loss expenses and reinsurance recoverable acquired at July 31, 2015. During 2016 , the Company's estimated ultimate losses for prior accident years were reduced by $221.6 million ( 2015 - $243.5 million ; 2014 - $233.8 million ) due to lower claims emergence than originally estimated by the Company. During 2016 , the Company experienced favorable reserve development of $144.4 million across each line of business in the Reinsurance segment and $77.1 million of favorable development across each line of business in the Insurance segment. During 2015 , the Company experienced favorable development of $161.5 million across each line of business in the Reinsurance segment and $82.0 million of favorable development across each line of business in the Insurance segment. During 2014 , the Company experienced favorable development of $153.2 million across each line of business in the Reinsurance segment and $80.6 million of favorable development across each line of business in the Insurance segment. Reserves for losses and loss expenses are based in part upon the estimation of losses resulting from catastrophic events. Estimation of these losses and loss expenses are based upon the Company's historical claims experience and is inherently difficult because of the Company's short operating history and the possible severity of catastrophe claims. Therefore, the Company uses both proprietary and commercially available models, as well as historical reinsurance industry catastrophe claims experience in addition to its own historical data for purposes of evaluating trends and providing an estimate of ultimate claims costs. A significant portion of the Company's contracts and policies cover excess layers for high severity exposures. Underwriting results and ultimate claims payments for this type of coverage are therefore not typically reported to the Company until later in the contract and policy lives. As a result, the level of losses reported to date is not necessarily indicative of expected future results. 6. Reserve for losses and loss expenses, cont'd. The Company monitors the performance of its underwriting operations through review of discrete information related to its two reportable segments, Insurance and Reinsurance. Within each of these segments, the Company writes a variety of different types of insurance and reinsurance. For reporting purposes, management has combined its many business units, including within the Insurance segment - agriculture, casualty and other specialty, professional lines and property, marine/energy and aviation; and within the Reinsurance segment- catastrophe, property, casualty, professional lines and specialty. Management believes that the businesses combined within these business lines have similarities that make it appropriate to evaluate each as a group. The Company has included reserves acquired as part of its acquisition of Montpelier on a retrospective basis within its existing lines of business. In addition, the Company has restated all periods reflected in the various tables at the foreign exchange rates as of December 31, 2016. The Company incorporates a variety of actuarial methods and judgments in its reserving process. Two key inputs in the various actuarial methods employed by the Company are initial expected loss ratios and expected loss reporting patterns. These key inputs impact the potential variability in the estimate of the reserve for losses and loss expenses and are applicable to each of the Company's business segments. The Company's loss and loss expense reserves consider and reflect, in part, deviations resulting from differences between expected loss and actual loss reporting as well as judgments relating to the weights applied to the reserve levels indicated by the actuarial methods. Expected loss reporting patterns are based upon internal and external historical data and assumptions regarding claims reporting trends over a period of time that extends beyond the Company's own operating history. IBNR Reserves and Claims Frequency The Company establishes loss and loss expense reserves to provide for the estimated costs of paying claims under insurance policies and reinsurance contracts underwritten by the Company. These reserves include estimates for both claims that have been reported and those that have been incurred but not reported and include estimates of all expenses associated with processing and settling these claims. Estimating the ultimate cost of future claims and claim adjustment expenses is based on management judgment and thus, actual losses incurred may vary significantly from management's estimates. For insurance policies, the Company generally receives claims notices that are recorded by the claims staff within our underwriting, financial and claims systems. When we are notified of insured losses or discover potential losses as part of our claims audits, claims personnel record a case reserve as appropriate for the estimated amount of the exposure at that time. Reserves are also established to provide for the estimated expense of settling claims, including legal and other fees and the general expenses of administering the claims adjustment process. The Company counts an insurance claim when either an indemnity or allocated adjustment expense amount has been paid, or at any quarter end, the Company recorded a case reserve. The Company's Reinsurance segment and line of business include contracts written on a proportional or excess of loss basis. For proportional reinsurance business, the Company receives a bordereau indicating the Company's share of losses as well as other financial items. The Company does not have direct access to claims frequency information, and as such, the number of claims represented by the losses reported cannot be determined by the Company. The Company has determined that it is impracticable to provide claims frequency information related to its reinsurance contracts written on a proportional basis. The amount of IBNR related to proportional reinsurance contracts was $700.0 million at December 31, 2016. For Reinsurance contracts written on an excess of loss basis, the Company has developed claims frequency information. The Company determines claims frequency for excess of loss contracts when either a loss has been paid or at any quarter-end, the Company recorded a case reserve. Claims are counted by contract. 6. Reserve for losses and loss expenses, cont'd. The following tables show, by segment by line of business, the incurred losses and loss expenses and cumulative paid losses and loss expenses, net of reinsurance, as of December 31, 2016 . The following also includes the amount of IBNR reserves recorded as well as the cumulative number of reported claims for the Insurance segment lines of business and only excess of loss reinsurance contracts for the Reinsurance segment lines of business. Insurance Segment - Agriculture Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ — $ — $ — $ — $ — $ — $ — $ — $ — $ — $ — — 2008 — 333,380 318,709 313,296 313,800 313,814 313,938 313,834 313,834 313,834 — 30,036 2009 — — 298,914 284,277 280,798 281,667 281,594 281,365 281,365 281,365 — 26,540 2010 — — — 305,131 280,330 280,409 280,166 280,008 280,008 280,008 — 18,331 2011 — — — — 520,388 509,531 508,424 507,930 507,847 507,847 — 37,061 2012 — — — — — 581,455 576,836 573,376 572,995 572,469 — 38,297 2013 — — — — — — 566,483 563,158 562,122 562,826 — 44,138 2014 — — — — — — — 451,710 451,843 449,705 — 53,886 2015 — — — — — — — — 241,501 227,634 — 39,508 2016 — — — — — — — — — 200,353 20,453 29,353 Total $ 3,396,041 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ — $ — $ — $ — $ — $ — $ — $ — $ — $ — 2008 — 239,498 310,235 313,196 313,708 313,722 313,859 313,834 313,834 313,834 2009 — — 178,206 281,996 280,468 280,991 281,058 281,365 281,365 281,365 2010 — — — 144,296 279,397 279,768 279,859 280,008 280,008 280,008 2011 — — — — 461,335 506,905 507,790 507,918 507,847 507,847 2012 — — — — — 478,797 573,781 572,885 572,995 572,469 2013 — — — — — — 438,034 562,046 562,075 561,652 2014 — — — — — — — 352,202 448,046 449,705 2015 — — — — — — — — 122,696 222,212 2016 — — — — — — — — — 75,894 Total $ 3,264,986 Reserve for losses and loss expenses, net of reinsurance $ 131,055 6. Reserve for losses and loss expenses, cont'd. Insurance Segment - Casualty & Other Specialty Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 254,678 $ 251,840 $ 228,021 $ 232,156 $ 232,186 $ 235,482 $ 213,895 $ 197,246 $ 196,072 $ 191,927 $ 20,274 988 2008 — 285,334 296,079 333,844 366,479 363,094 347,477 339,927 328,153 312,759 35,706 1,602 2009 — — 198,689 240,235 237,368 237,101 234,983 230,594 218,900 206,077 24,553 2,509 2010 — — — 150,636 179,854 179,208 175,922 160,450 135,214 122,748 19,995 2,738 2011 — — — — 151,344 169,803 222,470 226,274 201,355 186,588 48,836 4,319 2012 — — — — — 164,568 182,924 187,141 183,644 179,929 73,724 6,268 2013 — — — — — — 153,377 165,853 205,041 230,081 81,540 6,790 2014 — — — — — — — 120,226 132,184 141,970 84,031 7,969 2015 — — — — — — — — 145,828 156,771 77,472 8,717 2016 — — — — — — — — — 165,558 137,608 5,305 Total $ 1,894,408 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 9,090 $ 38,777 $ 66,865 $ 103,283 $ 124,887 $ 139,923 $ 144,982 $ 152,297 $ 159,687 $ 163,236 2008 — 36,479 82,811 129,840 169,331 200,021 239,185 255,585 261,201 266,264 2009 — — 15,098 50,815 83,210 103,922 139,011 150,241 160,903 168,351 2010 — — — 863 4,279 27,379 64,917 83,634 88,737 96,785 2011 — — — — 3,279 14,468 30,074 54,598 91,817 97,285 2012 — — — — — 3,707 16,190 32,686 51,381 75,508 2013 — — — — — — 3,145 15,581 89,771 119,524 2014 — — — — — — — 3,389 18,914 36,446 2015 — — — — — — — — 18,426 49,196 2016 — — — — — — — — — 14,281 Total $ 1,086,876 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 30,599 Adjustment for unallocated claim expenses 43,666 Reserve for losses and loss expenses, net of reinsurance $ 881,797 6. Reserve for losses and loss expenses, cont'd. Insurance Segment - Professional Lines Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 52,739 $ 110,525 $ 150,972 $ 120,358 $ 119,243 $ 117,895 $ 113,520 $ 116,711 $ 125,496 $ 122,969 $ 47 232 2008 — 62,838 62,586 83,358 88,047 96,887 109,471 127,641 138,119 164,412 3,932 379 2009 — — 100,914 118,432 104,421 106,597 109,441 99,973 92,165 93,803 5,728 1,039 2010 — — — 108,369 105,611 101,591 92,931 82,421 74,856 69,387 9,860 1,594 2011 — — — — 102,012 98,353 99,466 79,988 98,989 105,619 15,265 1,232 2012 — — — — — 101,872 103,358 101,426 79,591 69,333 18,080 1,233 2013 — — — — — — 78,988 79,732 70,564 61,499 27,377 1,255 2014 — — — — — — — 64,437 66,524 57,446 29,232 2,599 2015 — — — — — — — — 74,823 72,559 58,966 3,464 2016 — — — — — — — — — 107,761 99,005 3,814 Total $ 924,788 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 83 $ 987 $ 1,744 $ 62,321 $ 90,128 $ 100,560 $ 100,693 $ 110,254 $ 120,328 $ 122,867 2008 — 54 1,898 14,027 15,888 16,613 48,997 72,576 98,770 113,175 2009 — — 1,045 8,755 32,193 38,000 56,126 73,072 77,628 80,201 2010 — — — 1,932 16,014 27,557 36,506 46,982 48,978 51,885 2011 — — — — 2,367 11,766 21,266 33,639 71,782 85,003 2012 — — — — — 2,582 13,185 22,237 29,854 35,678 2013 — — — — — — 2,193 13,807 21,289 26,783 2014 — — — — — — — 1,167 7,081 20,020 2015 — — — — — — — — 1,243 7,130 2016 — — — — — — — — — 2,324 Total $ 545,066 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 61 Adjustment for unallocated claim expenses 26,477 Reserve for losses and loss expenses, net of reinsurance $ 406,260 6. Reserve for losses and loss expenses, cont'd. Insurance Segment - Property, Marine/Energy & Aviation Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 45,128 $ 32,772 $ 25,714 $ 28,766 $ 29,071 $ 28,925 $ 33,206 $ 33,741 $ 34,083 $ 32,680 $ — 201 2008 — 113,427 104,626 84,425 74,111 84,093 80,158 78,176 78,178 77,373 13 459 2009 — — 60,589 48,196 23,651 21,225 19,933 19,423 19,780 19,341 33 568 2010 — — — 93,741 54,986 48,033 42,918 41,703 42,202 43,240 992 1,423 2011 — — — — 163,234 139,932 125,588 124,243 127,840 133,297 256 2,486 2012 — — — — — 172,535 137,329 123,134 121,281 121,873 405 2,704 2013 — — — — — — 115,600 101,878 85,794 80,971 3,933 3,145 2014 — — — — — — — 136,748 114,243 102,002 7,588 4,405 2015 — — — — — — — — 183,192 184,867 18,890 6,281 2016 — — — — — — — — — 234,235 72,271 6,600 Total $ 1,029,879 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 10,626 $ 19,644 $ 21,987 $ 22,614 $ 23,482 $ 23,780 $ 32,561 $ 33,546 $ 34,084 $ 32,671 2008 — 40,140 57,685 62,922 64,434 75,187 75,042 77,234 77,910 77,239 2009 — — 11,014 16,967 18,120 18,657 18,887 19,075 19,407 19,261 2010 — — — 11,680 29,150 33,938 36,306 38,880 40,782 41,802 2011 — — — — 17,871 63,710 82,967 103,301 117,337 123,496 2012 — — — — — 18,709 79,533 87,216 102,447 108,983 2013 — — — — — — 20,929 57,243 66,851 71,423 2014 — — — — — — — 26,491 60,418 79,321 2015 — — — — — — — — 52,121 131,697 2016 — — — — — — — — — 77,448 Total $ 763,341 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 3 Adjustment for unallocated claim expenses 7,855 Reserve for losses and loss expenses, net of reinsurance $ 274,396 6. Reserve for losses and loss expenses, cont'd. Reinsurance Segment - Catastrophe Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 168,640 $ 126,561 $ 104,527 $ 102,855 $ 91,502 $ 88,252 $ 86,273 $ 90,379 $ 97,851 $ 102,929 $ 153 192 2008 — 405,190 378,838 389,111 392,668 384,117 382,382 382,068 384,864 381,551 317 336 2009 — — 102,411 74,817 59,051 55,933 55,229 56,944 58,910 60,788 559 204 2010 — — — 272,094 234,576 226,060 226,208 231,531 237,677 224,323 1,394 265 2011 — — — — 622,350 591,965 589,614 603,680 612,274 624,448 4,640 574 2012 — — — — — 245,011 180,145 163,109 154,240 151,003 3,884 345 2013 — — — — — — 157,097 129,469 127,984 124,311 1,454 315 2014 — — — — — — — 141,173 126,822 126,512 3,156 229 2015 — — — — — — — — 60,465 47,255 4,057 224 2016 — — — — — — — — — 137,357 27,654 216 Total $ 1,980,477 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 31,590 $ 85,271 $ 87,267 $ 91,214 $ 83,511 $ 82,285 $ 80,852 $ 88,684 $ 97,279 $ 102,497 2008 — 154,382 255,721 316,023 353,658 375,455 378,322 380,366 382,431 380,409 2009 — — 26,869 45,763 48,440 49,847 51,013 54,189 57,551 59,865 2010 — — — 58,556 124,322 152,264 173,341 193,340 207,716 208,329 2011 — — — — 230,619 385,304 495,351 561,864 593,831 615,504 2012 — — — — — 56,614 105,745 126,802 134,288 136,862 2013 — — — — — — 34,236 83,259 106,983 116,996 2014 — — — — — — — 49,337 107,546 117,040 2015 — — — — — — — — 20,084 31,850 2016 — — — — — — — — — 43,793 Total $ 1,813,145 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 91 Adjustment for unallocated claim expenses 3,002 Reserve for losses and loss expenses, net of reinsurance $ 170,425 6. Reserve for losses and loss expenses, cont'd. Reinsurance Segment - Property Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 123,502 $ 137,474 $ 127,294 $ 120,598 $ 116,552 $ 115,947 $ 119,773 $ 121,653 $ 121,902 $ 117,706 $ 2 309 2008 — 173,437 151,764 133,022 123,162 124,861 126,887 126,991 125,622 122,943 3 612 2009 — — 151,371 123,151 116,114 114,137 114,342 115,111 115,213 111,782 114 991 2010 — — — 221,480 216,726 190,322 186,817 188,516 188,304 174,952 419 1,126 2011 — — — — 344,015 334,865 312,365 312,278 305,567 335,228 2,089 942 2012 — — — — — 314,924 259,753 240,928 240,070 244,651 2,224 813 2013 — — — — — — 255,632 239,844 217,661 199,195 5,650 1,017 2014 — — — — — — — 211,769 211,888 197,761 11,702 1,060 2015 — — — — — — — — 184,586 181,761 16,927 880 2016 — — — — — — — — — 166,629 55,289 542 Total $ 1,852,608 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 23,678 $ 71,828 $ 103,059 $ 111,825 $ 111,155 $ 112,559 $ 116,499 $ 119,203 $ 120,881 $ 116,680 2008 — 30,553 79,457 104,279 107,291 110,039 118,745 122,512 123,954 121,472 2009 — — 27,690 71,123 89,940 97,377 103,688 107,021 109,796 107,609 2010 — — — 49,442 117,260 141,348 163,173 175,919 180,555 170,367 2011 — — — — 76,880 172,679 254,657 286,065 291,961 326,570 2012 — — — — — 53,488 146,671 192,022 214,711 230,684 2013 — — — — — — 55,668 138,841 173,888 176,721 2014 — — — — — — — 51,635 134,663 158,766 2015 — — — — — — — — 37,685 100,328 2016 — — — — — — — — — 33,787 Total $ 1,542,984 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 4,954 Adjustment for unallocated claim expenses 4,301 Reserve for losses and loss expenses, net of reinsurance $ 318,879 6. Reserve for losses and loss expenses, cont'd. Reinsurance Segment - Casualty Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 108,468 $ 116,074 $ 116,095 $ 120,815 $ 115,024 $ 114,484 $ 112,945 $ 111,664 $ 110,369 $ 112,366 $ 13,382 549 2008 — 112,680 118,736 116,204 114,790 107,336 101,613 98,504 97,260 93,732 9,538 406 2009 — — 116,515 126,969 124,218 127,972 126,505 121,969 115,317 114,901 20,438 433 2010 — — — 186,667 179,891 176,073 170,938 172,699 160,142 159,409 27,794 506 2011 — — — — 198,159 199,035 197,138 204,187 195,094 196,946 35,929 604 2012 — — — — — 195,983 191,436 193,164 183,512 174,625 42,134 701 2013 — — — — — — 178,401 172,604 170,144 163,986 62,188 842 2014 — — — — — — — 125,515 120,521 119,143 45,271 615 2015 — — — — — — — — 119,276 119,529 58,182 250 2016 — — — — — — — — — 143,263 106,858 127 Total $ 1,397,900 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 3,009 $ 13,399 $ 23,890 $ 35,928 $ 48,519 $ 57,254 $ 64,711 $ 73,518 $ 77,378 $ 87,170 2008 — 8,475 17,338 30,528 43,923 51,831 58,419 67,856 72,592 75,906 2009 — — 7,367 21,841 34,770 51,576 61,615 70,558 76,463 83,892 2010 — — — 14,826 34,469 56,997 75,290 92,382 104,037 114,875 2011 — — — — 28,035 50,998 77,748 104,394 116,519 141,449 2012 — — — — — 30,667 54,457 75,456 92,072 105,209 2013 — — — — — — 18,577 35,808 56,564 71,677 2014 — — — — — — — 10,390 33,215 49,951 2015 — — — — — — — — 15,817 34,396 2016 — — — — — — — — — 18,837 Total $ 783,362 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 106,483 Adjustment for unallocated claim expenses 10,637 Reserve for losses and loss expenses, net of reinsurance $ 731,658 6. Reserve for losses and loss expenses, cont'd. Reinsurance Segment - Professional Lines Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 46,031 $ 51,283 $ 49,539 $ 43,988 $ 41,956 $ 41,037 $ 43,261 $ 42,115 $ 41,989 $ 37,980 $ 1,539 310 2008 — 41,797 50,276 47,154 44,672 47,084 44,526 42,863 41,599 39,059 1,171 262 2009 — — 41,430 43,003 41,681 40,763 35,771 36,560 36,474 38,720 2,098 204 2010 — — — 58,153 58,567 67,335 62,185 53,825 46,661 45,024 3,733 110 2011 — — — — 55,812 56,535 55,286 44,921 36,691 31,390 4,828 57 2012 — — — — — 43,519 42,443 43,426 36,707 30,576 5,803 81 2013 — — — — — — 48,933 49,513 45,382 41,403 21,619 48 2014 — — — — — — — 91,943 88,915 90,713 50,367 62 2015 — — — — — — — — 130,595 130,832 99,261 55 2016 — — — — — — — — — 148,671 139,857 10 Total $ 634,368 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 144 $ 2,310 $ 5,649 $ 10,694 $ 16,764 $ 21,259 $ 28,121 $ 30,796 $ 33,144 $ 32,771 2008 — 341 2,156 6,200 12,752 22,496 26,811 30,169 32,873 33,434 2009 — — 1,033 3,330 7,963 15,666 19,184 23,469 27,039 32,329 2010 — — — 2,249 7,348 14,481 24,511 31,313 36,100 36,181 2011 — — — — 1,685 4,943 9,405 15,168 20,124 22,142 2012 — — — — — 965 1,929 4,204 9,147 13,757 2013 — — — — — — 997 2,561 6,694 11,636 2014 — — — — — — — 1,149 6,446 22,822 2015 — — — — — — — — 2,941 14,357 2016 — — — — — — — — — 1,920 Total $ 221,349 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 5,540 Adjustment for unallocated claim expenses 6,164 Reserve for losses and loss expenses, net of reinsurance $ 424,723 6. Reserve for losses and loss expenses, cont'd. Reinsurance Segment - Specialty Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 229,505 $ 202,655 $ 197,905 $ 193,084 $ 189,577 $ 187,961 $ 187,949 $ 185,743 $ 183,044 $ 174,205 $ 435 288 2008 — 125,389 94,050 92,039 79,903 79,052 77,556 75,348 73,745 67,604 3,549 195 2009 — — 98,431 81,269 73,387 69,691 67,605 65,333 62,834 62,501 4,414 170 2010 — — — 123,741 107,630 97,718 86,949 85,252 84,817 82,937 1,856 218 2011 — — — — 111,517 100,639 86,832 82,514 82,984 82,014 2,565 274 2012 — — — — — 135,448 111,813 99,700 92,162 85,852 5,174 294 2013 — — — — — — 103,014 93,335 92,119 83,806 9,865 329 2014 — — — — — — — 120,335 116,642 108,392 19,693 342 2015 — — — — — — — — 150,288 149,473 35,118 318 2016 — — — — — — — — — 156,042 111,660 134 Total $ 1,052,826 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 16,023 $ 123,632 $ 143,800 $ 153,622 $ 160,113 $ 169,797 $ 174,059 $ 175,948 $ 177,082 $ 169,673 2008 — 15,525 38,261 47,410 52,461 58,971 61,915 64,489 65,005 61,384 2009 — — 13,286 33,142 39,439 43,804 47,556 52,481 52,635 55,068 2010 — — — 15,110 48,043 57,822 64,199 68,915 72,072 74,797 2011 — — — — 22,755 44,494 61,019 68,869 73,730 75,760 2012 — — — — — 29,756 53,695 64,242 72,510 74,517 2013 — — — — — — 14,696 37,621 52,015 62,458 2014 — — — — — — — 23,579 49,847 66,813 2015 — — — — — — — — 18,994 70,659 2016 — — — — — — — — — 19,265 Total $ 730,394 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 24,265 Adjustment for unallocated claim expenses 6,119 Reserve for losses and loss expenses, net of reinsurance $ 352,816 6. Reserve for losses and loss expenses, cont'd. Reconciliation of Claims Development Tables to Gross Reserve for Losses and Loss Expenses The following is a reconciliation of the net incurred and paid claims development tables to the reserve for losses and loss expenses in the consolidated balance sheet at December 31, 2016 . December 31, 2016 Net reserve for losses and loss expenses Reinsurance recoverable on unpaid losses Gross reserve for losses and loss expenses Insurance Agriculture $ 131,055 $ 116,832 $ 247,887 Casualty & other specialty 881,797 490,447 1,372,244 Professional lines 406,260 305,114 711,374 Property, marine/energy & aviation 274,396 193,088 467,484 Reinsurance Catastrophe 170,425 39,419 209,844 Property 318,879 1,466 320,345 Casualty 731,658 1,175 732,833 Professional lines 424,723 449 425,172 Specialty 352,816 65,139 417,955 Total $ 3,692,009 $ 1,213,129 $ 4,905,138 Historical Claims Duration The following is unaudited supplementary information about historical average claims duration by line of business. Average annual percentage payout of incurred claims by age, net of reinsurance (number of years) 1 2 3 4 5 6 7 8 9 10 Insurance Segment Agriculture 73.3 % 24.1 % 0.1 % 0.3 % — % — % — % — % — % — % Casualty & other specialty 5.5 % 11.3 % 15.5 % 15.1 % 12.8 % 7.1 % 4.5 % 2.7 % 3.7 % 1.4 % Professional lines 1.5 % 7.8 % 11.0 % 14.3 % 15.0 % 14.4 % 10.3 % 8.9 % 8.3 % 7.2 % Property, marine/energy & aviation 24.4 % 39.3 % 18.0 % 9.9 % 4.3 % 2.1 % 3.2 % 0.4 % 1.1 % 0.2 % Reinsurance Segment Catastrophe 32.4 % 36.1 % 15.4 % 7.6 % 3.4 % 1.7 % 0.2 % 0.3 % 1.3 % 1.0 % Property 24.1 % 39.4 % 19.5 % 6.5 % 3.5 % 2.7 % 0.5 % 0.9 % 0.9 % 0.3 % Casualty 9.2 % 12.6 % 12.7 % 11.9 % 9.9 % 8.2 % 6.3 % 5.5 % 4.4 % 3.2 % Professional lines 1.9 % 6.7 % 12.1 % 18.5 % 16.9 % 12.2 % 8.2 % 6.4 % 4.3 % 3.3 % Specialty 13.9 % 37.7 % 20.6 % 7.0 % 7.6 % 4.6 % 2.2 % 3.1 % 0.6 % — %

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2016
Reinsurance Disclosures [Abstract]
Reinsurance	7. Reinsurance The effects of reinsurance on premiums earned and written during the years ended December 31, 2016 , 2015 and 2014 are as follows: Year Ended December 31, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Earned Written Earned Written Earned Written Direct $ 2,336,314 $ 2,570,494 $ 1,938,830 $ 2,085,901 $ 1,521,648 $ 1,716,128 Assumed 1,635,379 1,631,676 1,331,831 1,234,960 1,132,370 1,177,948 Ceded (1,608,033 ) (1,832,235 ) (1,292,208 ) (1,370,391 ) (790,040 ) (959,870 ) $ 2,363,660 $ 2,369,935 $ 1,978,453 $ 1,950,470 $ 1,863,978 $ 1,934,206 The Company purchases reinsurance to reduce its exposure to risk of loss in certain insurance and reinsurance lines of business. Reinsurance recoverables are recorded as assets if the reinsurer is deemed able to meet its obligations. Ceded reinsurance contracts do not relieve the Company from its obligations to policyholders. The Company remains primarily liable to its policyholders for the portion reinsured to the extent that any reinsurer does not meet the obligations assumed under the reinsurance agreements. During the year ended December 31, 2016 , the Company recorded ceded losses of $824.3 million ( 2015 - $ 833.7 million; 2014 - $ 575.7 million). The balance of reinsurance recoverable on paid and unpaid losses at December 31, 2016 and 2015 was distributed as follows based on the ratings of the reinsurers: Rating December 31, 2016 December 31, 2015 U.S. Government sponsored program $ 141,443 $ 234,596 A+ and above 889,814 458,255 A 397,691 476,184 A- 5,805 7,060 Not rated 52,165 19,875 Total $ 1,486,918 $ 1,195,970 At December 31, 2016 and 2015 , the Company held collateral of $ 493.3 million and $ 321.5 million, respectively, related to its ceded reinsurance agreements.

Debt And Financing Arrangements

Debt And Financing Arrangements	12 Months Ended
	Dec. 31, 2016
Debt Instruments [Abstract]
Debt And Financing Arrangements	8. Debt and financing arrangements Credit Facility On March 23, 2016, the Company and certain designated subsidiaries of the Company entered into a $450.0 million five -year letter of credit facility with JPMorgan Chase Bank, N.A. ("JPMorgan") as administrative agent (the "Credit Facility"). Upon entering into the Credit Facility, the Company terminated its existing $700.0 million credit agreement, dated April 19, 2012, with JPMorgan as administrative agent. The Credit Facility does not provide for revolving or term loans. As of December 31, 2016 and 2015 , there were no borrowings under the Credit Facility and letters of credit outstanding under the Credit Facility were $199.8 million ( 2015 - $329.9 million ). The Credit Facility is collateralized on a several basis by each entity incurring such obligation by cash and securities deposited into collateral accounts from time to time with Deutsche Bank Trust Company Americas as collateral agent. So long as there is no default under the terms of the Credit Facility, the Company may request that the size of the Credit Facility be increased by $100.0 million , but no participating lender is obligated to increase its commitments under the Credit Facility. 8. Debt and financing arrangements, cont'd. The Company is required to pay a fee of 0.40% per annum on the daily stated amount of outstanding letters of credit issued under the Credit Facility. In addition, the Credit Facility requires the Company to pay to the lenders a commitment fee of 0.125% per annum on the average daily amount of the unused commitments of the lenders. The Credit Facility permits a lender, if requested and in its discretion, to issue a letter of credit pursuant to which it fronts for the other lenders. For such letters of credit, such fronting lenders may receive certain fronting fees from the Company. The Credit Facility requires the Company's compliance with certain customary restrictive covenants, including a financial covenant that the Company maintain a leverage ratio of no greater than 0.35 :1.00 at any time. In addition, each of the Company's regulated insurance subsidiaries that has a claims paying rating from A.M. Best must maintain a rating of at least "B+" at all times. The Credit Facility also contains customary event of default provisions, including failure to pay any unpaid drawing under a letter of credit under the Credit Facility or interest thereon and failure to pay any fee under the Credit Facility, insolvency events of the Company or any of its subsidiaries (other than certain immaterial subsidiaries), a change in control of the Company, a breach of the representations or covenants in the Credit Facility or the security documents relating thereto and certain defaults by the Company or its subsidiaries under other indebtedness. In the case of an event of default that occurs as a result of an insolvency event of the Company or one of its designated subsidiary borrowers, the commitments of the lenders will automatically terminate and the repayment of outstanding obligations will be automatically accelerated. Upon the occurrence of any other event of default under the Credit Facility, the lenders can terminate their commitments under the Credit Facility, require repayment of any outstanding obligations under the Credit Facility, give notice of non-extension of any outstanding letters of credit in accordance with their terms, require the delivery of cash collateral for outstanding letters of credit and foreclose on any collateral held by the lenders (or any agent on their behalf) under the Credit Facility. Uncommitted Letter of Credit Agreements The Company is party to certain uncommitted letter of credit reimbursement agreements ("LOC Agreements") that allow for the issuance of letters of credit in a variety of currencies, including U.S. dollars. The fees paid under the LOC Agreements depend on the amount of the outstanding letters of credit and vary from 0.30% to 0.45% on the principal amount of letters of credit outstanding to a fee negotiated at the time of issuance of the individual letters of credit. The total amount of letters of credit outstanding under the LOC Agreements at December 31, 2016 was $22.5 million ( December 31, 2015 - $11.7 million ). 7% Senior Notes The Company issued $335.0 million principal amount of 7% Senior Notes due July 15, 2034 (the "7% Senior Notes"). The 7% Senior Notes are senior unsecured obligations of Endurance Holdings and rank equally with all of Endurance Holdings' existing and future unsecured and unsubordinated debt. The 7% Senior Notes are also effectively junior to claims of creditors of Endurance Holdings' subsidiaries, including policyholders, trade creditors, debt holders, and taxing authorities. The indentures governing the 7% Senior Notes contain customary covenants and events of default for senior unsecured indebtedness, including events of default for non-payment of principal or interest, breaches of covenants, insolvency of the Company or a default by the Company under other outstanding indebtedness. The Company was in compliance with all covenants contained within the indentures governing the 7% Senior Notes as of December 31, 2016 and 2015 . 6.15% Senior Notes The Company issued $200.0 million principal amount of 6.15% Senior Notes due 2015 (the "6.15% Senior Notes"). The 6.15% Senior Notes were senior unsecured obligations of Endurance Holdings and ranked equally with all of Endurance Holdings' existing and future unsecured and unsubordinated debt. The 6.15% Senior Notes also were effectively junior to claims of creditors of Endurance Holdings' subsidiaries, including policyholders, trade creditors, debt holders, and taxing authorities. The 6.15% Senior Notes matured on October 15, 2015 and were repaid by the Company on that date. 8. Debt and financing arrangements, cont'd. 4.7% Senior Notes Upon closing of the acquisition of Montpelier, Montpelier, as issuer, Endurance Holdings, as parent guarantor, and The Bank of New York Mellon, as trustee, entered into a Fourth Supplemental Indenture, dated as of July 31, 2015 (the "Fourth Supplemental Indenture"). The Fourth Supplemental Indenture amended the Indenture, dated as of July 15, 2003 (as amended and supplemented from time to time (collectively, the "Senior Notes Supplemental Indentures")) applicable to the 4.7% Senior Unsecured Notes Due 2022 (the "4.7% Senior Notes") originally issued by Montpelier on October 2, 2012 in an aggregate principal amount of $300.0 million . The Senior Notes Supplemental Indentures provided for the unconditional assumption of the due and punctual payment of the principal of, any premium and interest on and any additional amounts with respect to the 4.7% Senior Notes and the performance of every obligation in the Senior Notes Indenture and the 4.7% Senior Notes to be performed or observed. The 4.7% Senior Notes bear a rate of interest equal to 4.7% per annum, payable semi-annually in arrears on April 15 and October 15 each year. The 4.7% Senior Notes mature on October 15, 2022. The 4.7% Senior Notes do not contain any covenants regarding financial ratios or specified levels of net worth or liquidity to which the Company or any of its subsidiaries must adhere but do contain customary covenants and events of default for senior unsecured indebtedness, including events of default for non-payment of principal or interest, breaches of covenants, insolvency of the Company or a default by the Company under other outstanding indebtedness. The Company was in compliance with all covenants contained within the indentures governing the 4.7% Senior Notes as of December 31, 2016 and 2015 . The 4.7% Senior Notes are senior unsecured obligations of Endurance Holdings and rank equally with all of Endurance Holdings' existing and future unsecured and unsubordinated debt. The 4.7% Senior Notes are also effectively junior to claims of creditors of Endurance Holdings' subsidiaries, including policyholders, trade creditors, debt holders, and taxing authorities. Trust Preferred Securities Upon closing the acquisition of Montpelier, Montpelier, as issuer, Endurance Holdings, as parent guarantor, and Wilmington Trust Company, as trustee, entered into the Second Supplemental Indenture, dated as of July 31, 2015 (the "Second Supplemental Indenture"). The Second Supplemental Indenture amended the Junior Subordinated Indenture, dated as of January 6, 2006 (as amended and supplemented from time to time (collectively, the "Junior Subordinated Supplemental Indentures")). The Junior Subordinated Supplemental Indentures provided for the express assumption by Endurance Holdings of the due and punctual payment of the principal of and any premium and interest (including any additional interest) on the unsecured junior subordinated deferrable interest notes issued by Montpelier in connection with the issuance of the trust preferred securities (the "Trust Preferred Securities") by MRH Capital Trust III (the "MRH Capital Trust") and the performance of every covenant of the Junior Subordinated Indenture on the part of Montpelier to be performed or observed. The MRH Capital Trust originally issued the Trust Preferred Securities in January 2006 in an aggregate principal amount of $100.0 million . The Trust Preferred Securities mature on March 30, 2036 and bear interest at a floating rate of 3-month LIBOR plus 380 basis points, reset quarterly. The Trust Preferred Securities may be redeemed prior to maturity at a redemption price equal to 100% of the principal amount thereof plus accrued interest, provided that the prior approval of any applicable insurance regulatory authority with respect to such redemption has been received. The Trust Preferred Securities do not contain any covenants regarding financial ratios or specified levels of net worth or liquidity to which the Company or any of its subsidiaries must adhere. LIBOR Swap Upon closing of the acquisition of Montpelier, the Company became a party to the LIBOR Swap, which will result in the future net cash flows in connection with the Trust Preferred Securities for the 5 -year period beginning March 30, 2012 being the same as if these securities bore interest at a fixed rate of 4.905% , provided the Company holds the LIBOR Swap to its maturity. Net realized and unrealized gains and losses associated with the LIBOR Swap are reported within net realized and unrealized gains on the Company's Consolidated Statements of Income and Comprehensive Income, as opposed to interest expense. Interest Payments The Company made aggregate interest payments of $42.7 million during the year ended December 31, 2016 ( 2015 - $40.5 million ; 2014 - $40.4 million ). 8. Debt and financing arrangements, cont'd. BCRH Credit Agreement On May 6, 2016, the Company, through a wholly-owned subsidiary, entered into a credit facility agreement with BCRH (the "BCRH Credit Facility"). The BCRH Credit Facility provides BCRH with an unsecured $20.0 million revolving credit facility for working capital and general corporate purposes and expires on September 30, 2018. Borrowings under the BCRH Credit Facility bear interest, set at the time of the borrowing, at a rate equal to the applicable LIBOR rate plus 150 basis points. The BCRH Credit Facility contains covenants that limit BCRH's ability, among other things, to grant liens on its assets, sell assets, merge or consolidate, or incur debt. If BCRH fails to comply with any of these covenants, the Company could terminate the BCRH Credit Facility and exercise remedies against BCRH. In addition, in the event of a default in the performance of any of the agreements or covenants under certain management agreements with BCML by BCRH, the Company has the right to terminate the BCRH Credit Facility. As of December 31, 2016 , BCRH had no outstanding borrowings under the BCRH Credit Facility. BCGR Credit Agreement On May 16, 2016, the Company, through a wholly-owned subsidiary, entered into a credit facility agreement with BCGR (the "BCGR Credit Facility"). The BCGR Credit Facility provides BCGR with an unsecured $20.0 million revolving credit facility for working capital and general corporate purposes and expires on September 30, 2018. Borrowings under the BCGR Credit Facility bear interest, set at the time of the borrowing, at a rate equal to the applicable LIBOR rate plus 150 basis points. The BCGR Credit Facility contains covenants that limit BCGR's ability, among other things, to grant liens on its assets, sell assets, merge or consolidate, or incur debt. If BCGR fails to comply with any of these covenants, the Company could terminate the BCGR Credit Facility and exercise remedies against BCGR. In addition, in the event of a default in the performance of any of the agreements or covenants under certain management agreements with BCML by BCGR, the Company has the right to terminate the BCGR Credit Facility. As of December 31, 2016 , BCGR had no outstanding borrowings under the BCGR Credit Facility.

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	9. Derivatives In 2004, prior to the issuance of the 7% Senior Notes, the Company entered into an interest rate lock on a notional amount of $125.0 million to protect against interest rate increases before the anticipated issuance of the Senior Notes. The objective of the interest rate lock was to protect 50% of the forecasted receipt of proceeds from the issuance of the 7% Senior Notes offering, which was subject to change prior to issuance due to fluctuations in the benchmark 30 year U. S. Treasury rate. Upon issuance of the 7% Senior Notes, the interest rate lock was settled through payment by the Company of $2.7 million . The interest rate lock agreement was designated as a "cash flow hedge" under current accounting guidance and accordingly, the fair value of the derivative was recorded in other comprehensive (loss) income and is being recognized as a component of interest expense in the Consolidated Statements of Income and Comprehensive Income as the interest expense related to the 7% Senior Notes affects earnings. The net income effect of the interest rate lock was not material. 9. Derivatives, cont'd. The Company regularly transacts in certain derivative-based weather risk management products primarily to address weather and energy risks on behalf of third parties. The markets for these derivatives are generally linked to energy and agriculture commodities, weather and other natural phenomena. Generally, the Company's current portfolio of such derivative contracts is of short duration and such contracts are predominantly seasonal in nature. The Company also invests a portion of its investments with third party investment managers with investment guidelines that permit the use of derivative instruments. The Company may enter derivative transactions directly or as part of strategies employed by its external investment managers. None of the Company's derivatives are designated as hedges under current accounting guidance, with the exception of the interest rate lock. The Company's objectives for holding these derivatives are as follows: Interest Rate Futures, Swaps, Swaptions and Options - to manage exposure to interest rate risk, which can include increasing or decreasing its exposure to this risk through modification of the portfolio composition and duration. Industry Loss Warranty ("ILW") Swaps - to manage underwriting risk. The Company has entered into ILW swap contracts which provide reinsurance-like protection to the Company for specific loss events associated with certain lines of its business. The Company has also sold ILW protection, which provides reinsurance-like protection to third parties for specific loss events. Foreign Exchange Forwards, Futures and Options - as part of its overall currency risk management and investment strategies. Credit Default Swaps - to manage market exposures. The Company may assume or economically hedge credit risk through credit default swaps to replicate or hedge investment positions. The original term of these credit default swaps is generally five years or less. To-Be-Announced Mortgage-backed Securities (“TBAs”) - to enhance investment performance and as part of the overall investment strategy. TBAs represent commitments to purchase or sell a future issuance of agency mortgage-backed securities. For the period between the purchase of a TBA and issuance of the underlying securities, the Company’s position is accounted for as a derivative. Energy and Weather Contracts - to address weather and energy risks. The Company may purchase or sell contracts with financial settlements based on the performance of an index linked to a quantifiable weather element, such as temperature, precipitation, snowfall or windspeed, and structures with multiple risk triggers indexed to a quantifiable weather element and a weather sensitive commodity price, such as temperature and electrical power or natural gas. Generally, the Company’s current portfolio of energy and weather derivative contracts is of comparably short duration and such contracts are predominantly seasonal in nature. LIBOR Swap – to establish future net cash flows in connection with the Trust Preferred Securities for the 5 -year period beginning March 30, 2012 as if these securities bore interest at a fixed rate of 4.905% . See Note 8, Debt and financing arrangements. Loss Development Cover – as part of the sale of Montpelier U.S. Insurance Company ("MUSIC") to Selective Insurance Group, Inc. ("Selective"), Montpelier Reinsurance Ltd. ("Montpelier Re", now Endurance Bermuda) entered into a loss development cover with MUSIC which ensures that MUSIC's reserve for losses and loss expenses relating to retained business written on or prior to December 31, 2011 remains adequate. Under the loss development cover, any future adverse development associated with such retained reserves will be protected by Endurance Bermuda and any future favorable development associated with such retained reserves will benefit Endurance Bermuda. 9. Derivatives, cont'd. The fair values and the related notional values of derivatives at December 31, 2016 and 2015 are noted below. December 31, 2016 December 31, 2015 Fair Value Notional Principal Amount Fair Value Notional Principal Amount Derivatives recorded in other assets Foreign exchange forward contracts $ 629 $ 34,630 $ 425 $ 38,818 Credit default swaps 266 5,450 36 4,225 Interest rate swaps 374 7,000 — — ILWs 1,010 20,000 — — TBAs 121,402 120,300 26,924 25,700 Energy and weather contracts 43,035 101,436 41,507 70,388 Total recorded in other assets $ 166,716 $ 68,892 Derivatives recorded in other liabilities Foreign exchange forward contracts $ 1,204 $ 32,080 $ 372 $ 30,400 Credit default swaps 21 2,744 276 7,800 Interest rate swaps 59 1,100 7 42,000 Interest rate swaptions 34 5,400 — — Interest rate futures — — 8 54,488 ILWs 184 14,209 259 19,500 LIBOR swap 27 100,000 233 100,000 TBAs 50,704 50,400 — — Loss development cover 2,818 24,451 2,904 22,322 Energy and weather contracts 29,018 162,900 42,029 148,325 Total recorded in other liabilities $ 84,069 $ 46,088 Net derivative asset $ 82,647 $ 22,804 At December 31, 2016 , derivative assets of $166.7 million (December 31, 2015 - $68.9 million ) and liabilities of $84.1 million (December 31, 2015 - $46.1 million ) were subject to master netting agreements, which provide for the ability to settle the derivative asset and liability with each counterparty on a net basis. Interest rate futures are not subject to master netting agreements. At December 31, 2016 and 2015 , the Company's derivative instruments were recorded on a gross basis in the Consolidated Balance Sheets. At December 31, 2016 , the Company held no reverse repurchase agreements ( December 31, 2015 - $30.0 million ). These loans are fully collateralized, are generally outstanding for a short period of time and are presented as part of cash and cash equivalents in the Consolidated Balance Sheets. The required collateral for these loans is either cash or U.S. treasury securities at a minimum rate of 102% of the loan principal. Upon maturity, the Company receives principal and interest income. 9. Derivatives, cont'd. The gains and losses on the Consolidated Statements of Income and Comprehensive Income for derivatives for the years ended December 31, 2016 , 2015 and 2014 were as follows: 2016 2015 2014 Total gain included in net foreign exchange (gains) losses from foreign exchange forward contracts $ 516 $ 2,095 $ 1,880 Interest rate futures (160 ) 79 121 Credit default swaps 7 (50 ) 30 Interest rate swaps 124 (915 ) (4,239 ) Interest rate swaptions (20 ) 56 477 ILWs (1,675 ) (326 ) — LIBOR swap 206 332 — TBAs (662 ) 496 3,938 Total (losses) gains included in net realized and unrealized (losses) gains (2,180 ) (328 ) 327 Energy and weather contracts 4,835 2,281 (315 ) Loss development cover (2,129 ) (1,419 ) — Total gain (loss) included in other underwriting loss 2,706 862 (315 ) Total gains from derivatives $ 1,042 $ 2,629 $ 1,892

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment Reporting	10. Segment reporting The determination of the Company's business segments is based on how the Company monitors the performance of its underwriting operations. The Company has two reportable business segments, Insurance and Reinsurance. • Insurance – This segment is comprised of four lines of business: agriculture, casualty and other specialty, professional lines, and property, marine/energy and aviation. The agriculture line of business is comprised of multi-peril crop insurance, crop hail, livestock risk protection and other agriculture risk management products. The casualty and other specialty line of business is comprised of the insurance and facultative reinsurance of third party liability exposures, including casualty and healthcare liability. The professional line of business includes directors' and officers' liability, errors and omissions, employment practices liability, environmental liability and pension trust liability insurance. The property, marine/energy and aviation line of business is comprised of the insurance and facultative reinsurance of commercial properties, inland marine and ocean marine insurance, energy insurance, and general liability and property coverages for a wide range of general aviation risks. • Reinsurance – This segment is comprised of five lines of business: catastrophe, property, casualty, professional lines, and specialty. The catastrophe line of business includes reinsurance for catastrophic perils on a treaty basis. The property line of business includes proportional and excess of loss reinsurance of personal and commercial exposures. The casualty line of business is comprised of third party liability exposures, clash and workers' compensation coverages. The professional line of business includes directors' and officers' liability, errors and omissions, employment practices liability, environmental liability and pension trust liability reinsurance. The specialty line of business includes the reinsurance of aviation and space business and proportional and non-proportional reinsurance of hull and cargo insurance business, and proportional and excess of loss coverages of contract and commercial surety business, personal accident coverages, political risk coverages, weather risk management products and agriculture coverages for weather related perils as well as protection from yield and price risks. 10. Segment reporting, cont'd. Management measures Insurance and Reinsurance segment results on the basis of the combined ratio, which is obtained by dividing the sum of the net losses and loss expenses, acquisition expenses and general and administrative expenses by net premiums earned. When purchased within a single line of business, ceded reinsurance and recoveries are accounted for within that line of business. When purchased across multiple lines of business, ceded reinsurance and recoveries are allocated to the lines of business in proportion to the related risks assumed. The Company does not manage its assets by segment; accordingly, investment income and total assets are not allocated to the individual business segments. General and administrative expenses incurred by segments are allocated directly. Remaining general and administrative expenses not incurred by the segments are classified as corporate expenses and are not allocated to the individual business segments. Ceded reinsurance and recoveries are recorded within the business segment to which they apply. The underwriting results of Montpelier are included in the Company's segment results from August 1, 2015. The following table provides a summary of the segment revenues and results for the year ended December 31, 2016 , reserve for losses and loss expenses as of December 31, 2016 and the carrying value of goodwill as of December 31, 2016 : Insurance Reinsurance Total Revenues Gross premiums written $ 2,570,494 $ 1,631,676 $ 4,202,170 Ceded premiums written (1,514,240 ) (317,995 ) (1,832,235 ) Net premiums written 1,056,254 1,313,681 2,369,935 Net premiums earned 1,009,375 1,354,285 2,363,660 Other underwriting loss — (909 ) (909 ) 1,009,375 1,353,376 2,362,751 Expenses Net losses and loss expenses 684,178 636,874 1,321,052 Acquisition expenses 149,763 310,720 460,483 General and administrative expenses 140,742 107,404 248,146 974,683 1,054,998 2,029,681 Underwriting income $ 34,692 $ 298,378 333,070 Net investment income 176,590 Corporate expenses (51,706 ) Net foreign exchange gains 74,684 Net realized and unrealized losses (12,419 ) Net impairment losses recognized in earnings (10,769 ) Amortization of intangibles (84,624 ) Interest expense (43,860 ) Income before income taxes $ 380,966 Net loss ratio 67.9 % 47.1 % 55.9 % Acquisition expense ratio 14.8 % 22.9 % 19.5 % General and administrative expense ratio 13.9 % 7.9 % 12.7 % (1) Combined ratio 96.6 % 77.9 % 88.1 % Reserve for losses and loss expenses $ 2,798,989 $ 2,106,149 $ 4,905,138 Goodwill $ 83,550 $ 91,932 $ 175,482 (1) Total general and administrative expense ratio includes general and administrative expenses and corporate expenses. 10. Segment reporting, cont'd. The following table provides a summary of the segment revenues and results for the year ended December 31, 2015 , reserve for losses and loss expenses as of December 31, 2015 and the carrying value of goodwill as of December 31, 2015 : Insurance Reinsurance Total Revenues Gross premiums written $ 2,085,901 $ 1,234,960 $ 3,320,861 Ceded premiums written (1,205,528 ) (164,863 ) (1,370,391 ) Net premiums written 880,373 1,070,097 1,950,470 Net premiums earned 824,552 1,153,901 1,978,453 Other underwriting loss — (3,694 ) (3,694 ) 824,552 1,150,207 1,974,759 Expenses Net losses and loss expenses 500,867 416,241 917,108 Acquisition expenses 80,252 267,633 347,885 General and administrative expenses 140,012 119,779 259,791 721,131 803,653 1,524,784 Underwriting income $ 103,421 $ 346,554 449,975 Net investment income 113,826 Corporate expenses (114,429 ) Net foreign exchange losses (26,964 ) Net realized and unrealized gains 12,660 Net impairment losses recognized in earnings (3,715 ) Amortization of intangibles (30,620 ) Interest expense (41,260 ) Income before income taxes $ 359,473 Net loss ratio 60.8 % 36.0 % 46.4 % Acquisition expense ratio 9.7 % 23.2 % 17.6 % General and administrative expense ratio 17.0 % 10.4 % 18.9 % (1) Combined ratio 87.5 % 69.6 % 82.9 % Reserve for losses and loss expenses $ 2,493,894 $ 2,016,521 $ 4,510,415 Goodwill $ 84,525 $ 91,930 $ 176,455 (1) Total general and administrative expense ratio includes general and administrative expenses and corporate expenses. 10. Segment reporting, cont'd. The following table provides a summary of the segment revenues and results for the year ended December 31, 2014 , reserve for losses and loss expenses as of December 31, 2014 and the carrying value of goodwill as of December 31, 2014 : Insurance Reinsurance Total Revenues Gross premiums written $ 1,716,128 $ 1,177,948 $ 2,894,076 Ceded premiums written (855,722 ) (104,148 ) (959,870 ) Net premiums written 860,406 1,073,800 1,934,206 Net premiums earned 833,912 1,030,066 1,863,978 Other underwriting loss — (5,786 ) (5,786 ) 833,912 1,024,280 1,858,192 Expenses Net losses and loss expenses 594,561 375,601 970,162 Acquisition expenses 65,368 254,145 319,513 General and administrative expenses 148,475 98,912 247,387 808,404 728,658 1,537,062 Underwriting income $ 25,508 $ 295,622 321,130 Net investment income 131,543 Corporate expenses (66,200 ) Net foreign exchange losses (3,839 ) Net realized and unrealized gains 14,283 Net impairment losses recognized in earnings (625 ) Amortization of intangibles (6,484 ) Interest expense (40,968 ) Income before income taxes $ 348,840 Net loss ratio 71.4 % 36.4 % 52.1 % Acquisition expense ratio 7.8 % 24.7 % 17.1 % General and administrative expense ratio 17.7 % 9.6 % 16.8 % (1) Combined ratio 96.9 % 70.7 % 86.0 % Reserve for losses and loss expenses $ 2,123,772 $ 1,723,087 $ 3,846,859 Goodwill $ 47,925 $ 43,313 $ 91,238 (1) Total general and administrative expense ratio includes general and administrative expenses and corporate expenses. 10. Segment reporting, cont'd. The following table provides gross premiums written by line of business for the years ended December 31, 2016 , 2015 and 2014 : Business Segment 2016 2015 2014 Insurance Agriculture $ 760,877 $ 840,445 $ 866,025 Casualty and other specialty 657,558 514,203 396,113 Professional lines 461,552 344,482 263,538 Property, marine/energy and aviation 690,507 386,771 190,452 Total Insurance 2,570,494 2,085,901 1,716,128 Reinsurance Catastrophe 506,300 311,914 343,213 Property 250,447 209,392 287,326 Casualty 245,092 176,506 159,533 Professional lines 256,337 248,610 174,656 Specialty 373,500 288,538 213,220 Total Reinsurance 1,631,676 1,234,960 1,177,948 Total $ 4,202,170 $ 3,320,861 $ 2,894,076 The following table provides the geographic distribution of gross premiums written for the years ended December 31, 2016 , 2015 and 2014 : 2016 2015 2014 United States $ 2,823,950 $ 2,305,301 $ 2,054,431 Worldwide 794,289 566,664 456,078 Europe 265,100 209,729 172,077 Asia 105,838 75,165 38,442 Japan 82,864 58,524 45,618 Australasia 49,727 41,309 61,994 Other 80,402 64,169 65,436 Total $ 4,202,170 $ 3,320,861 $ 2,894,076 The Company attributes gross premiums written to the geographic region in which the risks originate.

Goodwill And Intangible Assets

Goodwill And Intangible Assets	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill And Intangible Assets	11. Goodwill and intangible assets The following table shows an analysis of goodwill and intangible assets for the years ended December 31, 2016 and 2015 : Goodwill Intangible assets with indefinite lives Intangible assets with finite lives Total Net balance at December 31, 2014 $ 91,238 $ 11,779 $ 50,388 $ 153,405 Additions (1) 87,367 57,600 293,218 438,185 Amortization — — (30,620 ) (30,620 ) Foreign currency translation (2,150 ) (2,738 ) (2,122 ) (7,010 ) Net balance at December 31, 2015 $ 176,455 $ 66,641 $ 310,864 $ 553,960 Additions (973 ) — 11 (962 ) Amortization — — (84,624 ) (84,624 ) Net balance at December 31, 2016 $ 175,482 $ 66,641 $ 226,251 $ 468,374 Gross balance $ 177,632 $ 74,829 $ 431,271 $ 683,732 Accumulated amortization — — (202,898 ) (202,898 ) Accumulated impairment losses — (5,450 ) — (5,450 ) Accumulated foreign currency translation (2,150 ) (2,738 ) (2,122 ) (7,010 ) Net balance $ 175,482 $ 66,641 $ 226,251 $ 468,374 (1) For additional information on the intangible assets acquired during 2015, see Note 3, Acquisition of Montpelier. For the years ended December 31, 2016 and 2015 , a valuation analysis was performed to determine the fair value of the Company's intangible assets with indefinite lives which showed that none of the Company's intangible assets were impaired. No impairment of the Company's goodwill asset was noted following the annual impairment reviews during the years ended December 31, 2016 and 2015 . The Company expects the amortization of the intangible assets with finite lives to approximate $63.7 million in 2017 , $37.7 million in 2018 , $27.5 million in 2019 , $22.8 million in 2020 , $21.6 million in 2021 and $53.0 million in all years thereafter.

Commitments And Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	12. Commitments and contingencies Concentrations of credit risk. The areas where significant concentrations of credit risk may exist include reinsurance recoverables, investments and cash and cash equivalents. The Company's reinsurance recoverables on paid and unpaid losses at December 31, 2016 and 2015 amounted to $1,486.9 million and $1,196.0 million , respectively, and resulted from reinsurance arrangements entered into in the normal course of operations. A credit exposure exists with respect to reinsurance recoverables as they may become uncollectible. The Company manages its credit risk in its reinsurance relationships by transacting with reinsurers that it considers financially sound and, if necessary, the Company may hold collateral in the form of cash, trust accounts and/or irrevocable letters of credit. This collateral can be drawn on for amounts that remain unpaid beyond specified time periods on an individual reinsurer basis. As of December 31, 2016 , $1,293.3 million of reinsurance recoverable on paid and unpaid losses ( 2015 - $941.5 million ) was due from reinsurers rated A- or better by A.M. Best or S&P. An additional $141.4 million ( 2015 - $234.6 million ) of reinsurance recoverable on paid and unpaid losses was due from a U.S. government sponsored reinsurance program as of December 31, 2016 . At December 31, 2016 and 2015 , the Company held collateral of $493.3 million and $321.5 million , respectively, related to its ceded reinsurance agreements. As of December 31, 2016 , substantially all the Company's cash and investments were held by six custodians. The Company's investment guidelines limit the amount of credit exposure to any one issuer other than the U.S. Treasury and certain other foreign government obligations rated AAA. 12. Commitments and contingencies, cont'd. Major production sources. The following table shows the percentage of gross premiums written generated through the Company's largest brokers for the years ended December 31, 2016 , 2015 and 2014 : Broker 2016 2015 2014 Marsh & McLennan Companies, Inc. 20.9 % 19.8 % 19.1 % Aon Benfield 14.3 % 12.8 % 13.2 % Willis Companies 8.9 % 9.2 % 10.6 % Total of largest brokers 44.1 % 41.8 % 42.9 % Letters of credit. As of December 31, 2016 , the Company had issued letters of credit of $222.3 million ( 2015 - $341.6 million ) under its credit facilities and letter of credit reimbursement agreements in favor of certain ceding companies to collateralize obligations. Investment commitments. As of December 31, 2016 and 2015 , the Company had pledged cash and cash equivalents and fixed maturity investments of $106.8 million and $108.9 million , respectively, in favor of certain ceding companies to collateralize obligations. As of December 31, 2016 and 2015 , the Company had also pledged $252.2 million and $383.3 million of its cash and fixed maturity investments as required to meet collateral obligations for $222.3 million and $341.6 million in secured letters of credit outstanding under its credit facilities, respectively. In addition, at December 31, 2016 and 2015 , cash and fixed maturity investments with fair values of $207.8 million and $208.3 million were on deposit with U.S. state regulators, respectively. The Company is subject to certain commitments with respect to other investments at December 31, 2016 and 2015 . See Note 4, Investments. Investment assets held in trust. Blue Water Re and Blue Water Re II do not operate with a financial strength rating and, instead, fully collateralizes their reinsurance obligations through cash and cash equivalents held in trust funds established by Blue Water Re and Blue Water Re II (the "Blue Water Trusts") for the benefit of ceding companies. As of December 31, 2016 , the fair value of assets held in the Blue Water Trusts was $427.8 million ( 2015 - $438.9 million ), which met the minimum values required on that date. As of December 31, 2016 , Blue Capital Re had pledged $191.4 million ( 2015 - $195.3 million ) of its cash and cash equivalents to trust accounts established for the benefit of Blue Water Re. Blue Capital Re ILS fully collateralizes its insurance-linked security obligations through cash and cash equivalents held in trust funds established by Blue Capital Re ILS (the "Blue Capital Re ILS Trusts") for the benefit of third parties. As of December 31, 2016 , the fair value of assets held in the Blue Capital Re ILS Trusts was $3.3 million ( 2015 - $5.2 million ), which met the minimum value required on that date. During 2015, Endurance Bermuda established a multi-beneficiary reinsurance trust (the "Endurance Reinsurance Trust") domiciled in Delaware. The Endurance Reinsurance Trust was established as a means of providing statutory credit to Endurance Bermuda's U.S. cedants. As of December 31, 2016 , the fair value of the assets held in the Endurance Reinsurance Trust exceeded $783.9 million ( 2015 - $94.1 million ), the minimum value required on that date. During 2015, Endurance Bermuda also established a second multi-beneficiary reinsurance trust (the "Reduced Collateral Trust") domiciled in Delaware. The Reduced Collateral Trust was established as a means of providing statutory credit to Endurance Bermuda's U.S. cedants in connection with a reduction in collateral requirements in certain states. As of December 31, 2016 , the fair value of the assets held in the Reduced Collateral Trust exceeded $16.4 million ( 2015 - $10.8 million ), the minimum value required on that date. Endurance Bermuda is party to a reinsurance trust (the "MUSIC Trust"). The MUSIC Trust was established as a means of providing statutory credit to MUSIC in support of the business retained in connection with the 2011 sale by Montpelier of MUSIC to Selective. As of December 31, 2016 , the fair value of the assets held in the MUSIC Trust was $24.6 million ( 2015 - $21.3 million ), the minimum value required on that date. 12. Commitments and contingencies, cont'd. Endurance Bermuda is party to a multi-beneficiary Reinsurance Trust originally established by Montpelier Re (the "Montpelier Reinsurance Trust") domiciled in New York. The Montpelier Reinsurance Trust was established as a means of providing statutory credit to Montpelier Re's U.S. cedants. Endurance Bermuda is also party to a multi-beneficiary reinsurance trust originally established by Montpelier Re (the "FL Trust") in connection with a reduction in its Florida collateral requirements. With the consent of the New York Department of Financial Services, all assets in excess of the statutory minimum required amounts in the Montpelier Reinsurance Trust and the FL Trust were transferred to the Endurance Reinsurance Trust and the Reduced Collateral Trust, respectively, upon the merger of Montpelier Re with and into Endurance Bermuda, with Endurance Bermuda as the surviving entity, on December 29, 2015. The Company is party to a Lloyd's Deposit Trust Deed (the "Lloyd's Capital Trust") in order to meet Endurance Corporate Capital Limited ("ECCL")'s ongoing funds at Lloyd's ("FAL") requirements. The minimum value of cash and investments held by the Lloyd’s Capital Trust is determined on the basis of ECCL's Individual Capital Assessment, which is used to determine the required amount of FAL. As of December 31, 2016 , the fair value of assets held in the Lloyd's Capital Trust was $323.6 million ( 2015 - $276.8 million ), which met the minimum value required on that date. Premiums received by Syndicate 5151 are required to be received into the Lloyd's Premiums Trust Funds (the "Premiums Trust Funds"). Under the Premiums Trust Funds' deeds, assets may only be used for the payment of claims and valid expenses for a stated period of time. As of December 31, 2016 , the fair value of assets held in the Premiums Trust Funds was $184.1 million ( 2015 - $231.9 million ). The Company's investment assets held in trust appear on the Company's Consolidated Balance Sheets as cash and cash equivalents, fixed maturity investments. short-term investments and accrued investment income, as appropriate. Lloyd's New Central Fund. The Lloyd's New Central Fund is available to satisfy claims if a member of Lloyd's is unable to meet its obligations to policyholders. The Lloyd's New Central Fund is funded by an annual levy imposed on members, which is determined annually by Lloyd's as a percentage of each member's gross written premiums ( 0.35% with respect to 2016 and 0.50% for 2015 ). In addition, the Council of Lloyd's has power to call on members to make an additional contribution to the Lloyd's New Central Fund of up to 3% of their underwriting capacity each year should it decide that such additional contributions are necessary. The Company currently estimates that its 2016 obligation to the Lloyd's New Central Fund will be approximately $1.1 million ( 2015 - $1.0 million ) and accrues for this obligation ratably throughout the year on a quarterly basis. Lloyd's also imposes other charges on its members and the syndicates on which they participate, including an annual subscription charge ( 0.45% of gross written premiums with respect to 2016 and 0.50% for 2015 ) and an overseas business charge, levied as a percentage of gross international premiums (defined as business outside the U.K. and the Channel Islands), with the percentage depending on the type of business written. Lloyd's also has power to impose additional charges under Lloyd's Powers of Charging Byelaw. The Company currently estimates that its 2016 obligation to Lloyd's for such charges will be approximately $1.4 million ( 2015 - $1.0 million ) and accrues for this obligation ratably throughout the year on a quarterly basis. Reinsurance commitments . In the ordinary course of business, the Company enters into reinsurance agreements that may include terms which could require the Company to collateralize certain of its obligations. Employment agreements. The Company has entered into employment agreements with certain officers that provide for equity incentive awards, executive benefits and severance payments under certain circumstances. 12. Commitments and contingencies, cont'd. Operating leases. The Company leases office space and office equipment under operating leases. Future minimum lease commitments at December 31, 2016 are as follows: Year ending December 31, Amount 2017 $ 15,895 2018 19,945 2019 22,420 2020 21,060 2021 19,099 2022 and thereafter 103,443 $ 201,862 Total lease expense under operating leases for the year ended December 31, 2016 was $12.8 million ( 2015 - $16.5 million ; 2014 - $14.7 million ). Total sublease income included in total lease expense under operating leases for the year ended December 31, 2016 was $0.4 million ( 2015 - $1.3 million ; 2014 - $1.3 million ). Legal Proceedings. The Company is party to various legal proceedings generally arising in the normal course of its business. While any proceeding contains an element of uncertainty, the Company does not believe that the eventual outcome of any litigation or arbitration proceeding to which it is presently a party could have a material adverse effect on its financial condition, results of operations or business. Pursuant to the Company's insurance and reinsurance agreements, disputes are generally required to be finally settled by arbitration.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Shareholders' Equity	13. Shareholders' equity The Company’s share capital at December 31, 2016 and 2015 is comprised as follows: 2016 2015 Preferred shares Authorized – $1.00 par value each 9,200 9,209,200 Issued, outstanding and fully paid: Series B preferred shares - $1.00 par value each; aggregate liquidation preference nil (2015 - $230,000) — 9,200,000 Series C preferred shares – $1.00 par value each; aggregate liquidation preference $230,000 (2015 - $230,000) 9,200 9,200 9,200 9,209,200 Common shares Authorized - $1.00 par value each 120,000,000 120,000,000 Issued, outstanding and fully paid: Ordinary common shares - $1.00 par value each 67,627,901 66,797,991 During 2016 , the Company issued restricted shares under its equity compensation plans (Note 16, Stock-based employee compensation and other stock plans). The common shares issued, outstanding and fully paid for at December 31, 2016 includes 1,396,538 restricted shares. On June 1, 2011, Endurance Holdings issued 9,200,000 shares of its 7.5% Non-Cumulative Preferred Shares, Series B (the "Series B Preferred Shares"). Endurance Holdings received net proceeds of $224.0 million from its offering of Series B Preferred Shares, after expenses and underwriting discounts. The proceeds from the Series B Preferred Shares were used to provide additional capital to Endurance Holdings' subsidiaries and for other general corporate purposes. 13. Shareholders' equity, cont'd. On November 24, 2015, Endurance Holdings issued 9,200 shares of its 6.35% Non-Cumulative Preferred Shares, Series C (the "Series C Preferred Shares") (equivalent to 9,200,000 Depositary Shares), each of which represents a 1/1,000th interest in a Series C Preferred Share, $1.00 par value and $25,000.00 liquidation preference per share (equivalent to $25.00 per Depositary Share). The Series C Preferred Shares sold were registered under the Securities Act of 1933, as amended. The Series C Preferred Shares were issued at a price to the public of $25,000.00 per share (equivalent to $25.00 per Depositary Share). Endurance Holdings received net proceeds of $222.0 million from its offering of Series C Preferred Shares, after expenses and underwriting discounts. The proceeds of the offering of Series C Preferred Shares were used to redeem on December 24, 2015 all 8,000,000 of Endurance Holdings' outstanding 7.75% Non-Cumulative Preferred Shares, Series A and for general corporate purposes. On June 1, 2016, Endurance Holdings redeemed all 9,200,000 of its Series B Preferred Shares. The Series B Preferred shares were redeemed at a redemption price of $25.00 per share together with an amount equal to any dividends that were declared but not paid prior to June 1, 2016. The Series C Preferred shares are traded on the New York Stock Exchange. The Series C Preferred Shares have no stated maturity date and are redeemable in whole or in part at the option of Endurance Holdings any time after December 15, 2020 at a redemption price of $25,000.00 per Series C Preferred Share (equivalent to $25.00 per Depositary Share), plus any declared and unpaid dividends, without accumulation of any undeclared dividends. Endurance Holdings may redeem all but not less than all of the Series C Preferred Shares before the redemption date at a redemption price of $26,000.00 per Series C Preferred Share (equivalent to $26.00 per Depositary Share), plus any declared and unpaid dividends to the date of redemption, if Endurance Holdings is required to submit a proposal to the holders of the Series C Preferred Shares concerning an amalgamation, consolidation, merger, similar corporate transaction, change in Bermuda law or other matter that requires the vote of the holders of the Series C Preferred Shares voting separately as a single class. Dividends on the Series C Preferred Shares, when, as and if declared by the Board of Directors of Endurance Holdings or a duly authorized committee of the board, accrue and are payable on the liquidation preference amount from the original issue date, quarterly in arrears on each dividend payment date, at an annual rate of 6.35%. Dividends on the Series C Preferred Shares are not cumulative. Upon any voluntary or involuntary liquidation, dissolution or winding-up of Endurance Holdings, holders of the Series C Preferred Shares and any parity shares are entitled to receive out of Endurance Holdings' assets available for distribution to shareholders, before any distribution is made to holders of Endurance Holdings' common equity securities, a liquidating distribution in the amount of $25,000.00 per Series C Preferred Share (equivalent to $25.00 per Depositary Share), plus any declared and unpaid dividends, without accumulation of any undeclared dividends. Distributions will be made pro rata as to the Series C Preferred Shares and any parity shares and only to the extent of Endurance Holdings' assets, if any, that are available after satisfaction of all liabilities to creditors. Holders of the Series C Preferred Shares have no voting rights, except with respect to certain dividend non-payments or as otherwise required by Bermuda law or Endurance Holdings' bye-laws. On February 25, 2016, the Company's Board of Directors authorized the repurchase of up to 5.0 million ordinary shares and share equivalents through February 28, 2018. This authorization superseded previous authorizations. No common shares were repurchased by the Company during 2016 or 2015 . Common shares repurchased by the Company are not canceled and are classified as treasury shares. The Company's treasury shares are recorded at cost as a reduction in common shares and additional paid-in capital within shareholders' equity. There were 5.0 million shares authorized for repurchase remaining at December 31, 2016 ( 2015 - 5.0 million ). 13. Shareholders' equity, cont'd. Accumulated other comprehensive loss The following table presents the changes in accumulated other comprehensive (loss) income balances by component for the years ended December 31, 2016 and 2015 : For the Year Ended December 31, 2016 Losses on cash flow hedges Unrealized (losses) gains on available for sale securities Foreign currency translation adjustments Total Beginning balance $ (1,678 ) $ (12,638 ) $ (32,318 ) $ (46,634 ) Other comprehensive (loss) income before reclassifications — 54,287 (86,324 ) (32,037 ) Amounts reclassified from accumulated other comprehensive loss (1) 88 19,834 — 19,922 Net current period other comprehensive loss 88 74,121 (86,324 ) (12,115 ) Ending balance $ (1,590 ) $ 61,483 $ (118,642 ) $ (58,749 ) (1) All amounts are net of tax. For the Year Ended December 31, 2015 Losses on cash flow hedges Unrealized (losses) gains on available for sale securities Foreign currency translation adjustments Total Beginning balance $ (1,766 ) $ 86,100 $ (7,628 ) $ 76,706 Other comprehensive (loss) income before reclassifications — (65,941 ) (24,690 ) (90,631 ) Amounts reclassified from accumulated other comprehensive loss (1) 88 (32,797 ) — (32,709 ) Net current period other comprehensive loss 88 (98,738 ) (24,690 ) (123,340 ) Ending balance $ (1,678 ) $ (12,638 ) $ (32,318 ) $ (46,634 ) (1) All amounts are net of tax. 13. Shareholders' equity, cont'd. The following tables present the significant items reclassified out of accumulated other comprehensive loss during the years ended December 31, 2016 and 2015 : For the Year Ended December 31, 2016 Details about accumulated other comprehensive loss components Amount reclassified from accumulated other comprehensive loss Affected line item in the Consolidated Statements of Income and Comprehensive Income Losses on cash flow hedges - Debt $ 88 Interest expense 88 Total before income taxes — Income tax expense $ 88 Total net of income taxes Unrealized holding losses (gains) on available for sale securities $ 7,984 Net realized and unrealized (losses) gains 10,769 Net impairment losses recognized in earnings 18,753 Total before income taxes 1,081 Income tax expense $ 19,834 Total net of income taxes For the Year Ended December 31, 2015 Details about accumulated other comprehensive loss components Amount reclassified from accumulated other comprehensive loss Affected line item in the Consolidated Statements of Income and Comprehensive Income Losses on cash flow hedges - Debt $ 88 Interest expense 88 Total before income taxes — Income tax expense $ 88 Total net of income taxes Unrealized holding losses (gains) on available for sale securities $ (37,245 ) Net realized and unrealized (losses) gains 3,715 Net impairment losses recognized in earnings (33,530 ) Total before income taxes 733 Income tax benefit $ (32,797 ) Total net of income taxes

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Share	14. Earnings per share The following table sets forth the computation of basic and diluted earnings per share for the years ended December 31, 2016 , 2015 and 2014 : 2016 2015 2014 Numerator: Net income available to common and participating common shareholders $ 333,218 $ 311,345 $ 315,700 Less amount allocated to participating common shareholders (1) (6,973 ) (8,749 ) (9,118 ) Net income allocated to common shareholders $ 326,245 $ 302,596 $ 306,582 Denominator: Weighted average shares - basic 65,991,947 52,707,390 43,368,062 Share equivalents: Options 65,351 118,392 47,111 Restricted shares and restricted share units 78,075 2,721 70 Weighted average shares - diluted 66,135,373 52,828,503 43,415,243 Basic earnings per common share $ 4.94 $ 5.74 $ 7.07 Diluted earnings per common share $ 4.93 $ 5.73 $ 7.06 (1) Represents earnings and dividends attributable to holders of unvested restricted shares and restricted share units issued under the Company's stock compensation plans that are considered participating. In periods of loss, no losses are allocated to participating common shareholders (unvested restricted shares and restricted share units). The following table sets forth dividends declared in the years ended December 31, 2016 , 2015 and 2014 , respectively: 2016 2015 2014 Dividends declared per Series A preferred share $ — $ 1.9375 $ 1.9375 Dividends declared per Series B preferred share $ 0.8646 $ 1.8750 $ 1.8750 Dividends declared per Series C preferred share $ 1,680.10 $ — $ — Dividends declared per common share $ 1.52 $ 1.40 $ 1.36 On June 1, 2016, Endurance Holdings redeemed all 9,200,000 of its Series B Preferred Shares. The Series B Preferred shares were redeemed at a redemption price of $25.00 per share together with an amount equal to any dividends that were declared but not paid prior to June 1, 2016.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	15. Related party transactions Fidelity Fidelity Institutional Asset Management, a subsidiary of FMR, LLC ("Fidelity"), provides investment management services to the Company. Fidelity and its affiliates previously owned greater than 5% of Endurance Holdings' ordinary shares outstanding and was considered a related party. At December 31, 2016 Fidelity and its affiliates were no longer considered a related party as Fidelity's share ownership was less than 5%. BlackRock Since 2002, subsidiaries of BlackRock Inc. ("BlackRock") have provided the Company and certain of its subsidiaries with various investment management, investment accounting and risk analysis services. BlackRock owned approximately 4.9 million or 7.3% of Endurance Holdings' ordinary shares outstanding at December 31, 2016 and were therefore considered a related party. The Company incurred expenses totaling $4.6 million ( 2015 : $3.6 million ; 2014 : $3.2 million ) for the year ended December 31, 2016 in relation to investment services rendered by BlackRock, of which $2.8 million was accrued at December 31, 2016 ( December 31, 2015 : $1.6 million ).

Stock-Based Employee Compensati

Stock-Based Employee Compensation And Other Stock Plans	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Employee Compensation And Other Stock Plans	16. Stock-based employee compensation and other stock plans At its meeting on February 28, 2007, the Company's Board of Directors adopted the 2007 Equity Incentive Plan ("2007 Plan") to allow for the issuance of equity incentives to non-employee directors of the Company and eligible employees of the Company and its subsidiaries. The 2007 Plan was approved by the Company's shareholders at the Annual General Meeting of Shareholders held on May 9, 2007. At that time, the Company's existing Amended and Restated 2002 Stock Option Plan and the Amended and Restated 2003 Non-Employee Director Incentive Plan were merged into the new 2007 Plan. The 2007 Plan allows the Company to grant to employees and non-employee directors restricted shares, restricted share units, stock appreciation rights, share bonuses, options to purchase the Company's ordinary shares and other forms of equity incentive awards, as determined by the Compensation Committee of the Company's Board of Directors. Under the terms of the 2007 Plan as amended, and after the consolidation of the Company's previous plans, a total of 2,100,000 ordinary shares were reserved for issuance. At a meeting on February 11, 2010, the Company's Board of Directors adopted a resolution to add 1,795,000 ordinary shares to the 2007 Plan, which was subsequently approved by the Company's shareholders at the Annual General Meeting of Shareholders held on May 13, 2010. Upon the acquisition of Montpelier, each Montpelier restricted share unit (including any restricted share units held by an executive officer or non-employee director) that was outstanding immediately prior to the completion of the acquisition of Montpelier subject solely to service-based vesting requirements (a "Montpelier Fixed RSU") was converted into a service-based restricted share unit under the 2007 Plan as amended, on the same terms and conditions as were applicable to such Montpelier Fixed RSU immediately prior to the completion of the acquisition of Montpelier. The number of service-based restricted share units granted was equal to the product of (i) 0.472, the exchange ratio in the Merger Agreement and (ii) the number of Montpelier common shares that were subject to such Montpelier Fixed RSU immediately prior to the completion of the acquisition. Upon completion of the acquisition of Montpelier, the number of Montpelier restricted share units that were outstanding immediately prior to the completion of the acquisition of Montpelier that were not Montpelier Fixed RSUs ("Montpelier Variable RSUs") was equal to the greater of: (i) the number of Montpelier Variable RSUs determined by using Montpelier’s actual performance as of the last completed quarter prior to the completion of the acquisition of Montpelier, as determined by the Compensation and Nominating Committee of the Montpelier board of directors prior to the completion of the acquisition of Montpelier after reasonable consultation with the Company, and (ii) the target number of Montpelier Variable RSUs. Each Montpelier Variable RSU that was outstanding immediately prior to the completion of the acquisition of Montpelier (including any Montpelier Variable RSUs that were held by an executive officer) was converted into a service-based restricted share unit under the 2007 Plan, as amended, on the same terms and conditions as were applicable to such Montpelier Variable RSU immediately prior to the completion of the acquisition of Montpelier. The number of service based restricted share units granted was equal to the product of (x) 0.472 , the exchange ratio in the Merger Agreement and (y) the number of Montpelier common shares that were subject to such Montpelier Variable RSU immediately prior to the completion of the acquisition. On August 3, 2015, the Company registered 842,755 ordinary shares for issuance. Upon completion of the acquisition of Montpelier, the Company assumed the Montpelier Re Holdings Ltd. 2012 Long-Term Incentive Plan (the "2012 Montpelier Equity Plan") and all awards outstanding thereunder and the future use of the remaining shares available for issuance under the 2012 Montpelier Equity Plan. The number of remaining shares under the 2012 Montpelier Equity Plan was adjusted pursuant to the terms of the Merger Agreement resulting in the registration of 1,025,349 ordinary shares under the 2007 Plan as amended, for future issuance thereunder. 16. Stock-based employee compensation and other stock plans, cont'd. After the approval of the additional shares, a total of 5,763,104 ordinary shares were reserved for issuance. The Company issues new ordinary shares upon the issuance of share based equity incentives, such as restricted shares, or the exercise or settlement of outstanding derivative equity incentives, such as options or restricted share units. As of December 31, 2016 , 2,071,035 ( 2015 - 2,463,798 ) ordinary shares remained available for issuance under the 2007 and prior Plans. On May 28, 2013, the Board of Directors elected John R. Charman as the Company's Chairman and Chief Executive Officer. Mr. Charman received an option to purchase 800,000 ordinary shares at an exercise price of $48.20 per share, and a grant of 708,890 restricted shares, as an employment inducement pursuant to Rule 303A.08 of the New York Stock Exchange Corporate Governance Standards and were made outside of the 2007 Plan. Options The 800,000 options awarded to Mr. Charman, as discussed above, vest annually, in five equal tranches commencing on May 28, 2013, subject to the Mr. Charman's continued employment, or in the event of certain terminations of employment and other events. Mr. Charman's options have a ten -year contractual life. The Company uses the Black-Scholes-Merton formula to estimate the value of stock options granted. Prior to 2005, the Company issued stock options to employees and non-employee directors, with exercise prices equal to the fair market values of the Company's ordinary shares on the grant dates. Options generally vested at a rate of 20% per year over a five -year term. Option awards had a 10 -year contractual life. Performance-Based Restricted Shares Commencing in March 2015, the Company issued performance-based restricted shares to certain of its senior executives under the 2007 Plan. The performance-based restricted shares represent the right to receive a specified number of ordinary shares in the future, based upon the achievement of pre-established performance criteria during the applicable performance period. Performance-based restricted shares granted to employees vest three years after the date of grant. The number of performance-based restricted shares that will ultimately vest is based upon the actual performance of the Company compared to the performance of a peer group of publicly-traded companies. Performance-based restricted shares are forfeited upon departure from the Company for any reason prior to the applicable vesting date other than in cases of death, disability, termination of employment in connection with a change in control or retirement. In the case of death, disability or change in control, 50% of the performance-based restricted shares will vest upon the date of death or disability or termination of employment in connection with a change in control. Where an employee meets certain retirement eligibility criteria, the performance-based restricted shares will continue to vest post-employment, subject to compliance with certain non-competition obligations. The fair value of the performance-based restricted shares is measured at the grant date using a Monte Carlo simulation based on pre-established targets relating to certain performance based measures achieved by the Company, with the associated expense recognized over the applicable performance and vesting period. Time-Based Restricted Shares The Company has issued time-based restricted shares to employees and non-employee directors of the Company's Board of Directors under the 2007 Plan. Restricted shares granted to employees generally vest pro-rata over a four -year period. Restricted shares are forfeited upon departure from the Company for any reason prior to the applicable vesting date other than in cases where an employee meets certain retirement eligibility criteria that allow for continuing post-employment vesting of restricted shares, subject to compliance with certain non-competition obligations. Restricted shares granted to non-employee directors vest twelve months following the date of grant and are forfeited upon departure of the non-employee director from the Company's Board of Directors for any reason prior to the applicable vesting date. 16. Stock-based employee compensation and other stock plans, cont'd. The 708,890 restricted shares awarded to Mr. Charman, as discussed above, vest annually, in five equal tranches commencing on May 28, 2013, subject to Mr. Charman’s continued employment, or in the event of certain terminations of employment and other events. Mr. Charman is party to a shareholders' agreement that restricts the sale of any vested restricted shares until 2018. The fair value of the restricted shares granted is equal to the fair market value of the Company's ordinary shares on the grant date. Compensation equal to the fair market value of the restricted shares at the measurement date is amortized and charged to income over the vesting period. Restricted Share Units The Company has issued restricted share units to employees in select jurisdictions where the issuance of restricted shares results in unfavorable tax treatment for employee recipients. Restricted shares granted to employees generally vest pro rata over a four -year period. Restricted share units are forfeited upon departure from the Company for any reason prior to the applicable vesting date other than in cases where an employee meets certain retirement eligibility criteria which allow for continuing post-employment vesting of restricted share units, subject to compliance with certain non-competition obligations. On July 31, 2015, upon completion of the Company's acquisition of Montpelier, outstanding Montpelier restricted share units were assumed by the Company and adjusted to represent the right to receive 0.472 of the Company's ordinary shares for each outstanding Montpelier restricted share unit rounded down to the next whole number of the Company's ordinary shares. The fair value of the restricted share units granted or assumed is equal to the fair market value of the Company's ordinary shares on the grant or assumption date, as applicable. Compensation equal to the fair market value of the restricted share units at the measurement date is amortized and charged to income over the vesting period. Summary of Stock-Based Employee Compensation Activity A summary of option activity, including options held by employees, during the year ended December 31, 2016 is presented below: For the year ended December 31, 2016 Options Outstanding Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (years) Aggregate Intrinsic Value Beginning of year 320,000 $ 48.20 Granted — — Exercised (160,000 ) 48.20 Forfeited — — Outstanding, end of year 160,000 $ 48.20 6.41 $ 7,072 Exercisable and vested options, end of year — $ — N/A $ — No options were granted or expired during the years ended December 31, 2016 , 2015 , and 2014 . During the years ended December 31, 2016 , 2015 and 2014 , 160,000 , 160,000 and 160,000 options vested, respectively. The total intrinsic value of options exercised during the years ended December 31, 2016 , 2015 and 2014 was $3.2 million , $9.5 million , and $0.3 million , respectively. The Company received proceeds of $7.7 million from the exercise of options during the year ended December 31, 2016 . The Company issued new ordinary shares in connection with the exercise of the above options. For the years ended December 31, 2016 , 2015 and 2014 , compensation costs recognized in earnings for all options totaled $0.8 million , $1.6 million and $3.1 million , respectively. There were unrecognized stock-based compensation expenses of $0.2 million related to unvested stock options at December 31, 2016 ( 2015 - $1.0 million ). This expense is expected to be recognized in 2017 . 16. Stock-based employee compensation and other stock plans, cont'd. A summary of the restricted share and restricted share unit activity during the year ended December 31, 2016 , is presented below: Number of Shares/Units Aggregate Intrinsic Value Unvested, beginning of year 1,663,582 Granted 638,217 Settled (769,445 ) Forfeited (65,638 ) Unvested, end of year 1,466,716 Outstanding, end of year 1,466,716 $ 135,525 During the years ended December 31, 2016 , 2015 and 2014 , the Company granted an aggregate of 638,217 , 1,388,179 and 505,997 restricted shares and restricted share units under the 2007 Plan. As mentioned above, during the year ended December 31, 2015, the Company also assumed 841,926 , the converted outstanding Montpelier restricted share units, adjusted to represent the right to receive 0.472 of the Company's ordinary shares for each outstanding Montpelier restricted share unit rounded down to the next whole number of ordinary shares. The restricted shares and restricted share units granted had weighted average grant date fair values of $38.5 million , $91.2 million and $26.7 million in the years ended December 31, 2016 , 2015 and 2014 , respectively. During the years ended December 31, 2016 , 2015 and 2014 , the aggregate fair value of restricted shares and restricted share units that vested was $44.3 million , $60.0 million and $18.7 million , respectively. For the years ended December 31, 2016 , 2015 and 2014 , compensation costs recognized in earnings for all restricted shares and restricted share units were $35.7 million , $53.9 million , and $27.9 million , respectively. At December 31, 2016 , compensation costs not yet recognized related to non-vested awards was $26.2 million ( 2015 - $26.7 million ). This expense is expected to be recognized between 2017 and 2020, with approximately 65.3% expected to be recognized during 2017 . Employee Share Purchase Plan On October 26, 2005, Endurance Holdings' shareholders approved the Employee Share Purchase Plan (the "2005 ESPP"). Following approval by the Company's shareholders in 2005, 200,000 of Endurance Holdings' ordinary shares were reserved for issuance under the 2005 ESPP. At a meeting on February 23, 2011, the Company's Board of Directors adopted a resolution to add 200,000 ordinary shares to the 2005 ESPP. The addition of 200,000 ordinary shares to the 2005 ESPP was approved by the Company's shareholders at the Annual General Meeting of Shareholders held on May 11, 2011. After approval of the additional ordinary shares, a total of 400,000 ordinary shares were reserved for issuance under the 2005 ESPP. The 2005 ESPP terminated in accordance with its terms on October 1, 2015. On February 26, 2015, the Compensation Committee of the Company's Board of Directors approved a new employee share purchase plan ("2015 ESPP"), which was approved by the Company's shareholders at its Annual General Meeting of Shareholders held on May 20, 2015. The Company ceased offering and issuing new shares under the 2005 ESPP on June 30, 2015 and began offering and issuing new shares under the 2015 ESPP after July 1, 2015. Following approval by the Company's shareholders in 2015, 300,000 of Endurance Holdings' ordinary shares were reserved for issuance under the 2015 ESPP. The 2015 ESPP is not subject to any provisions of the Employee Retirement Income Security Act of 1974 as amended, and is not a qualified plan within the meaning of Section 402(a) of the Internal Revenue Code of 1986, as amended (the "Code"). The ESPP is a qualified plan under Section 423 of the Code. Under the terms of the 2015 ESPP, employees of Endurance Holdings and certain of its subsidiaries may purchase Endurance Holdings' ordinary shares at a 15% discount to the closing market price on the purchase date. Participants are eligible to receive dividends on the shares purchased in the 2015 ESPP and are entitled to vote such shares at any Annual General or Special Meeting of Shareholders. These shares are restricted from sale, transfer or certification for one year from the purchase date. On signing of the Merger Agreement with Sompo, the 2015 ESPP was suspended as of January 1, 2017 and will be terminated if and when the Merger closes. Total expenses related to this plan for the year ended December 31, 2016 was approximately $425,000 ( 2015 - $298,000 ; 2014 - $234,000 ).

Pension Plan

Pension Plan	12 Months Ended
	Dec. 31, 2016
Pension and Other Postretirement Benefit Expense [Abstract]
Pension Plan	17. Pension plan The Company provides pension benefits to eligible employees through various defined contribution plans sponsored by the Company. Under the Company's defined contribution plans, the Company makes contributions to its employees' accounts in amounts ranging from 4% to 12% of its employees’ eligible earnings. In addition, under certain defined contribution plans, employee contributions may be supplemented by matching contributions made by the Company based on the level of employee contribution. Lastly, the Company may provide additional contributions, depending on its annual financial performance. The employee and Company contributions in the defined contribution plans are invested at the election of each employee in one or more of several investment portfolios offered by third party investment advisors. Company contributions for the year ended December 31, 2016 resulted in an expense of $15.8 million being recorded in earnings ( 2015 - $13.8 million ; 2014 - $12.6 million ).

Statutory Requirements And Divi

Statutory Requirements And Dividend Restrictions	12 Months Ended
	Dec. 31, 2016
Statutory Requirements And Dividend Restrictions [Abstract]
Statutory Requirements And Dividend Restrictions	18. Statutory requirements and dividend restrictions The Company's insurance and reinsurance operations are subject to insurance and/or reinsurance laws and regulations in the jurisdictions in which they operate, the most significant of which are Bermuda, the United States, the United Kingdom and Singapore. These regulations include certain restrictions on the amount of dividends or other distributions, such as loans or cash advances, available to shareholders without prior approval of the insurance regulatory authorities. The combined statutory capital and combined statutory net income (loss) for the Company's principal operating subsidiaries, excluding Syndicate 5151, in their respective jurisdictions were as follows: Statutory capital Bermuda United States U.K. (1) Singapore 2016 2015 2016 2015 2016 2015 2016 2015 Required statutory capital $ 1,614,465 $ 1,276,453 $ 350,947 $ 281,905 $ 184,799 $ 84,086 $ 3,461 $ 3,524 Actual statutory capital 4,525,290 4,307,249 810,704 768,791 451,257 538,265 59,025 49,842 Statutory net income (loss) Bermuda United States U.K. Singapore Year ended December 31, 2016 $ 486,254 $ 64,688 $ 79,912 $ 10,460 Year ended December 31, 2015 417,298 70,398 969 17,542 Year ended December 31, 2014 453,127 28,450 4,135 4,111 (1) U.K. includes the statutory capital of Endurance U.K. Bermuda As a Bermuda holding company, Endurance Holdings is subject to the Bermuda Companies Act 1981, which limits the Company's ability to pay dividends and make distributions to its shareholders. The Company's retained earnings are unrestricted; however, the Company is not permitted to declare or pay a dividend, or make a distribution out of contributed surplus, if it is, or would after the payment be, unable to pay its liabilities as they come due, or if the realizable value of its assets would be less than its liabilities. Endurance Holdings had, as of December 31, 2016 , $2.9 billion in retained earnings and an additional $2.0 billion in contributed surplus available to declare or pay a dividend, or make a distribution out of contributed surplus, so long as Endurance Holdings remained in compliance with the Bermuda Companies Act 1981 following such dividend or distribution. Endurance Holdings relies on dividends from Endurance Bermuda to provide cash flow required for debt service and dividends to shareholders. 18. Statutory requirements and dividend restrictions, cont'd. Endurance Bermuda Endurance Bermuda is a registered Class 4 insurer under the Insurance Act 1978 ("Bermuda Insurance Act") and related regulations as amended (the "Insurance Act"). Endurance Bermuda is required to maintain minimum solvency standards and to hold available statutory capital and surplus equal to or exceeding the Enhanced Capital Requirement as determined by the Bermuda Monetary Authority ("BMA") based upon a standard mathematical model that correlates the risk underwritten to the capital that is dedicated to the business. The required capital noted in the table above has been based on the Enhanced Capital Requirement. In addition to the Enhanced Capital Requirement, Endurance Bermuda is required to maintain a minimum statutory liquidity ratio and solvency margin. For all periods presented herein, Endurance Bermuda materially exceeded these minimum requirements. Endurance Bermuda's ability to pay dividends and make capital distributions is subject to certain regulatory restrictions based on the Enhanced Capital Requirement, limits on the amount of Endurance Bermuda's premiums written and net reserves for losses and loss expenses and a minimum general capital and surplus requirement of $100.0 million . At December 31, 2016 , Endurance Bermuda can pay dividends of $1,109.3 million ( 2015 - $1,034.4 million ) to Endurance Holdings without prior approval under Bermuda law. Blue Water Re and Blue Water Re II Blue Water Re and Blue Water Re II are registered with the BMA as Special Purpose Insurers and are not subject to the BMA's Bermuda Solvency Capital Requirement ("BSCR"); however, the Bermuda Insurance Act limits the maximum amount of annual dividends and distributions that may be paid by Blue Water Re and Blue Water Re II. There is no minimum solvency margin or liquidity ratio that must be maintained by Blue Water Re or Blue Water Re II so long as the value of their assets exceed the value of their liabilities. At December 31, 2016 , Blue Water Re's assets exceeded the value of its liabilities by $263.1 million ( 2015 - $269.6 million ), and Blue Water Re II's assets exceeded the value of its liabilities by $11.3 million ( 2015 - $212.5 million ). Blue Water Re and Blue Water Re II did not declare or pay any dividends to their parent, BCML, during 2016 . Blue Capital Re Blue Capital Re is registered with the BMA as a Class 3A insurer. The Bermuda Insurance Act requires Blue Capital Re to maintain minimum levels of statutory capital and surplus to maintain minimum liquidity ratios and to meet minimum solvency margins. At December 31, 2016 , Blue Capital Re exceeded these minimum requirements. At December 31, 2016 , Blue Capital Re can pay dividends of $45.9 million ( 2015 - $50.6 million ) to it's parent without prior approval under Bermuda law. BCML BCML is licensed and supervised by the BMA to carry on investment business and as an insurance agent/manager. BCML is not subject to any material minimum solvency requirements. United States Endurance Assurance, Endurance American, Endurance American Specialty and Endurance Risk Solutions are subject to regulation by the Delaware Department of Insurance. American Agri-Business is subject to regulation by the Texas Department of Insurance. Endurance Holdings' Delaware and Texas domiciled entities must maintain a minimum level of statutory capital as established by such jurisdictions. The amount of required capital is determined through the use of the Risk Based Capital model established by the National Association of Insurance Commissioners and adopted by Delaware and Texas. The required capital noted in the table above has been based on the Risk Based Capital model and represents the authorized control level risk based capital for these entities. Dividends for each U.S. operating subsidiary are limited to the greater of 10% of policyholders' surplus or statutory net income, excluding realized capital gains for Endurance Holdings' Delaware domiciled entities. In addition, dividends may only be declared or distributed out of earned surplus. At December 31, 2016 , Endurance Assurance, Endurance American, Endurance Risk Solutions and Endurance American Specialty did not have earned surplus and thus were precluded from declaring or distributing dividends during 2016 without the prior approval of the applicable insurance regulator. If the parent company is also an insurer, as is the case with Endurance American, Endurance American Specialty and Endurance Risk Solutions, the parent company or companies must also meet their own dividend eligibility requirements in order to pass along any dividends received from subsidiary insurance companies. At December 31, 2016 , American Agri-Business (with notice to the Texas Department of Insurance) could pay dividends of $3.3 million ( 2015 - $3.5 million ) without prior regulatory approval. 18. Statutory requirements and dividend restrictions, cont'd. U.K. Endurance U.K. The required and actual statutory capital amounts in the "U.K." category in the table above include amounts related to Endurance U.K. Under the jurisdiction of the United Kingdom's Prudential Regulation Authority ("PRA"), Endurance U.K. must maintain a margin of solvency at all times under the Solvency II Directive from the European Insurance and Occupational Pensions Authority which was effective January 1, 2016. The regulations stipulate that insurers are required to calculate their minimum capital requirement and solvency capital requirement ("SCR"). Insurers can either apply for approval of an internal model to calculate the SCR or adopt the standard formula. Endurance U.K. has utilized the standard formula for the SCR as of December 31, 2016. As of December 31, 2015, the SCR was based upon Solvency I to calculate the capital requirement under Individual Capital Guidance, the risk based capital assessment, superseded by Solvency II. At December 31, 2016 and 2015 , the actual capital for Endurance U.K. exceeded all of the capital requirements promulgated by the PRA. The PRA regulatory requirements impose no explicit restrictions on Endurance U.K.'s ability to pay a dividend, but Endurance U.K. would have to notify the PRA 28 days prior to any proposed dividend payment. Dividends may only be distributed from profits available for distribution. At December 31, 2016 Endurance U.K did not have retained profits available for distribution. Endurance at Lloyd's The Company participates in the Lloyd's market through Syndicate 5151, which is managed by Endurance at Lloyd's and is capitalized through ECCL. As a corporate member of Lloyd's, ECCL is subject to the oversight of the Council of Lloyd's. ECCL is required to deposit cash, securities or letters of credit (or a combination of these assets) with Lloyd's in order to satisfy its FAL requirements, which are met through the Lloyd's Capital Trust. At December 31, 2016 , ECCL had total FAL of $323.6 million ( 2015 - $276.8 million ) which was provided by Endurance Bermuda. Singapore Endurance Bermuda's Singapore branch ("Singapore Branch") is subject to Fund Solvency and Capital Adequacy requirements by the Monetary Authority of Singapore as a foreign company in Singapore and is regulated by the Monetary Authority of Singapore pursuant to the Insurance Act in Singapore. At December 31, 2016 and 2015 , the Singapore Branch complied with the capital requirements promulgated by the Monetary Authority of Singapore. Switzerland In 2008, Endurance Bermuda established a branch in Zurich, Switzerland named Endurance Specialty Insurance Ltd. Pembroke (Bermuda) Zurich Branch. In 2015, Endurance U.K. established a branch in Zurich named Endurance Worldwide Insurance Limited, London, Zurich Branch. Swiss law does not impose additional regulation upon a Swiss branch of a foreign reinsurer.

Taxes

Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Taxes	19. Taxes The Company has operating subsidiaries and branch operations in the United States, United Kingdom, Switzerland and Singapore, which are subject to the relevant taxes in those jurisdictions. During 2014, the United States Internal Revenue Service ("IRS") completed its audit of the income tax returns of of the Company's U.S. subsidiaries for 2009, 2010 and 2011. The audit results were immaterial to the operations of the Company. During 2015, the IRS commenced an examination of the 2012 income tax return of Endurance Bermuda. Although the timing and ultimate resolution of the IRS examinations is uncertain, the Company does not expect the resolution of the examinations to result in a material change to the Company's financial position, results of operations or cash flows. In January 2017, the Switzerland tax authority issued a tax assessment for the Swiss branch of Endurance Bermuda for years 2013 and 2014. The Company disagrees with the assessment and is appealing the assessment. Although the timing and ultimate resolution of the Swiss assessment is uncertain, the Company does not expect the resolution of the examinations to result in a material change to the Company's financial position, results of operations or cash flows. As of December 31, 2016 , none of the Company's other operating subsidiaries or branch operations were under examination in any of the jurisdictions in which they operate. The Company remains subject to examination for tax years 2008 through 2016. 19. Taxes, cont'd. Endurance Holdings and Endurance Bermuda are not required to pay any income or capital gains taxes in Bermuda. Endurance Bermuda has received written assurance dated May 16, 2011 and Endurance Holdings has received written assurance dated May 17, 2011 from the Minister of Finance of Bermuda under the Exempted Undertakings Tax Protection Act of 1966 of Bermuda, as amended, that in the event any legislation is enacted in Bermuda imposing any tax computed on profits or income, or computed on any capital asset, gain or appreciation or any tax in the nature of estate duty or inheritance tax, such tax shall not be applicable to the Company until March 31, 2035 provided that the assurance is subject to the condition that it will not prevent the application of any taxes payable by the Company in respect of real property or leasehold interests in Bermuda held by it. Endurance Holdings and Endurance Bermuda intend to operate in a manner such that they will owe no United States tax other than premium excise tax and withholding taxes on certain investments. The income tax benefit (expense) was as follows for the years ended December 31, 2016 , 2015 and 2014 , respectively: 2016 2015 2014 Current income tax expense $ (10,993 ) $ (6,262 ) $ (1,804 ) Deferred income tax benefit 11,174 1,900 1,414 Income tax benefit (expense) $ 181 $ (4,362 ) $ (390 ) Of the 2016 current income tax expense, $ 1.8 million related to taxes incurred in the United States ( 2015 - $ 4.2 million ; 2014 - $1.8 million ), $4.2 million related to taxes incurred in the United Kingdom ( 2015 - $2.2 million ; 2014 - nil ) and $5.0 million related to taxes incurred in Switzerland ( 2015 - $0.1 million tax benefit; 2014 - nil ). Of the deferred income tax benefit, $5.2 million related to deferred income tax benefit in the United States ( 2015 - $0.7 million ; 2014 - $1.4 million ), $1.7 million related to deferred income tax benefit in the United Kingdom ( 2015 - $0.2 million ; 2014 - nil ) and $4.2 million related to deferred income tax benefit in Bermuda including its branches ( 2015 - $1.0 million ; 2014 - nil ). The deferred income tax benefit in Bermuda related to amortization of intangible assets from the acquisition of Montpelier which the Company elected not to push down to Endurance at Lloyd's under current accounting guidance. In 2016 a full valuation allowance has been recorded against the net deferred asset position of Endurance Bermuda's branches in Singapore and Switzerland. In 2015 a full valuation allowance had been recorded against the net asset position of Endurance Bermuda's branches in Singapore and Switzerland and a United Kingdom subsidiary. The actual income tax benefit (expense) attributable to income for the years ended December 31, 2016 , 2015 and 2014 differed from the amount computed by applying the combined effective rate of 0% under Bermuda law to income before income taxes, as a result of the following: 2016 2015 2014 Computed expected tax expense $ — $ — $ — Tax expense effect on foreign taxes (26,149 ) (8,071 ) (1,661 ) Change in valuation allowance 26,330 3,709 1,271 Income tax benefit (expense) $ 181 $ (4,362 ) $ (390 ) 19. Taxes, cont'd. Deferred income taxes represent the tax effect of the differences between the book and tax bases of assets and liabilities. Net deferred income tax assets and liabilities consisted of the following as of December 31, 2016 and 2015 : 2016 2015 Deferred income tax assets: Unearned premiums $ 28,523 $ 25,172 Loss reserves 26,594 27,370 Net operating loss carryforward 66,315 92,844 Deferred compensation 26,451 25,268 Deferred interest 48,359 46,568 Unrealized investment losses 1,803 1,568 Realized investment losses 4,010 4,972 Other 3,830 11,077 Total deferred income tax assets 205,885 234,839 Deferred income tax liabilities: Deferred acquisition costs (1,325 ) (8,179 ) Unrealized foreign exchange gains — (4,087 ) Temporary differences related to acquisition (29,033 ) (35,461 ) Start up costs (1,989 ) (1,565 ) Other (10,002 ) (7,561 ) Total deferred income tax liabilities (42,349 ) (56,853 ) Valuation allowance (104,808 ) (131,138 ) Net deferred income tax asset $ 58,728 $ 46,848 Net income tax payments for the years ended December 31, 2016 , 2015 and 2014 totaled $7.8 million , $2.4 million , and $0.9 million respectively. Net operating loss carryforwards gross of tax in the amount of $119.8 million , $45.9 million , $61.1 million and $44.5 million are available for application against future taxable income in the United States, United Kingdom, and Endurance Bermuda's branches in Singapore and Switzerland, respectively. These net operating loss carry forwards have no expiration date in the United Kingdom and Singapore. In Switzerland and the United States, the net operating loss carry forwards expire through 2016 and 2028, respectively. A valuation allowance is provided when it is more likely than not that some portion of the deferred tax assets will not be realized. At December 31, 2016 , management has established a valuation allowance of $104.8 million ( 2015 - $131.1 million ) against net deferred tax assets in the Company's United States subsidiaries and Endurance Bermuda's Singapore and Switzerland branches. The Company's income before income taxes was distributed as follows for the years ended December 31, 2016 , 2015 and 2014 , respectively: 2016 2015 2014 U.S. (domestic) $ 40,872 $ 95,649 $ 60,112 Non-U.S. (foreign) (1) 340,094 263,824 288,728 Income before income taxes $ 380,966 $ 359,473 $ 348,840 (1) The Company's non-U.S. (foreign) operating subsidiaries write business that is exposed to risks originating in the United States. In 2015 Management concluded that valuation allowances were required against the net operating loss and net capital loss carryforwards assumed as part of the Montpelier acquisition. The valuation allowances had been established as Internal Revenue Code Section 382 limits the application of net operating loss and net capital loss carryforwards following an ownership change. Accordingly, a tax effected valuation allowance of $11.6 million and $0.7 million , respectively, was required as of August 1, 2015 . The Montpelier capital loss carryforwards have fully expired. The operating loss carryforwards available per year are $0.2 million as required by Internal Revenue Code Section 382. 19. Taxes, cont'd. As of December 31, 2016 and 2015 , the Company had no material uncertain tax positions.

Condensed Unaudited Quarterly F

Condensed Unaudited Quarterly Financial Data	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Condensed Unaudited Quarterly Financial Data	20. Condensed unaudited quarterly financial data The following is a summary of the unaudited quarterly data for the year ended December 31, 2016 : Quarter Ended Quarter Ended Quarter Ended Quarter Ended Net premiums earned $ 553,191 $ 599,608 $ 610,156 $ 600,705 Net investment income 11,181 43,977 62,236 59,196 Net realized and unrealized gains (losses) 13,787 6,347 13,405 (45,958 ) Net impairment losses recognized in earnings (623 ) (9,841 ) (183 ) (122 ) Subtotal $ 577,536 $ 640,091 $ 685,614 $ 613,821 Net losses and loss expenses $ 243,328 $ 376,112 $ 331,462 $ 370,150 Acquisition, general and administrative, and corporate expenses $ 187,838 $ 178,870 $ 201,081 $ 192,546 Net foreign exchange gains $ (11,729 ) $ (32,751 ) $ (18,576 ) $ (11,628 ) Net income $ 124,644 $ 87,628 $ 139,400 $ 29,475 Net income attributable to non-controlling interests (9,063 ) (3,714 ) (5,679 ) (5,674 ) Net income available to Endurance Holdings $ 115,581 $ 83,914 $ 133,721 $ 23,801 Preferred dividends (9,203 ) (7,293 ) (3,651 ) (3,652 ) Net income available to Endurance Holdings' common and participating common shareholders $ 106,378 $ 76,621 $ 130,070 $ 20,149 Basic earnings per share $ 1.58 $ 1.14 $ 1.93 $ 0.30 Diluted earnings per share $ 1.58 $ 1.14 $ 1.92 $ 0.30 The following is a summary of the unaudited quarterly data for the year ended December 31, 2015 : Quarter Ended Quarter Ended Quarter Ended Quarter Ended Net premiums earned $ 389,859 $ 458,135 $ 557,003 $ 573,456 Net investment income 41,861 32,252 16,533 23,180 Net realized and unrealized gains (losses) 18,189 9,680 5,029 (20,238 ) Net impairment losses recognized in earnings (649 ) (424 ) (38 ) (2,604 ) Subtotal $ 449,260 $ 499,643 $ 578,527 $ 573,794 Net losses and loss expenses $ 171,936 $ 239,122 $ 263,993 $ 242,057 Acquisition, general and administrative, and corporate expenses $ 149,251 $ 152,570 $ 225,558 $ 194,726 Net foreign exchange losses (gains) $ 7,552 $ 12,981 $ 8,621 $ (2,190 ) Net income $ 108,479 $ 84,206 $ 54,530 $ 107,896 Net income attributable to non-controlling interests — — (2,707 ) (8,309 ) Net income available to Endurance Holdings $ 108,479 $ 84,206 $ 51,823 $ 99,587 Preferred dividends (8,188 ) (8,188 ) (8,188 ) (8,186 ) Net income available to Endurance Holdings' common and participating common shareholders $ 100,291 $ 76,018 $ 43,635 $ 91,401 Basic earnings per share $ 2.24 $ 1.69 $ 0.73 $ 1.36 Diluted earnings per share $ 2.23 $ 1.68 $ 0.73 $ 1.36

Schedule I Summary Of Investmen

Schedule I Summary Of Investments Other Than Investments In Related Parties	12 Months Ended
	Dec. 31, 2016
Summary of Investments, Other than Investments in Related Parties [Abstract]
Schedule I Summary Of Investments Other Than Investments In Related Parties	SCHEDULE I ENDURANCE SPECIALTY HOLDINGS LTD. AND SUBSIDIARIES SUMMARY OF INVESTMENTS OTHER THAN INVESTMENTS IN RELATED PARTIES AT DECEMBER 31, 2016 (In thousands of United States dollars) Cost (1) Market Value Amount at Which Shown on the Balance Sheet Type of Investment: Fixed Maturity Investments U.S. government and government agencies and authorities $ 1,003,969 $ 1,001,882 $ 1,001,882 States, municipalities and political subdivisions 17,115 18,357 18,357 Foreign governments 180,583 178,919 178,919 Corporate bonds 2,120,463 2,151,610 2,151,610 Mortgage-backed securities Agency mortgage-backed securities 1,461,354 1,472,343 1,472,343 Non-agency mortgage-backed securities 603,293 607,791 607,791 Collateralized loan and debt obligations 369,126 371,256 371,256 Asset-backed securities 509,595 510,663 510,663 Total fixed maturity investments $ 6,265,498 $ 6,312,821 $ 6,312,821 Short-term investments 408,811 408,704 408,704 Equity securities 477,778 501,141 501,141 Other investments 470,299 588,308 588,308 Total Investments $ 7,622,386 $ 7,810,974 $ 7,810,974 (1) Investments in fixed maturity investments and short-term investments are shown at amortized cost.

Schedule II Condensed Financial

Schedule II Condensed Financial Statement Information Of The Registrant	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Schedule II Condensed Financial Statement Information of the Registrant	SCHEDULE II ENDURANCE SPECIALTY HOLDINGS LTD. CONDENSED FINANCIAL STATEMENT INFORMATION OF THE REGISTRANT BALANCE SHEETS-PARENT ONLY DECEMBER 31, 2016 AND 2015 (In thousands of United States dollars except share amounts) 2016 2015 ASSETS Investment in subsidiary $ 5,296,821 $ 5,683,801 Cash and cash equivalents 3,375 3,206 Amounts due from subsidiaries 513,621 105,497 Goodwill and intangible assets 45,710 51,938 Other assets 12,833 14,435 Total assets $ 5,872,360 $ 5,858,877 LIABILITIES Debt $ 708,378 $ 707,591 Other liabilities 21,849 27,214 Total liabilities 730,227 734,805 SHAREHOLDERS' EQUITY Preferred shares Series B and C, non-cumulative - 9,200 issued and outstanding (2015 - 9,209,200) 9 9,209 Common shares Common shares, ordinary - 67,627,901 issued and outstanding (2015 - 66,797,991) 67,628 66,798 Additional paid-in capital 1,961,917 2,145,836 Accumulated other comprehensive loss (58,749 ) (46,634 ) Retained earnings 2,911,634 2,681,053 Total shareholders' equity available to Endurance Holdings 4,882,439 4,856,262 Non-controlling interests 259,694 267,810 Total shareholders' equity 5,142,133 5,124,072 Total liabilities and shareholders' equity $ 5,872,360 $ 5,858,877 See accompanying notes to the consolidated financial statements. SCHEDULE II ENDURANCE SPECIALTY HOLDINGS LTD. CONDENSED FINANCIAL STATEMENT INFORMATION OF THE REGISTRANT, Cont’d. STATEMENTS OF INCOME-PARENT ONLY YEARS ENDED DECEMBER 31, 2016 , 2015 , AND 2014 (In thousands of United States dollars) 2016 2015 2014 Revenues Net investment income $ 5 $ 9 $ 248 Net realized and unrealized gains 206 332 1,957 Other income 10,200 10,200 10,200 Total revenues 10,411 10,541 12,405 Expenses General and administrative expenses 41,879 93,237 61,325 Amortization of intangibles 6,228 1,558 — Net foreign exchange (gains) losses (20 ) 5 (1 ) Interest expense 43,833 41,188 40,968 Total expenses 91,920 135,988 102,292 Loss before income taxes and equity in net income of subsidiaries (81,509 ) (125,447 ) (89,887 ) Equity in net income of subsidiaries 462,656 480,558 438,337 Net income 381,147 355,111 348,450 Net income attributable to non-controlling interests (24,130 ) (11,016 ) — Net income available to Endurance Holdings 357,017 344,095 348,450 Preferred dividends (23,799 ) (32,750 ) (32,750 ) Net income available to Endurance Holdings' common and participating common shareholders $ 333,218 $ 311,345 $ 315,700 See accompanying notes to the consolidated financial statements SCHEDULE II ENDURANCE SPECIALTY HOLDINGS LTD. CONDENSED FINANCIAL STATEMENT INFORMATION OF THE REGISTRANT, Cont’d. STATEMENTS OF CASH FLOWS-PARENT ONLY YEARS ENDED DECEMBER 31, 2016 , 2015 , AND 2014 (In thousands of United States dollars) 2016 2015 2014 Cash flows used in operating activities: Net income $ 381,147 $ 355,111 $ 348,450 Adjustments to reconcile net income to net cash used in operating activities: Depreciation and amortization 8,380 3,738 6,785 Net realized and unrealized gains (206 ) (332 ) (1,957 ) Stock-based compensation expense 9,339 28,604 15,093 Equity in net earnings of subsidiary (462,656 ) (480,558 ) (438,337 ) Other assets 327 (893 ) (177 ) Other liabilities (3,524 ) (17,377 ) 1,626 Net cash flows used in operating activities (67,193 ) (111,707 ) (68,517 ) Cash flows provided by investing activities: Proceeds from sales and maturities of available for sale investments — — 26,094 Purchases of available for sale investments — — (24,137 ) Contributions of capital made to subsidiaries (4,655 ) — — Dividends received from subsidiary 809,840 341,524 145,203 Net amounts paid to subsidiaries (379,632 ) 35,383 14,819 Purchases of fixed assets — (11,626 ) — Proceeds from disposals of fixed assets — 6,606 19 Net cash received for subsidiary acquisition — 19,875 — Net cash flows provided by investing activities 425,553 391,762 161,998 Cash flows used in financing activities: Issuance of common shares 10,076 24,823 2,305 Issuance of Series C, non-cumulative preferred shares — 222,963 — Redemption of Series A and B, non-cumulative preferred shares (230,000 ) (200,000 ) — Offering and registration costs paid (319 ) (617 ) — Bridge facility costs paid — — (4,750 ) Settlement of restricted shares (11,732 ) (14,535 ) (4,039 ) Repayments of debt — (198,500 ) — Dividends paid on preferred shares (23,799 ) (32,750 ) (32,750 ) Dividends paid on common shares (102,417 ) (78,473 ) (60,524 ) Net cash flows used in financing activities (358,191 ) (277,089 ) (99,758 ) Net increase (decrease) in cash and cash equivalents 169 2,966 (6,277 ) Cash and cash equivalents, beginning of year 3,206 240 6,517 Cash and cash equivalents, end of year $ 3,375 $ 3,206 $ 240 See accompanying notes to the consolidated financial statements

Schedule III Supplementary Insu

Schedule III Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2016
Supplementary Insurance Information [Abstract]
Schedule III Supplementary Insurance Information	SCHEDULE III ENDURANCE SPECIALTY HOLDINGS LTD. AND SUBSIDIARIES SUPPLEMENTARY INSURANCE INFORMATION YEARS ENDED DECEMBER 31, 2016 , 2015 , AND 2014 (In thousands of United States dollars) Year Ended December 31, 2016 Insurance Reinsurance Total Deferred Acquisition Costs $ 72,502 $ 204,137 $ 276,639 Reserve for Losses and Loss Expenses 2,798,989 2,106,149 4,905,138 Unearned Premiums 1,124,359 870,317 1,994,676 Net Premiums Earned 1,009,375 1,354,285 2,363,660 Net Investment Income (1) — — 176,590 Net Losses and Loss Expenses 684,178 636,874 1,321,052 Amortization of Deferred Acquisition Costs 149,763 310,720 460,483 Other Operating Expenses (2) 140,742 107,404 248,146 Net Premiums Written 1,056,254 1,313,681 2,369,935 (1) Because the Company does not manage its assets by segment, investment income is not allocated to the individual segments. (2) General and administrative expenses incurred by segments are allocated directly. Remaining general and administrative expenses not incurred by the segments are classified as corporate expenses and are not allocated to the individual business segments. Year Ended December 31, 2015 Insurance Reinsurance Total Deferred Acquisition Costs $ 58,216 $ 197,285 $ 255,501 Reserve for Losses and Loss Expenses 2,493,894 2,016,521 4,510,415 Unearned Premiums 902,152 886,996 1,789,148 Net Premiums Earned 824,552 1,153,901 1,978,453 Net Investment Income (1) — — 113,826 Net Losses and Loss Expenses 500,867 416,241 917,108 Amortization of Deferred Acquisition Costs 80,252 267,633 347,885 Other Operating Expenses (2) 140,012 119,779 259,791 Net Premiums Written 880,373 1,070,097 1,950,470 (1) Because the Company does not manage its assets by segment, investment income is not allocated to the individual segments. (2) General and administrative expenses incurred by segments are allocated directly. Remaining general and administrative expenses not incurred by the segments are classified as corporate expenses and are not allocated to the individual business segments. SCHEDULE III ENDURANCE SPECIALTY HOLDINGS LTD. AND SUBSIDIARIES SUPPLEMENTARY INSURANCE INFORMATION, Cont’d YEARS ENDED DECEMBER 31, 2016 , 2015 , AND 2014 (In thousands of United States dollars) Year Ended December 31, 2014 Insurance Reinsurance Total Deferred Acquisition Costs $ 34,581 $ 172,787 $ 207,368 Reserve for Losses and Loss Expenses 2,123,772 1,723,087 3,846,859 Unearned Premiums 642,779 611,740 1,254,519 Net Premiums Earned 833,912 1,030,066 1,863,978 Net Investment Income (1) — — 131,543 Net Losses and Loss Expenses 594,561 375,601 970,162 Amortization of Deferred Acquisition Costs 65,368 254,145 319,513 Other Operating Expenses (2) 148,475 98,912 247,387 Net Premiums Written 860,406 1,073,800 1,934,206 (1) Because the Company does not manage its assets by segment, investment income is not allocated to the individual segments. (2) General and administrative expenses incurred by segments are allocated directly. Remaining general and administrative expenses not incurred by the segments are classified as corporate expenses and are not allocated to the individual business segments.

Schedule IV Reinsurance

Schedule IV Reinsurance	12 Months Ended
	Dec. 31, 2016
Supplemental Schedule of Reinsurance Premiums for Insurance Companies [Abstract]
Schedule IV Reinsurance	SCHEDULE IV ENDURANCE SPECIALTY HOLDINGS LTD. AND SUBSIDIARIES REINSURANCE FOR THE YEARS ENDED DECEMBER 31, 2016 , 2015 AND 2014 (In thousands of United States dollars) Premiums Written Gross Amount Ceded to Other Companies Assumed from Other Companies Net Amount Percentage of Amount Assumed to Net Year ended December 31, 2016 Property and liability insurance $ 2,570,494 $ 1,832,235 $ 1,631,676 $ 2,369,935 69 % Year ended December 31, 2015 Property and liability insurance $ 2,085,901 $ 1,370,391 $ 1,234,960 $ 1,950,470 63 % Year ended December 31, 2014 Property and liability insurance $ 1,716,128 $ 959,870 $ 1,177,948 $ 1,934,206 61 %

Schedule V - Valuation and Qual

Schedule V - Valuation and Qualifying Accounts (Notes)	12 Months Ended
	Dec. 31, 2016
Valuation and Qualifying Accounts [Abstract]
Schedule V - Valuation and Qualifying Accounts	SCHEDULE V ENDURANCE SPECIALTY HOLDINGS LTD. AND SUBSIDIARIES VALUATION AND QUALIFYING ACCOUNTS FOR THE YEARS ENDED DECEMBER 31, 2016 , 2015 AND 2014 (In thousands of United States dollars) Balance at Beginning of Year Charged to costs and expenses Charged to other accounts Deductions (1) Balance at End of Year December 31, 2016 Valuation allowance for deferred tax assets 131,138 — — 26,330 104,808 December 31, 2015 Valuation allowance for deferred tax assets 121,409 — 13,300 3,571 131,138 December 31, 2014 Valuation allowance for deferred tax assets 122,680 — — 1,271 121,409 (1) Credited to the related asset account

Schedule VI Underwriters

Schedule VI Underwriters	12 Months Ended
	Dec. 31, 2016
Supplemental Information for Property, Casualty Insurance Underwriters [Abstract]
Schedule of Supplemental Information for Property, Casualty Insurance Underwriters [Text Block]	SCHEDULE VI ENDURANCE SPECIALTY HOLDINGS LTD. AND SUBSIDIARIES SUPPLEMENTARY INFORMATION FOR PROPERTY AND CASUALTY INSURANCE UNDERWRITERS FOR THE YEARS ENDED DECEMBER 31, 2016 , 2015 , AND 2014 (In thousands of United States dollars) Year Ended December 31, 2016 Insurance Reinsurance Total Deferred Acquisition Costs $ 72,502 $ 204,137 $ 276,639 Reserve for Losses and Loss Expenses 2,798,989 2,106,149 4,905,138 Discount if any, Reserve for Losses and Loss Expenses — — — Unearned Premiums 1,124,359 870,317 1,994,676 Net Premiums Earned 1,009,375 1,354,285 2,363,660 Net Investment Income (1) — — 176,590 Net Losses and Loss Expenses Current Year 761,315 781,287 1,542,602 Prior Year (77,137 ) (144,413 ) (221,550 ) Amortization of Deferred Acquisition Costs 149,763 310,720 460,483 Paid Losses and Loss Expenses 592,018 593,872 1,185,890 Net Premiums Written 1,056,254 1,313,681 2,369,935 (1) Because the Company does not manage its assets by segment, investment income is not allocated to the individual segments. Year Ended December 31, 2015 Insurance Reinsurance Total Deferred Acquisition Costs $ 58,216 $ 197,285 $ 255,501 Reserve for Losses and Loss Expenses 2,493,894 2,016,521 4,510,415 Discount if any, Reserve for Losses and Loss Expenses — — — Unearned Premiums 902,152 886,996 1,789,148 Net Premiums Earned 824,552 1,153,901 1,978,453 Net Investment Income (1) — — 113,826 Net Losses and Loss Expenses Current Year 582,868 577,704 1,160,572 Prior Year (82,001 ) (161,463 ) (243,464 ) Amortization of Deferred Acquisition Costs 80,252 267,633 347,885 Paid Losses and Loss Expenses 626,606 507,031 1,133,637 Net Premiums Written 880,373 1,070,097 1,950,470 (1) Because the Company does not manage its assets by segment, investment income is not allocated to the individual segments. SCHEDULE VI ENDURANCE SPECIALTY HOLDINGS LTD. AND SUBSIDIARIES SUPPLEMENTARY INFORMATION FOR PROPERTY AND CASUALTY INSURANCE UNDERWRITERS, Cont’d. FOR THE YEARS ENDED DECEMBER 31, 2016 , 2015 , AND 2014 (In thousands of United States dollars) Year Ended December 31, 2014 Insurance Reinsurance Total Deferred Acquisition Costs $ 34,581 $ 172,787 $ 207,368 Reserve for Losses and Loss Expenses 2,123,772 1,723,087 3,846,859 Discount if any, Reserve for Losses and Loss Expenses — — — Unearned Premiums 642,779 611,740 1,254,519 Net Premiums Earned 833,912 1,030,066 1,863,978 Net Investment Income (1) — — 131,543 Net Losses and Loss Expenses Current Year 675,131 528,846 1,203,977 Prior Year (80,570 ) (153,245 ) (233,815 ) Amortization of Deferred Acquisition Costs 65,368 254,145 319,513 Paid Losses and Loss Expenses 700,576 457,636 1,158,212 Net Premiums Written 860,406 1,073,800 1,934,206 (1) Because the Company does not manage its assets by segment, investment income is not allocated to the individual segments.

Summary Of Significant Accoun34

Summary Of Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Premiums And Related Expenses	(a) Premiums and related expenses The Company's insurance premiums are earned pro rata over the term of the applicable risk period specified in the insurance policy. The Company's insurance policies cover losses occurring or claims made during the term of the policy. Generally, the Company receives a fixed premium which is identified in the policy and is recorded on the inception date of the contract or when premiums are determinable and earned evenly over the policy term. This premium will only adjust if the underlying insured values adjust. Accordingly, the Company monitors the underlying insured values and records additional or return premiums in the period in which amounts are reasonably determinable. The Company's reinsurance premiums are earned in proportion to the amount of reinsurance protection provided over the applicable risk period established in the reinsurance contract. Reinsurance contracts written on a losses occurring basis cover losses which occur during the term of the reinsurance contract, typically 12 months. Accordingly, the Company earns the premium on a losses occurring reinsurance contract evenly over the reinsurance contract term. Reinsurance contracts written on a policies attaching basis cover losses from the underlying insurance policies incepting during the terms of the reinsurance contracts. Losses under a policies attaching reinsurance contract may occur after the end date of the reinsurance contract, so long as they are losses from policies that began during the reinsurance contract period. The Company typically earns the premiums for policies attaching reinsurance contracts over a 24 -month period in proportion to the amount of reinsurance protection provided to reflect the extension of the risk period past the term of the contract and the varying levels of reinsurance protection provided during the reinsurance contract period. In addition to the applicable risk period, the Company's estimate of its reinsurance premiums written is based on the type of reinsurance contracts underwritten. For excess of loss reinsurance contracts, the deposit premium, as defined in the contract, is generally considered to be the best estimate of the reinsurance contract's written premium at inception. The Company earns reinstatement premiums upon the occurrence of a loss under the reinsurance contract. Reinstatement premiums are calculated in accordance with the contract terms based upon the ultimate loss estimate associated with each contract. For proportional reinsurance contracts, the Company estimates premium, commissions and related expenses based on broker and ceding company estimates and also utilizes judgment in establishing proportional reinsurance contract estimates. Premiums on the Company's excess of loss and proportional reinsurance contracts are estimated at the time the business is underwritten. Accordingly, this is the amount the Company records as written premium in the period the reinsurance contract is underwritten. As actual premiums are reported by the ceding companies, management evaluates the appropriateness of the original premium estimates and any adjustments to these estimates are recorded in the period in which they become known. Premiums receivable are recorded at amounts due less any allowance for estimated uncollectible premiums receivable. At December 31, 2016 , the Company had an allowance for estimated uncollectible premiums receivable of $6.2 million ( 2015 - $7.4 million ). Acquisition expenses are costs that vary with and are directly related to the successful production of new and renewal business, and consist principally of commissions and brokerage expenses. Acquisition and general and administrative expenses are shown net of commissions, other fees and expense allowances associated with and earned on ceded business. These costs are deferred and amortized over the periods in which the related premiums are earned. Deferred acquisition costs are limited to their estimated realizable value based on the related unearned premiums. Anticipated net investment income is considered in determining the recoverability of deferred acquisition costs.
Reserve For Losses And Loss Expenses	(b) Reserve for losses and loss expenses The Company’s reserve for losses and loss expenses includes case reserves and reserves for losses incurred but not reported (referred to as "IBNR reserves"). Case reserves are established for losses that have been reported, but not yet paid. IBNR reserves represent a provision for claims that have been incurred but not yet reported to the Company, as well as future loss development on losses already reported, in excess of the case reserves. Case reserves and IBNR reserves are established by management based on reports from reinsurance intermediaries, ceding companies and insureds, and consultations with independent legal counsel. In addition, reserves for IBNR losses and loss expenses are established by management based on reported losses and loss expenses, and actuarially determined estimates of ultimate losses and loss expenses. The Company uses a variety of actuarial methods to estimate the ultimate losses and loss expenses incurred by the Company. One actuarial method used by the Company to estimate reserves for losses and loss expenses is the expected loss ratio approach, which is based on expected results independent of current loss reporting activity. This approach is typically used for immature loss periods (i.e., the current accident year). Another actuarial method used by the Company to estimate reserves for losses and loss expenses is known as the Bornhuetter-Ferguson method. The Bornhuetter-Ferguson method uses an initial loss estimate (expected loss technique) for each accident year by business line and type of contract. Under this method, IBNR is set equal to the initial loss estimate multiplied by the expected percent of loss yet to be reported at each valuation date. In a given quarter, if reported losses are less than expected, then the difference would result in a decrease in estimated ultimate losses. If losses are greater than expected, then the difference would result in an increase in estimated ultimate losses. A third actuarial method used by the Company to estimate reserves for losses and loss expenses is known as the loss development method. The loss development method extrapolates the current value of reported losses to ultimate expected losses by using selected reporting patterns of losses over time. The selected reporting patterns are based on historical information (organized into loss development triangles) and are adjusted to reflect the changing characteristics of the book of business written by the Company. Management uses these multiple actuarial methods, supplemented with professional judgment, to establish the best estimate of reserves for losses and loss expenses. The Company's loss and loss expense reserves are reviewed regularly, and adjustments, if any, are reflected in earnings in the period in which they become known. The establishment of new loss and loss expense reserves or the adjustment of previously recorded loss and loss expense reserves could result in significant positive or negative changes to the Company's financial condition for any particular period. While management believes the Company's estimate of loss and loss expense reserves is reasonable, the ultimate loss experience may not be reliably predicted, and it is possible losses and loss expenses may be materially different than the total reserve for losses and loss expenses recorded by the Company. Reserves for losses and loss expenses are based in part upon the estimation of losses resulting from catastrophic events. Estimation of these losses and loss expenses are based upon the Company's historical claims experience and is inherently difficult because of the Company's short operating history and the possible severity of catastrophe claims. Therefore, the Company uses both proprietary and commercially available models, as well as historical reinsurance industry catastrophe claims experience in addition to its own historical data for purposes of evaluating trends and providing an estimate of ultimate claims costs.
Reinsurance	(c) Reinsurance Reinsurance recoverable on paid and unpaid losses represent estimates of losses and loss expenses that will be recovered from reinsurers. Amounts recoverable from reinsurers are estimated in a manner consistent with the provisions of the reinsurance agreements and consistent with the establishment of the Company's reserve for losses and loss expenses. Ceding commissions earned on ceded business are classified as an offset to acquisition and general and administrative expenses. The Company purchases reinsurance to reduce its exposure to risk of loss in certain insurance and reinsurance lines of business. Reinsurance recoverables are recorded as assets if the reinsurer is deemed able to meet its obligations. Ceded reinsurance contracts do not relieve the Company from its obligations to policyholders. The Company remains primarily liable to its policyholders for the portion reinsured to the extent that any reinsurer does not meet the obligations assumed under the reinsurance agreements.
Investments	(d) Investments The Company currently classifies its fixed maturity investments, short-term investments and equity securities as trading or available for sale. Trading securities are carried at estimated fair value, with related net realized and unrealized gains or losses included in earnings. The Company acquired a portfolio of investments classified as trading from Montpelier. Available for sale securities are carried at estimated fair value, with related net unrealized gains or losses excluded from earnings and included in shareholders' equity as a component of accumulated other comprehensive loss. Investment transactions are recorded on a trade date basis. The Company determines the fair value of its trading and available for sale investments in accordance with current accounting guidance, which defines fair value and establishes a fair value hierarchy based on inputs to the various valuation techniques used for each fair value measurement. The use of valuation techniques for any given investment requires a significant amount of judgment and consideration of factors specific to the underlying investment. Fair value measurements determined by the Company seek to maximize observable inputs and minimize the use of unobservable inputs. 2. Significant accounting policies, cont'd. (d) Investments, cont'd. Current accounting guidance establishes three levels as follows: Level 1: Unadjusted quoted prices in active markets for identical assets or liabilities. Level 2: Quoted prices for similar assets in markets that are active, quoted prices for identical or similar assets in markets that are not active or inputs that are observable either directly or indirectly. Level 2 inputs include quoted prices for similar assets or liabilities other than quoted prices in Level 1; quoted prices in markets that are not active; or other inputs that are observable or can be derived principally from or corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3: Unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities. Unobservable inputs reflect the Company's own views about the assumptions that market participants would use in pricing the asset or liability. Level 3 assets and liabilities include financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation. The Company determines the estimated fair value of each individual security utilizing the highest level inputs available. If the Company has the intent to sell a fixed maturity or short-term security classified as available for sale in an unrealized loss position or it is more likely than not that the Company will be required to sell the available for sale security, the Company deems the security to be other-than-temporarily impaired and writes down the carrying value of the security to fair value, thereby establishing a new cost basis. The amount of the write-down is recognized in earnings as an other-than-temporary impairment ("OTTI") loss. For fixed maturity and short-term investments classified as available for sale in an unrealized loss position for which a decision to sell has not been made and it is not more likely than not that the Company will be required to sell the security, the Company performs additional reviews to determine whether the investment will recover its amortized cost. If the amortized cost of the Company's fixed maturity and short-term investments classified as available for sale is, based upon the judgment of management, unlikely to be recovered, the Company writes down the investment by the amount representing the credit related portion of the decline in value, thereby establishing a new cost basis. The amount of the write-down is recognized in earnings as an OTTI loss. The new cost basis is not changed for subsequent recoveries in fair value. To the extent the Company determines that the amortized cost of the Company's fixed maturity and short-term investments classified as available for sale is likely to be recovered and the decline in value is related to non-credit factors (such as interest rates, market conditions, etc.) and not due to credit related factors, that remaining non-credit portion of the unrealized loss is recorded as a part of accumulated other comprehensive loss in the shareholders' equity section of the Company's Consolidated Balance Sheets. For equity securities classified as available for sale, the Company considers its ability and intent to hold the equity security in an unrealized loss position for a reasonable period of time to allow for a full recovery. When the Company determines that the decline in value of an equity security is other-than-temporary, the Company reduces the cost of the equity security to its fair value and recognizes the loss in the Consolidated Statements of Income and Comprehensive Income. The new cost basis is not changed for subsequent recoveries in fair value. Other investments within the Company's investment portfolio are comprised of hedge funds, private investment funds and other investment funds that generally invest in senior secured bank debt, high yield credit securities, distressed debt, macro strategies, multi-strategy, equity long/short strategies, distressed real estate, and energy sector private equity ("alternative funds"). Other investments are accounted for using the equity method of accounting whereby the initial investment is recorded at cost. The carrying values of these investments are increased or decreased to reflect the Company's share of income or loss, which is included in net investment income, and are decreased for dividends. Due to the timing of the delivery of the final valuations reported by the managers of certain of our alternative funds, our investments in those funds are estimated based on the most recently available information including period end valuation statements, period end estimates, or, in some cases, prior month or quarter valuation statements.
Cash Equivalents And Short-term Investments	(e) Cash equivalents and short-term investments Cash equivalents include highly liquid short-term deposits and securities with maturities of ninety days or less at the time of purchase. Cash equivalents are valued at amortized cost, which approximates fair value due to the short-term, liquid nature of these securities. Deposits and securities with maturities greater than ninety days and less than one year are classified as short-term investments.
Intangible Assets	(f) Intangible assets Identifiable intangible assets are amortized in accordance with their useful lives. Goodwill and intangible assets with indefinite useful lives are not amortized but are tested for impairment annually at the beginning of the fourth quarter, or more often if impairment indicators arise. In making an assessment of the value of its goodwill and intangible assets, the Company uses both market based and non-market based valuations. Assumptions underlying these valuations include forecasts of discounted future cash flows and future profits and comparable transactions observed in the market, in addition to an analysis of the Company’s stock price relative to both its book value and its net income.
Offering And Registration Costs	(g) Offering and registration costs Offering and registration costs incurred in connection with equity offerings, including investment banking fees and legal fees, are deducted from the proceeds of the offerings.
Foreign Exchange	(h) Foreign exchange Assets and liabilities of foreign operations whose functional currency is not the United States dollar are translated at exchange rates in effect at the balance sheet date. Revenues and expenses of such foreign operations are translated at weighted average exchange rates during the year. The effect of the translation adjustments for foreign operations is included in accumulated other comprehensive loss, net of applicable deferred income taxes. Other monetary assets and liabilities denominated in foreign currencies are revalued at the exchange rates in effect at the balance sheet date with the resulting net foreign exchange gains and losses included in earnings. Revenues and expenses denominated in foreign currencies are translated at the prevailing exchange rate on the transaction date.
Derivatives	Derivatives Current accounting guidance requires the recognition of all derivative financial instruments including embedded derivative instruments, as either assets or liabilities in the Consolidated Balance Sheets at fair value. The Company may use various derivative instruments such as foreign exchange forward, future and option contracts; industry loss warranty swaps; interest rate futures, swaps, swaptions, and options; credit default swaps; LIBOR swaps; commodity futures and options; weather swaps and options; loss development covers; and to-be-announced mortgage-backed securities. These derivative instruments are used to manage exposure to interest rate and currency risk, to enhance the efficiency of the Company's investment portfolio, to economically hedge certain risks, and as part of its weather risk management business. Except for a cash flow hedge entered into in 2004 as disclosed in Note 9, Derivatives, these derivative instruments do not qualify, and are not designated, as hedges. Derivatives are recorded at fair value with changes in fair value and any gains or losses are recognized in net realized and unrealized (losses) gains, net foreign exchange (gains) losses, or other underwriting loss in the Consolidated Statements of Income and Comprehensive Income. Where the Company has entered into master netting agreements with counterparties, or the Company has the legal and contractual right to offset positions, the derivative positions may be netted by the counterparty.
Income Taxes	(j) Income taxes The Company accounts for income taxes for its subsidiaries operating in taxable jurisdictions. Deferred income taxes reflect the net tax effect of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. A valuation allowance is provided when it is more likely than not that some portion of the deferred tax assets will not be realized. The accounting guidance allows for the recognition of tax benefits of uncertain tax positions only where the position is more likely than not to be sustained assuming examination by tax authorities. A liability is established for any tax benefit claimed in a tax return in excess of this threshold. Income tax related interest and penalties are included as income tax expense.
Stock Compensation And Other Stock Plans	(k) Stock compensation and other stock plans The Company has a share-based employee and non-employee director equity incentive plan ("2007 Equity Incentive Plan") and other share plans, which are described more fully in Note 16, Stock-based employee compensation and other stock plans. The fair value of the compensation cost incurred under these plans is measured at the grant date and is expensed over the period for which the employee is required to provide services in exchange for the award. Forfeiture benefits are estimated at the time of grant and incorporated in the determination of share-based compensation costs. Awards under the 2007 Equity Incentive Plan generally vest over four years for employees and one year for non-employee directors. The Company uses the Black-Scholes-Merton formula to estimate the value of stock options granted. The fair value of the performance-based restricted shares is measured at the grant date using a Monte Carlo simulation based on pre-established targets relating to certain performance based measures achieved by the Company, with the associated expense recognized over the applicable performance and vesting period. The fair value of the restricted shares granted is equal to the fair market value of the Company's ordinary shares on the grant date. Compensation equal to the fair market value of the restricted shares at the measurement date is amortized and charged to income over the vesting period.
Earnings Per Share	(l) Earnings per share The two-class method utilized by the Company is an earnings allocation formula that determines earnings per share for the holders of Endurance Holdings' ordinary shares (also referred to as "common shares") and participating common shares, which includes unvested restricted shares and restricted share units that receive cash dividends, according to dividends declared (or accumulated) and participation rights in undistributed earnings. Net income available to common and participating common shareholders is reduced by the amount of dividends declared in the current period and by the contractual amount of dividends that must be paid for the current period related to the Company's common and participating common shares. Any remaining undistributed earnings are allocated to the common and participating common shareholders to the extent that each security may share in earnings as if all of the earnings for the period had been distributed. In periods of loss, no losses are allocated to participating common shareholders. Instead, all such losses are allocated solely to the common shareholders. Basic earnings per common share are calculated by dividing net income available to common shareholders by the weighted average number of common shares outstanding. The weighted average number of common shares excludes any dilutive effect of outstanding options and convertible securities such as unvested restricted shares and restricted share units. Diluted earnings per common share are based on the weighted average number of common shares and assumes the exercise of all dilutive stock options and the vesting or conversion of all convertible securities such as unvested restricted shares using the two-class method described above.
Use Of Estimates	(m) Use of estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported and disclosed amounts 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. Actual results could differ from those estimates.
Variable Interest Entity	Entities that do not have sufficient equity at risk to allow the entity to finance its activities without additional financial support or in which the equity investors, as a group, do not have the characteristic of a controlling financial interest are referred to as variable interest entities ("VIE"). A VIE is consolidated by the variable interest holder that is determined to have the controlling financial interest (primary beneficiary) as a result of having both the power to direct the activities of a VIE that most significantly impact the VIE's economic performance and the obligation to absorb losses or right to receive benefits from the VIE that could potentially be significant to the VIE. The Company determines whether it is the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the VIE's capital structure, contractual terms, nature of the VIE's operations and purpose and the Company's relative exposure to the related risks of the VIE on the date it becomes initially involved in the VIE. The Company reassesses its VIE determination with respect to an entity on an ongoing basis. Other Investments The Company is involved in the normal course of business with VIEs primarily as a passive investor in residential and commercial mortgage-backed securities and through its interests in various other investments that are structured as limited partnerships considered to be third party VIEs. The Company determines whether it is the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the VIE's capital structure, contractual terms, nature of the VIE's operations and purpose, and the Company's relative exposure to the related risks of the VIE on the date it becomes initially involved in the VIE. The Company determined that it was not the primary beneficiary for any of these investments as of December 31, 2016 and 2015 . The Company believes its exposure to loss with respect to these investments is generally limited to the investment carrying amounts reported in the Company's Consolidated Balance Sheets and any unfunded investment commitments. 4. Investments, cont'd. Collateralized Reinsurance Entities As of December 31, 2016 , Endurance Holdings and Endurance Bermuda together owned 33.3% of BCRH. BCRH is considered a VIE under U.S. GAAP and the Company has determined that it is BCRH's primary beneficiary. As a result, the Company fully consolidates the assets, liabilities and operations of BCRH and its subsidiaries within its Consolidated Financial Statements. The interests in BCRH and its subsidiaries that the Company fully consolidates that are attributable to third-party investors are reported within the Company's Consolidated Financial Statements as non-controlling interests. BCRH's shareholder rights do not include redemption features within the control of the third party shareholders. The Company reassesses its VIE determination with respect to BCRH on an ongoing basis. As of December 31, 2016 , Endurance Bermuda owned 25.2% of BCGR. BCGR is considered a "voting interest entity" under U.S. GAAP and, because the Company owns less than 50% of its outstanding ordinary shares, the Company does not consolidate BCGR's assets, liabilities or operations within its Consolidated Financial Statements. However, the BCGR Cell and Blue Water Re, the Company's wholly-owned Bermuda-based special purpose insurance vehicle, are considered VIEs under U.S. GAAP and the Company has determined that it is the primary beneficiary of these entities. Therefore, as funds held in BCGR are deployed into the BCGR Cell, and ultimately into Blue Water Re, they are included in the Company's consolidated financial statements. Conversely, as funds previously deployed by BCGR and the BCGR Cell into Blue Water Re are returned to BCGR, they are no longer included in the Company's consolidated financial statements. The interests in the BCGR Cell and Blue Water Re that the Company fully consolidate that are attributable to third-party investors are reported within the Company's consolidated financial statements as non-controlling interests. BCGR's shareholder rights do not include redemption features within the control of the third party shareholders. The Company reassesses its VIE determinations with respect to the BCGR Cell and Blue Water Re on an ongoing basis.
Non-controlling interests	(o) Non-controlling interests The Company accounts for non-controlling interests in the shareholders' equity section of the Company's Consolidated Balance Sheets in accordance with current accounting guidance regarding consolidation. Net income attributable to non-controlling interest is presented separately in the Company's Consolidated Statements of Income and Comprehensive Income.
Reclassifications	(p) Reclassifications Certain comparative information has been reclassified to conform to current year presentation.
Recent Accounting Pronouncements	(q) Recent accounting pronouncements In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2014-09, "Revenue from Contracts with Customers" ("ASU 2014-09"). ASU 2014-09 provides comprehensive guidance on the recognition of revenue from customers arising from the transfer of goods and services. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for these goods or services. ASU 2014-09 also provides guidance on accounting for certain contract costs and will also require new disclosures. ASU 2014-09 was to be effective for public business entities in annual and interim periods beginning after December 15, 2016, however, in July 2015, the FASB decided to defer by one year the effective dates of ASU 2014-09, and as a result, ASU 2014-09 will be effective for public business entities in annual and interim period beginning after December 15, 2017. Early adoption is permitted. Based on initial review, the Company has determined that this standard specifically excludes revenue from the following sources: insurance contracts, Topic 944, Financial Services-Insurance and investment income; Topic 320, Investments-Debt and Equity Securities; Topic 323, Investments-Equity Methods and Joint Ventures; Topic 325, Investment-Others; and Topic 815, Derivatives and Hedging. As substantially all of the Company's revenues are subject to the topics above that are excluded from the standard, the Company has determined that this standard will not have a material impact on the Company's Consolidated Financial Statements. In February 2015, the FASB issued ASU 2015-02, "Amendments to the Consolidation Analysis" ("ASU 2015-02"). Under ASU 2015-02, all legal entities are required to evaluate whether they should consolidate certain legal entities. ASU 2015-02 set forth amendments: (1) modifying the evaluation of whether limited partnerships and similar legal entities are VIEs or voting interest entities; (2) eliminating the presumption that a general partner should consolidate a limited partnership; (3) affecting the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships; and (4) providing a scope exception from consolidation guidance for certain reporting entities. ASU 2015-02 was effective for public business entities for annual and interim periods beginning after December 15, 2015. Early adoption was permitted. ASU 2015-02 may be applied retrospectively or by using a modified retrospective approach by recording a cumulative-effect adjustment to equity as of the beginning of the year of adoption. The Company adopted this standard on January 1, 2016 and it did not have a material impact on the Company's Consolidated Financial Statements. 2. Significant accounting policies, cont'd. (q) Recent accounting pronouncements, cont'd. In May 2015, the FASB issued ASU 2015-09, "Disclosures about Short-Duration Contracts" ("ASU 2015-09"). The objective of ASU 2015-09 is to make targeted improvements to disclosure requirements for insurance companies that issue short-duration contracts. The guidance requires additional disclosures of claims development tables, frequency of reported claims, and history of claims duration. This information is required to be disaggregated so that useful information is not obscured by either the inclusion of a large amount of insignificant detail, or the aggregation of items that have significantly different characteristics. ASU 2015-09 was effective for public business entities in annual periods beginning after December 15, 2015, and interim periods within annual periods beginning after December 15, 2016. Early adoption was permitted. ASU 2015-09 should be applied retrospectively. The Company adopted this standard in the fourth quarter of 2016 and has included the appropriate annual disclosures within Note 6, Reserve for losses and loss expenses. The adoption of this standard did not have a material impact on the Company's Consolidated Financial Statements. In January 2016, the FASB issued ASU No. 2016-01, "Recognition and Measurement of Financial Assets and Financial Liabilities" ("ASU 2016-01"). ASU 2016-01 requires equity investments (except those accounted for under the equity method of accounting or those that result in the consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income, simplifies the impairment assessment of equity investments without readily determinable values by requiring a qualitative assessment to identify impairment, eliminates the requirement to disclose the methods and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost, requires the use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes, requires separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the organization has elected to measure the liabilities in accordance with the fair value option, requires the separate presentation of financial assets and financial liabilities by measurement category and for form of years, beginning after December 15, 2015. Early adoption was permitted. The Company adopted ASU 2015-02 effective January 1, 2016 and it did not have material impact on the Company's consolidated statements of operations and financial position.

Investments (Policy)

Investments (Policy)	12 Months Ended
	Dec. 31, 2016
Investments [Abstract]
Other Investments	In addition to the Company's fixed maturity, short-term and equity investments, the Company invests in alternative funds. The Company's alternative funds are recorded on the Company's balance sheet as "other investments".
Gain Loss On Investments	Realized and unrealized gains and losses are recognized in earnings using the first in, first out method.
Variable Interest Entity	Entities that do not have sufficient equity at risk to allow the entity to finance its activities without additional financial support or in which the equity investors, as a group, do not have the characteristic of a controlling financial interest are referred to as variable interest entities ("VIE"). A VIE is consolidated by the variable interest holder that is determined to have the controlling financial interest (primary beneficiary) as a result of having both the power to direct the activities of a VIE that most significantly impact the VIE's economic performance and the obligation to absorb losses or right to receive benefits from the VIE that could potentially be significant to the VIE. The Company determines whether it is the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the VIE's capital structure, contractual terms, nature of the VIE's operations and purpose and the Company's relative exposure to the related risks of the VIE on the date it becomes initially involved in the VIE. The Company reassesses its VIE determination with respect to an entity on an ongoing basis. Other Investments The Company is involved in the normal course of business with VIEs primarily as a passive investor in residential and commercial mortgage-backed securities and through its interests in various other investments that are structured as limited partnerships considered to be third party VIEs. The Company determines whether it is the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the VIE's capital structure, contractual terms, nature of the VIE's operations and purpose, and the Company's relative exposure to the related risks of the VIE on the date it becomes initially involved in the VIE. The Company determined that it was not the primary beneficiary for any of these investments as of December 31, 2016 and 2015 . The Company believes its exposure to loss with respect to these investments is generally limited to the investment carrying amounts reported in the Company's Consolidated Balance Sheets and any unfunded investment commitments. 4. Investments, cont'd. Collateralized Reinsurance Entities As of December 31, 2016 , Endurance Holdings and Endurance Bermuda together owned 33.3% of BCRH. BCRH is considered a VIE under U.S. GAAP and the Company has determined that it is BCRH's primary beneficiary. As a result, the Company fully consolidates the assets, liabilities and operations of BCRH and its subsidiaries within its Consolidated Financial Statements. The interests in BCRH and its subsidiaries that the Company fully consolidates that are attributable to third-party investors are reported within the Company's Consolidated Financial Statements as non-controlling interests. BCRH's shareholder rights do not include redemption features within the control of the third party shareholders. The Company reassesses its VIE determination with respect to BCRH on an ongoing basis. As of December 31, 2016 , Endurance Bermuda owned 25.2% of BCGR. BCGR is considered a "voting interest entity" under U.S. GAAP and, because the Company owns less than 50% of its outstanding ordinary shares, the Company does not consolidate BCGR's assets, liabilities or operations within its Consolidated Financial Statements. However, the BCGR Cell and Blue Water Re, the Company's wholly-owned Bermuda-based special purpose insurance vehicle, are considered VIEs under U.S. GAAP and the Company has determined that it is the primary beneficiary of these entities. Therefore, as funds held in BCGR are deployed into the BCGR Cell, and ultimately into Blue Water Re, they are included in the Company's consolidated financial statements. Conversely, as funds previously deployed by BCGR and the BCGR Cell into Blue Water Re are returned to BCGR, they are no longer included in the Company's consolidated financial statements. The interests in the BCGR Cell and Blue Water Re that the Company fully consolidate that are attributable to third-party investors are reported within the Company's consolidated financial statements as non-controlling interests. BCGR's shareholder rights do not include redemption features within the control of the third party shareholders. The Company reassesses its VIE determinations with respect to the BCGR Cell and Blue Water Re on an ongoing basis.

Fair Value Measurement (Policy)

Fair Value Measurement (Policy)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Of Financial Instruments	The Company determines the fair value of its fixed maturity investments, short-term investments, equity securities, debt, and other assets and liabilities in accordance with current accounting guidance, which defines fair value and establishes a fair value hierarchy based on inputs to the various valuation techniques used for each fair value measurement. The Company determines the estimated fair value of each individual security utilizing the highest level inputs available. Valuation inputs by security type may include the following: • Government and agencies fixed maturity securities – These securities are generally priced by pricing services or index providers. The pricing services or index providers may use current market trades for securities with similar quality, maturity and coupon. If no such trades are available, the pricing service typically uses analytical models which may incorporate option adjusted spreads, daily interest rate data and market/sector news. The Company generally classifies the fair values of government and agencies securities in Level 2. Current issue U.S. government securities are generally valued based on Level 1 inputs, which use the market approach valuation technique. • Government guaranteed corporate fixed maturity securities – These securities are generally priced by pricing services or index providers. The pricing service or index providers may use current market trades for securities with similar quality, maturity and coupon. If no such trades are available, the pricing service typically uses analytical spread models which may incorporate inputs from the U.S. treasury curve or LIBOR. The Company generally classifies the fair values of its government guaranteed corporate securities in Level 2. • Corporate fixed maturity securities – These securities are generally priced by pricing services or index providers. The pricing services or index providers typically use discounted cash flow models that incorporate benchmark curves for treasury, swap and high issuance credits. Credit spreads are developed from current market observations for like or similar securities. The Company generally classifies the fair values of its corporate securities in Level 2. • Equity securities – These securities are generally priced by pricing services or index providers. Depending on the type of underlying equity security or equity fund, the securities are priced by pricing services or index providers based on quoted market prices in active markets or through a discounted cash flow model that incorporates benchmark curves for treasury, swap and credit for like or similar securities. The Company generally classifies the fair values of its equity securities in Level 1 or 2. • Structured securities including agency and non-agency, residential and commercial mortgage, asset-backed securities and collateralized loan and debt obligations – These securities are generally priced by broker/dealers. Broker/dealers may use current market trades for securities with similar qualities. If no such trades are available, inputs such as bid and offer, prepayment speeds, the U.S. treasury curve, swap curve and cash settlement may be used in a discounted cash flow model to determine the fair value of a security. The Company generally classifies the fair values of its structured securities in Level 2. • Other assets and liabilities – A portion of other assets and liabilities are composed of a variety of derivative instruments used to enhance the efficiency of the investment portfolio and economically hedge certain risks. These instruments are generally priced by pricing services, broker/dealers and/or recent trading activity. The market value approach valuation technique is used to estimate the fair value for these derivatives based on significant observable market inputs. Certain derivative instruments are priced by pricing services based on quoted market prices in active markets. These derivative instruments are generally classified in Level 1. Other derivative instruments are priced using industry valuation models and are considered Level 2, as the inputs to the valuation model are based on observable market inputs. Also included in this line item are proprietary, non-exchange traded derivative-based risk management products primarily used to address weather and energy risks. The trading market for these weather derivatives are generally linked to energy and agriculture commodities, weather and other natural phenomena. In instances where market prices are not available, the Company uses industry or internally developed valuation techniques such as spread option, Black Scholes, quanto and simulation modeling to determine fair value and classifies these in Level 3. These models may reference prices for similar instruments. • Debt – Outstanding debt consists of the Company's 7% Senior Notes due July 15, 2034 and 4.7% Senior Notes due October 15, 2022 (the "Senior Notes") and the Trust Preferred Securities. The fair values of these securities were obtained from a third party pricing service and pricing was based on the spread above the risk-free yield curve. These spreads are generally obtained from the new issue market, secondary trading and broker-dealer quotes. As these spreads and the yields for the risk-free yield curve are observable market inputs, the fair values of the Senior Notes and the Trust Preferred Securities are classified in Level 2. 5. Fair value measurement, cont'd. The carrying values of cash and cash equivalents, accrued investment income, other investments, net receivable on sales of investments, net payable on purchases of investments, the amount outstanding under the BCRH Credit Agreement and other financial instruments not described above approximated their fair values at December 31, 2016 and 2015 .

Reserve For Losses And Loss E37

Reserve For Losses And Loss Expenses (Policy)	12 Months Ended
	Dec. 31, 2016
Insurance Loss Reserves [Abstract]
Reserve For Losses And Loss Expenses	(b) Reserve for losses and loss expenses The Company’s reserve for losses and loss expenses includes case reserves and reserves for losses incurred but not reported (referred to as "IBNR reserves"). Case reserves are established for losses that have been reported, but not yet paid. IBNR reserves represent a provision for claims that have been incurred but not yet reported to the Company, as well as future loss development on losses already reported, in excess of the case reserves. Case reserves and IBNR reserves are established by management based on reports from reinsurance intermediaries, ceding companies and insureds, and consultations with independent legal counsel. In addition, reserves for IBNR losses and loss expenses are established by management based on reported losses and loss expenses, and actuarially determined estimates of ultimate losses and loss expenses. The Company uses a variety of actuarial methods to estimate the ultimate losses and loss expenses incurred by the Company. One actuarial method used by the Company to estimate reserves for losses and loss expenses is the expected loss ratio approach, which is based on expected results independent of current loss reporting activity. This approach is typically used for immature loss periods (i.e., the current accident year). Another actuarial method used by the Company to estimate reserves for losses and loss expenses is known as the Bornhuetter-Ferguson method. The Bornhuetter-Ferguson method uses an initial loss estimate (expected loss technique) for each accident year by business line and type of contract. Under this method, IBNR is set equal to the initial loss estimate multiplied by the expected percent of loss yet to be reported at each valuation date. In a given quarter, if reported losses are less than expected, then the difference would result in a decrease in estimated ultimate losses. If losses are greater than expected, then the difference would result in an increase in estimated ultimate losses. A third actuarial method used by the Company to estimate reserves for losses and loss expenses is known as the loss development method. The loss development method extrapolates the current value of reported losses to ultimate expected losses by using selected reporting patterns of losses over time. The selected reporting patterns are based on historical information (organized into loss development triangles) and are adjusted to reflect the changing characteristics of the book of business written by the Company. Management uses these multiple actuarial methods, supplemented with professional judgment, to establish the best estimate of reserves for losses and loss expenses. The Company's loss and loss expense reserves are reviewed regularly, and adjustments, if any, are reflected in earnings in the period in which they become known. The establishment of new loss and loss expense reserves or the adjustment of previously recorded loss and loss expense reserves could result in significant positive or negative changes to the Company's financial condition for any particular period. While management believes the Company's estimate of loss and loss expense reserves is reasonable, the ultimate loss experience may not be reliably predicted, and it is possible losses and loss expenses may be materially different than the total reserve for losses and loss expenses recorded by the Company. Reserves for losses and loss expenses are based in part upon the estimation of losses resulting from catastrophic events. Estimation of these losses and loss expenses are based upon the Company's historical claims experience and is inherently difficult because of the Company's short operating history and the possible severity of catastrophe claims. Therefore, the Company uses both proprietary and commercially available models, as well as historical reinsurance industry catastrophe claims experience in addition to its own historical data for purposes of evaluating trends and providing an estimate of ultimate claims costs.

Reinsurance (Policy)

Reinsurance (Policy)	12 Months Ended
	Dec. 31, 2016
Reinsurance Transactions [Abstract]
Reinsurance	(c) Reinsurance Reinsurance recoverable on paid and unpaid losses represent estimates of losses and loss expenses that will be recovered from reinsurers. Amounts recoverable from reinsurers are estimated in a manner consistent with the provisions of the reinsurance agreements and consistent with the establishment of the Company's reserve for losses and loss expenses. Ceding commissions earned on ceded business are classified as an offset to acquisition and general and administrative expenses. The Company purchases reinsurance to reduce its exposure to risk of loss in certain insurance and reinsurance lines of business. Reinsurance recoverables are recorded as assets if the reinsurer is deemed able to meet its obligations. Ceded reinsurance contracts do not relieve the Company from its obligations to policyholders. The Company remains primarily liable to its policyholders for the portion reinsured to the extent that any reinsurer does not meet the obligations assumed under the reinsurance agreements.

Derivatives (Policy)

Derivatives (Policy)	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Accounting policy for derivatives	The interest rate lock agreement was designated as a "cash flow hedge" under current accounting guidance and accordingly, the fair value of the derivative was recorded in other comprehensive (loss) income and is being recognized as a component of interest expense in the Consolidated Statements of Income and Comprehensive Income as the interest expense related to the 7% Senior Notes affects earnings. These loans are fully collateralized, are generally outstanding for a short period of time and are presented as part of cash and cash equivalents in the Consolidated Balance Sheets. None of the Company's derivatives are designated as hedges under current accounting guidance, with the exception of the interest rate lock. The Company's objectives for holding these derivatives are as follows: Interest Rate Futures, Swaps, Swaptions and Options - to manage exposure to interest rate risk, which can include increasing or decreasing its exposure to this risk through modification of the portfolio composition and duration. Industry Loss Warranty ("ILW") Swaps - to manage underwriting risk. The Company has entered into ILW swap contracts which provide reinsurance-like protection to the Company for specific loss events associated with certain lines of its business. The Company has also sold ILW protection, which provides reinsurance-like protection to third parties for specific loss events. Foreign Exchange Forwards, Futures and Options - as part of its overall currency risk management and investment strategies. Credit Default Swaps - to manage market exposures. The Company may assume or economically hedge credit risk through credit default swaps to replicate or hedge investment positions. The original term of these credit default swaps is generally five years or less. To-Be-Announced Mortgage-backed Securities (“TBAs”) - to enhance investment performance and as part of the overall investment strategy. TBAs represent commitments to purchase or sell a future issuance of agency mortgage-backed securities. For the period between the purchase of a TBA and issuance of the underlying securities, the Company’s position is accounted for as a derivative. Energy and Weather Contracts - to address weather and energy risks. The Company may purchase or sell contracts with financial settlements based on the performance of an index linked to a quantifiable weather element, such as temperature, precipitation, snowfall or windspeed, and structures with multiple risk triggers indexed to a quantifiable weather element and a weather sensitive commodity price, such as temperature and electrical power or natural gas. Generally, the Company’s current portfolio of energy and weather derivative contracts is of comparably short duration and such contracts are predominantly seasonal in nature. LIBOR Swap – to establish future net cash flows in connection with the Trust Preferred Securities for the 5 -year period beginning March 30, 2012 as if these securities bore interest at a fixed rate of 4.905% . See Note 8, Debt and financing arrangements. Loss Development Cover – as part of the sale of Montpelier U.S. Insurance Company ("MUSIC") to Selective Insurance Group, Inc. ("Selective"), Montpelier Reinsurance Ltd. ("Montpelier Re", now Endurance Bermuda) entered into a loss development cover with MUSIC which ensures that MUSIC's reserve for losses and loss expenses relating to retained business written on or prior to December 31, 2011 remains adequate. Under the loss development cover, any future adverse development associated with such retained reserves will be protected by Endurance Bermuda and any future favorable development associated with such retained reserves will benefit Endurance Bermuda.
Offsetting of derivatives policy	At December 31, 2016 and 2015 , the Company's derivative instruments were recorded on a gross basis in the Consolidated Balance Sheets.

Segment Reporting (Policy)

Segment Reporting (Policy)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment Reporting	The Company attributes gross premiums written to the geographic region in which the risks originate. The determination of the Company's business segments is based on how the Company monitors the performance of its underwriting operations. The Company has two reportable business segments, Insurance and Reinsurance. • Insurance – This segment is comprised of four lines of business: agriculture, casualty and other specialty, professional lines, and property, marine/energy and aviation. The agriculture line of business is comprised of multi-peril crop insurance, crop hail, livestock risk protection and other agriculture risk management products. The casualty and other specialty line of business is comprised of the insurance and facultative reinsurance of third party liability exposures, including casualty and healthcare liability. The professional line of business includes directors' and officers' liability, errors and omissions, employment practices liability, environmental liability and pension trust liability insurance. The property, marine/energy and aviation line of business is comprised of the insurance and facultative reinsurance of commercial properties, inland marine and ocean marine insurance, energy insurance, and general liability and property coverages for a wide range of general aviation risks. • Reinsurance – This segment is comprised of five lines of business: catastrophe, property, casualty, professional lines, and specialty. The catastrophe line of business includes reinsurance for catastrophic perils on a treaty basis. The property line of business includes proportional and excess of loss reinsurance of personal and commercial exposures. The casualty line of business is comprised of third party liability exposures, clash and workers' compensation coverages. The professional line of business includes directors' and officers' liability, errors and omissions, employment practices liability, environmental liability and pension trust liability reinsurance. The specialty line of business includes the reinsurance of aviation and space business and proportional and non-proportional reinsurance of hull and cargo insurance business, and proportional and excess of loss coverages of contract and commercial surety business, personal accident coverages, political risk coverages, weather risk management products and agriculture coverages for weather related perils as well as protection from yield and price risks. 10. Segment reporting, cont'd. Management measures Insurance and Reinsurance segment results on the basis of the combined ratio, which is obtained by dividing the sum of the net losses and loss expenses, acquisition expenses and general and administrative expenses by net premiums earned. When purchased within a single line of business, ceded reinsurance and recoveries are accounted for within that line of business. When purchased across multiple lines of business, ceded reinsurance and recoveries are allocated to the lines of business in proportion to the related risks assumed. The Company does not manage its assets by segment; accordingly, investment income and total assets are not allocated to the individual business segments. General and administrative expenses incurred by segments are allocated directly. Remaining general and administrative expenses not incurred by the segments are classified as corporate expenses and are not allocated to the individual business segments. Ceded reinsurance and recoveries are recorded within the business segment to which they apply. The underwriting results of Montpelier are included in the Company's segment results from August 1, 2015.

Goodwill And Intangible Assets

Goodwill And Intangible Assets Goodwill And Intangible Assets (Policies)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	(f) Intangible assets Identifiable intangible assets are amortized in accordance with their useful lives. Goodwill and intangible assets with indefinite useful lives are not amortized but are tested for impairment annually at the beginning of the fourth quarter, or more often if impairment indicators arise. In making an assessment of the value of its goodwill and intangible assets, the Company uses both market based and non-market based valuations. Assumptions underlying these valuations include forecasts of discounted future cash flows and future profits and comparable transactions observed in the market, in addition to an analysis of the Company’s stock price relative to both its book value and its net income.

Stock-Based Employee Compensa42

Stock-Based Employee Compensation And Other Stock Plans (Policy)	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share Based Compensation RSU Plans [Policy]	The fair value of the restricted share units granted or assumed is equal to the fair market value of the Company's ordinary shares on the grant or assumption date, as applicable. Compensation equal to the fair market value of the restricted share units at the measurement date is amortized and charged to income over the vesting period.
Stock Compensation And Other Stock Plans	(k) Stock compensation and other stock plans The Company has a share-based employee and non-employee director equity incentive plan ("2007 Equity Incentive Plan") and other share plans, which are described more fully in Note 16, Stock-based employee compensation and other stock plans. The fair value of the compensation cost incurred under these plans is measured at the grant date and is expensed over the period for which the employee is required to provide services in exchange for the award. Forfeiture benefits are estimated at the time of grant and incorporated in the determination of share-based compensation costs. Awards under the 2007 Equity Incentive Plan generally vest over four years for employees and one year for non-employee directors. The Company uses the Black-Scholes-Merton formula to estimate the value of stock options granted. The fair value of the performance-based restricted shares is measured at the grant date using a Monte Carlo simulation based on pre-established targets relating to certain performance based measures achieved by the Company, with the associated expense recognized over the applicable performance and vesting period. The fair value of the restricted shares granted is equal to the fair market value of the Company's ordinary shares on the grant date. Compensation equal to the fair market value of the restricted shares at the measurement date is amortized and charged to income over the vesting period.

Acquisition of Montpelier (Tabl

Acquisition of Montpelier (Tables)	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The Company's total purchase price for Montpelier at July 31, 2015 was calculated as follows: Consideration paid by Endurance Holdings Number of Montpelier common shares outstanding immediately prior to the closing of the acquisition 43,827,753 Exchange ratio 0.472 Total Company ordinary shares 20,686,699 Company ordinary share closing price on July 31, 2015 $ 69.49 Total value of Company ordinary shares $ 1,437,519 Fair value of restricted share units attributable to service period prior to Closing Date (1) $ 33,327 Total consideration $ 1,470,846 Special Dividend paid by Montpelier Number of Montpelier common shares and restricted share units eligible for special dividend 45,611,810 Special dividend paid per Montpelier common share and restricted share unit $ 9.89 Total special dividend consideration paid to Montpelier common shareholders and Montpelier equity award holders $ 451,101 Total consideration received by Montpelier common shareholders and Montpelier equity award holders $ 1,921,947 Less: Special Dividend paid by Montpelier (451,101 ) Net purchase price $ 1,470,846 (1) Outstanding Montpelier restricted share units were assumed by the Company and adjusted as of the Closing Date to represent the right to receive 0.472 Company ordinary shares for each outstanding Montpelier restricted share unit rounded down to the next whole number of Company ordinary shares. The fair value of the Montpelier restricted share units was determined based on the closing price of the Company's ordinary shares on the Closing Date. The resulting fair value of the restricted share units was apportioned as purchase consideration based on service provided to Montpelier as of the Closing Date with the remaining fair value of these restricted share units to be recognized prospectively over the restricted share units' remaining vesting period. The following table summarizes the results of Montpelier since July 31, 2015 that have been included in the Company's Consolidated Statement of Income and Comprehensive Income for the year ended December 31, 2015 : For the period from July 31, 2015 to December 31, 2015 Total revenues $ 225,899 Net income attributable to the Company's common shareholders (1) 54,768 (1) Includes $52.7 million of compensation-related costs associated with terminating employees of Montpelier.
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The Company identified finite lived intangible assets of $293.2 million , which will be amortized over a weighted average period of 8 years, identifiable indefinite lived intangible assets of $57.6 million , and certain other adjustments to the fair values of the assets acquired, liabilities assumed and shareholders' equity of Montpelier at July 31, 2015 as summarized in the table below: Montpelier shareholders' equity attributable to controlling interest prior to Special Dividend $ 1,560,255 Cash and cash equivalents (Special Dividend on Montpelier common shares and Montpelier equity awards) (451,101 ) Adjusted shareholders' equity of Montpelier as of July 31, 2015 1,109,154 Adjustments for fair value, by applicable balance sheet caption: Assets: Fixed maturity investments, trading at fair value (11,100 ) Deferred acquisition costs (91,713 ) Reinsurance recoverable on unpaid losses (675 ) Other assets (12,459 ) Liabilities: Reserve for losses and loss expenses 10,822 Debt 21,123 Deferred tax liability (18,346 ) Equity: Non-controlling interest 25,615 Total adjustments for fair value by applicable balance sheet caption (76,733 ) Adjustments for fair value of the identifiable intangible assets: Identifiable indefinite lived intangible assets (insurance licenses, Lloyd's syndicate capacity and asset management agreements) 57,600 Identifiable finite lived intangible assets (non-contractual relationships, Lloyd's syndicate distribution channel, renewal rights, value of business acquired ("VOBA"), trade names, non-compete agreements and asset management agreements) 293,200 Total adjustments for fair value by applicable balance sheet caption and identifiable intangible assets 274,067 Estimated fair value of net assets acquired and identifiable intangible assets 1,383,221 Total consideration paid by Endurance Holdings 1,470,846 Estimated total consideration over the fair value of net assets acquired assigned to goodwill $ 87,625
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block]	Identifiable intangible assets at July 31, 2015 consisted of the following, and are included in goodwill and other intangible assets on the Company's consolidated balance sheets: Amount Economic Useful Life Key non-contractual relationships $ 71,800 10 Other non-contractual relationships 22,400 3 Trade names 1,800 Various Insurance licenses 1,900 Indefinite Non-compete agreements 5,700 Various Lloyd's syndicate capacity 48,300 Indefinite Lloyd's syndicate distribution channel 18,400 10 Renewal rights 82,100 15 VOBA 88,400 2 Asset management agreements 10,000 Various Identifiable intangible assets at July 31, 2015 $ 350,800
Business Acquisition, Pro Forma Information [Table Text Block]	The following table presents unaudited pro forma consolidated financial information for the years ended December 31, 2015 and 2014 and assumes the acquisition of Montpelier occurred on January 1, 2014. The unaudited pro forma consolidated financial information is provided for informational purposes only and is not necessarily, and should not be assumed to be, an indication of the results that would have been achieved had the transaction been completed as of January 1, 2014 or that may be achieved in the future. The unaudited pro forma consolidated financial information does not give consideration to the impact of possible revenue enhancements, expense efficiencies, synergies or asset dispositions that may result from the acquisition of Montpelier. In addition, unaudited pro forma consolidated financial information does not include the effects of costs associated with any restructuring or integration activities resulting from the acquisition of Montpelier, as they are nonrecurring. Year Ended December 31, 2015 2014 Total revenues $ 2,452,410 $ 2,668,604 Net income available to Endurance Holdings' common shareholders 443,817 388,371

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2016
Investments [Abstract]
Composition Of Net Investment Income	The components of net investment income for the years ended December 31, 2016 , 2015 and 2014 are as follows: 2016 2015 2014 Fixed income investments $ 165,210 $ 132,786 $ 118,084 Equity securities 12,639 8,209 5,689 Other investments 12,442 (13,553 ) 19,609 Cash and cash equivalents 2,824 2,870 2,445 $ 193,115 $ 130,312 $ 145,827 Investment expenses (16,525 ) (16,486 ) (14,284 ) Net investment income $ 176,590 $ 113,826 $ 131,543
Contractual Maturities Of Fixed Maturity And Short-Term Investments	Contractual maturities of the Company's fixed maturity and short-term investments are shown below as of December 31, 2016 and 2015 . Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. December 31, 2016 December 31, 2015 Amortized Cost Fair Value Amortized Cost Fair Value Due within one year $ 617,655 $ 617,462 $ 622,070 $ 622,248 Due after one year through five years 2,170,111 2,187,173 2,005,456 1,995,502 Due after five years through ten years 887,775 896,388 683,147 676,932 Due after ten years 55,400 58,449 33,168 34,651 Residential mortgage-backed securities 1,448,917 1,461,286 1,301,083 1,311,373 Commercial mortgage-backed securities 615,730 618,848 817,570 812,886 Collateralized loan and debt obligations 369,126 371,256 419,795 405,128 Asset-backed securities 509,595 510,663 510,540 507,255 Total $ 6,674,309 $ 6,721,525 $ 6,392,829 $ 6,365,975
Fair Value of Trading Investments	The following table summarizes the fair value of the fixed maturity investments, short-term investments and equity securities classified as trading at December 31, 2016 and 2015 . December 31, 2016 December 31, 2015 Fixed maturity investments U.S. government and agencies securities $ 551,055 $ 319,674 U.S. state and municipal securities 6,006 5,559 Foreign government securities 110,088 49,861 Government guaranteed corporate securities 2,959 38,201 Corporate securities 1,051,200 532,192 Residential mortgage-backed securities 483,444 258,574 Commercial mortgage-backed securities 164,237 127,124 Collateralized loan and debt obligations 98,924 103,219 Asset-backed securities 272,142 152,756 Total fixed maturity investments 2,740,055 1,587,160 Short-term investments 330,199 394,111 Total fixed income investments $ 3,070,254 $ 1,981,271 Equity securities Equity investments $ 16,056 $ 14,676 Preferred equity investments — 553 Total equity securities $ 16,056 $ 15,229
Other Investments	The following table summarizes the composition and redemption restrictions of other investments as of December 31, 2016 and 2015 : December 31, 2016 Market Value Unfunded Commitments Ineligible for Redemption in 2017 Alternative funds Hedge funds $ 482,865 $ — $ 85,963 Private investment funds 76,451 92,214 76,451 Other investment funds 28,992 — 27,518 Total alternative funds 588,308 92,214 189,932 Total other investments $ 588,308 $ 92,214 $ 189,932 December 31, 2015 Market Value Unfunded Commitments Ineligible for Redemption in 2016 Alternative funds Hedge funds $ 704,966 $ — $ 57,876 Private investment funds 80,690 102,070 80,690 Other investment funds 23,465 — 24,958 Total alternative funds 809,121 102,070 163,524 Specialty funds High yield loan funds 63,496 — — Total specialty funds 63,496 — — Total other investments $ 872,617 $ 102,070 $ 163,524
Net Realized And Unrealized (Losses) Gains	The analysis of gross realized gains and losses, net unrealized gains and losses on trading securities, intangible asset impairment loss, and the change in the fair value of investment-related derivative financial instruments for the years ended December 31, 2016 , 2015 and 2014 are as follows: 2016 2015 2014 Gross realized gains on investment sales $ 39,033 $ 65,881 $ 35,921 Gross realized losses on investment sales (61,752 ) (28,636 ) (16,515 ) Net unrealized gains (losses) on trading securities 12,480 (24,257 ) — Intangible asset impairment loss (1) — — (5,450 ) Change in fair value of derivative financial instruments (2) (2,180 ) (328 ) 327 Net realized and unrealized (losses) gains $ (12,419 ) $ 12,660 $ 14,283 (1) For additional information on the Company's intangible assets, see Note 11, Goodwill and intangible assets. (2) For additional information on the Company's derivative financial instruments, see Note 9, Derivatives.
Amortized Cost, Fair Value, Unrealized Gains and Losses for Available for Sale Securities	December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturity investments U.S. government and agencies securities $ 499,386 $ 2,561 $ (3,153 ) $ 498,794 U.S. state and municipal securities 16,908 120 (181 ) 16,847 Foreign government securities 110,893 803 (581 ) 111,115 Government guaranteed corporate securities 19,248 311 (7 ) 19,552 Corporate securities 1,323,276 5,698 (11,232 ) 1,317,742 Residential mortgage-backed securities 1,041,540 16,400 (5,141 ) 1,052,799 Commercial mortgage-backed securities 689,078 4,737 (8,053 ) 685,762 Collateralized loan and debt obligations 304,915 796 (3,802 ) 301,909 Asset-backed securities 356,753 585 (2,839 ) 354,499 Total fixed maturity investments $ 4,361,997 $ 32,011 $ (34,989 ) $ 4,359,019 Short-term investments 25,657 28 — 25,685 Total fixed income investments $ 4,387,654 $ 32,039 $ (34,989 ) $ 4,384,704 Equity securities Equity investments $ 527,154 $ 6,835 $ (37,474 ) $ 496,515 Preferred equity investments 15,275 1,946 (151 ) 17,070 Total equity securities $ 542,429 $ 8,781 $ (37,625 ) $ 513,585 The amortized cost, fair value and related gross unrealized gains and losses on the Company's securities classified as available for sale at December 31, 2016 and 2015 are as follows: December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturity investments U.S. government and agencies securities $ 449,638 $ 3,981 $ (2,792 ) $ 450,827 U.S. state and municipal securities 11,560 945 (154 ) 12,351 Foreign government securities 68,539 2,236 (1,944 ) 68,831 Government guaranteed corporate securities 912 46 — 958 Corporate securities 1,078,756 26,481 (8,744 ) 1,096,493 Residential mortgage-backed securities 968,273 21,032 (11,463 ) 977,842 Commercial mortgage-backed securities 452,011 8,790 (6,190 ) 454,611 Collateralized loan and debt obligations 271,361 1,644 (673 ) 272,332 Asset-backed securities 237,177 2,242 (898 ) 238,521 Total fixed maturity investments $ 3,538,227 $ 67,397 $ (32,858 ) $ 3,572,766 Short-term investments 78,506 1 (2 ) 78,505 Total fixed income investments $ 3,616,733 $ 67,398 $ (32,860 ) $ 3,651,271 Equity securities Equity investments $ 461,509 $ 27,948 $ (4,545 ) $ 484,912 Preferred equity investments 175 — (2 ) 173 Total equity securities $ 461,684 $ 27,948 $ (4,547 ) $ 485,085
Available For Sale Securities In An Unrealized Loss Position	The following tables summarize, for all available for sale securities in an unrealized loss position at December 31, 2016 and 2015 , the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position. Less than 12 months 12 months or greater Total December 31, 2016 Unrealized Losses (1) Fair Value Unrealized Losses (1) Fair Value Unrealized Losses (1) Fair Value Fixed maturity investments U.S. government and agencies securities $ (2,791 ) $ 289,012 $ (1 ) $ 248 $ (2,792 ) $ 289,260 U.S. state and municipal securities (152 ) 5,288 (2 ) 2,143 (154 ) 7,431 Foreign government securities (446 ) 15,717 (1,498 ) 5,973 (1,944 ) 21,690 Corporate securities (7,512 ) 448,643 (1,232 ) 11,897 (8,744 ) 460,540 Residential mortgage-backed securities (10,082 ) 521,167 (1,381 ) 31,835 (11,463 ) 553,002 Commercial mortgage-backed securities (3,453 ) 174,144 (2,737 ) 76,694 (6,190 ) 250,838 Collateralized loan and debt obligations (223 ) 50,194 (450 ) 81,043 (673 ) 131,237 Asset-backed securities (539 ) 64,109 (359 ) 39,770 (898 ) 103,879 Total fixed maturity investments $ (25,198 ) $ 1,568,274 $ (7,660 ) $ 249,603 $ (32,858 ) $ 1,817,877 Short-term investments (2 ) 4,691 — — (2 ) 4,691 Total fixed income investments $ (25,200 ) $ 1,572,965 $ (7,660 ) $ 249,603 $ (32,860 ) $ 1,822,568 Equity securities Equity investments $ (2,855 ) $ 71,509 $ (1,690 ) $ 17,408 $ (4,545 ) $ 88,917 Preferred equity investments (2 ) 123 — — (2 ) 123 Total equity securities $ (2,857 ) $ 71,632 $ (1,690 ) $ 17,408 $ (4,547 ) $ 89,040 (1) Gross unrealized losses include unrealized losses on non-OTTI and non-credit OTTI securities recognized in accumulated other comprehensive loss at December 31, 2016 . Less than 12 months 12 months or greater Total December 31, 2015 Unrealized Losses (1) Fair Value Unrealized Losses (1) Fair Value Unrealized Losses (1) Fair Value Fixed maturity investments U.S. government and agencies securities $ (2,175 ) $ 347,024 $ (978 ) $ 16,669 $ (3,153 ) $ 363,693 U.S. state and municipal securities (96 ) 9,662 (85 ) 695 (181 ) 10,357 Foreign government securities (404 ) 31,881 (177 ) 3,966 (581 ) 35,847 Government guaranteed corporate securities (7 ) 1,692 — — (7 ) 1,692 Corporate securities (9,222 ) 830,349 (2,010 ) 51,024 (11,232 ) 881,373 Residential mortgage-backed securities (3,378 ) 365,082 (1,763 ) 79,355 (5,141 ) 444,437 Commercial mortgage-backed securities (6,708 ) 436,387 (1,345 ) 42,246 (8,053 ) 478,633 Collateralized loan and debt obligations (3,107 ) 224,520 (695 ) 48,167 (3,802 ) 272,687 Asset-backed securities (2,624 ) 311,814 (215 ) 12,880 (2,839 ) 324,694 Total fixed income investments $ (27,721 ) $ 2,558,411 $ (7,268 ) $ 255,002 $ (34,989 ) $ 2,813,413 Equity securities Equity investments $ (32,021 ) $ 329,280 $ (5,453 ) $ 56,421 $ (37,474 ) $ 385,701 Preferred equity investments (151 ) 7,361 — — (151 ) 7,361 Total equity securities $ (32,172 ) $ 336,641 $ (5,453 ) $ 56,421 $ (37,625 ) $ 393,062 (1) Gross unrealized losses include unrealized losses on non-OTTI and non-credit OTTI securities recognized in accumulated other comprehensive loss at December 31, 2015 .
Non-controlling Interests Rollforward	The following table summarizes the movements in the non-redeemable non-controlling interests balance for the year ended December 31, 2016 and from the acquisition date, July 31, 2015 to December 31, 2015 : Year Ended December 31, 2016 Five Months Ended December 31, 2015 Non-controlling interests, beginning balance $ 267,810 $ 258,529 Income attributable to third-party investments in the BCGR Cell 14,577 5,526 Income attributable to third-party investments in BCRH 9,553 5,490 Net income attributable to non-controlling interests 24,130 11,016 Net preferred share redemption attributable to third-party investments in the BCGR Cell (1) (19,799 ) — Net investments attributable to third-parties in BCRH 72 20 Net change in third-party investments in non-controlling interests (19,727 ) 20 Dividends declared by BCRH attributable to non-controlling interests (12,519 ) (1,755 ) Non-controlling interests - ending balance $ 259,694 $ 267,810 (1) The redemption from the BCGR Cell was required to fund expenses, repay debt and fund dividends by BCGR.

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Schedule Of Fixed Maturity Investments, Equity Securities, Short-term Investments, Derivative Instruments and Debt Measured On A Recurring Basis	The following table sets forth the Company's fixed maturity investments, equity securities, short-term investments, other assets and liabilities and debt categorized by the level within the hierarchy in which the fair value measurements fall at December 31, 2016 : Fair Value Measurements at December 31, 2016 Total at December 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Fixed maturity investments U.S. government and agencies securities $ 1,001,882 $ 51,827 $ 950,055 $ — U.S. state and municipal securities 18,357 — 18,357 — Foreign government securities 178,919 — 178,919 — Government guaranteed corporate securities 3,917 — 3,917 — Corporate securities 2,147,693 — 1,968,056 179,637 Residential mortgage-backed securities 1,461,286 — 1,461,286 — Commercial mortgage-backed securities 618,848 — 618,848 — Collateralized loan and debt obligations 371,256 — 371,256 — Asset-backed securities 510,663 — 510,663 — Total fixed maturity investments 6,312,821 51,827 6,081,357 179,637 Equity securities Equity investments 500,968 184,251 316,717 — Preferred equity investments 173 — 173 — Total equity securities 501,141 184,251 316,890 — Short-term investments 408,704 — 408,654 50 Other assets (see Note 9) 166,716 1,953 123,681 41,082 Total assets $ 7,389,382 $ 238,031 $ 6,930,582 $ 220,769 Liabilities Other liabilities (see Note 9) $ 84,069 $ 2,772 $ 55,051 $ 26,246 Debt 770,704 — 770,704 — Total liabilities $ 854,773 $ 2,772 $ 825,755 $ 26,246 The following table sets forth the Company's fixed maturity investments, equity securities, short-term investments, other assets and liabilities and debt categorized by the level within the hierarchy in which the fair value measurements fall at December 31, 2015 : Fair Value Measurements at December 31, 2015 Total at December 31, 2015 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Fixed maturity investments U.S. government and agencies securities $ 818,468 $ 37,741 $ 780,727 $ — U.S. state and municipal securities 22,406 — 22,406 — Foreign government securities 160,976 — 160,976 — Government guaranteed corporate securities 57,753 — 57,753 — Corporate securities 1,849,934 — 1,739,002 110,932 Residential mortgage-backed securities 1,311,373 — 1,311,373 — Commercial mortgage-backed securities 812,886 — 812,174 712 Collateralized loan and debt obligations 405,128 — 404,319 809 Asset-backed securities 507,255 — 507,255 — Total fixed maturity investments $ 5,946,179 $ 37,741 $ 5,795,985 $ 112,453 Equity securities Equity investments 511,191 275,086 236,105 — Preferred equity investments 17,623 — 17,623 — Total equity securities $ 528,814 $ 275,086 $ 253,728 $ — Short-term investments 419,796 — 419,796 — Other assets (see Note 9) 68,892 4 27,385 41,503 Total assets $ 6,963,681 $ 312,831 $ 6,496,894 $ 153,956 Liabilities Other liabilities (see Note 9) $ 46,088 $ — $ 4,059 $ 42,029 Debt 737,974 — 737,974 — Total liabilities $ 784,062 $ — $ 742,033 $ 42,029
Fair Value Inputs Assets And Liabilities Quantitative Information [Table Text Block]	Below is a summary of quantitative information regarding the significant observable and unobservable inputs used in determining the fair value of the net weather and energy related derivative assets and liabilities classified in Level 3 that are measured at fair value on a recurring basis at December 31, 2016 and 2015 : December 31, 2016 Fair Value (Level 3) Valuation Techniques Inputs Range Low High (Commodity curve in U.S. dollars in thousands) Net weather and energy related derivative assets $ 14,836 Historical Analysis and Simulation Correlation 0 1 Temperature -15F 115F Composite weather variable -25 deg. 45 deg. Rainfall 0" 2" Windspeed 0.01 m/s 25 m/s Wave height 0 m 25 m Commodity curve $ (1 ) $ 14 December 31, 2015 Fair Value (Level 3) Valuation Techniques Inputs Range Low High (Commodity curve in U.S. dollars in thousands) Net weather and energy related derivative liabilities $ 526 Historical Analysis and Simulation Correlation 0 1 Temperature -15F 115F Composite weather variable -25 deg. 45 deg. Rainfall 0" 2" Windspeed 0.01 m/s 25 m/s Snowfall 0" 18" Cyclone (category) — 5 Commodity curve $ — $ 13
Reconciliation Of The Beginning And Ending Balances For All Fixed Maturity Investments And Derivative Instruments Measured At Fair Value On A Recurring Basis Using Level 3 Inputs	The following tables present a reconciliation of the beginning and ending balances for all assets and liabilities measured at fair value on a recurring basis using Level 3 inputs during the years ended December 31, 2016 and 2015 . December 31, 2016 Fixed maturity investments Other assets Total assets Other liabilities Level 3, beginning of year $ 112,453 $ 41,503 $ 153,956 $ (42,029 ) Total equity income and losses and realized and unrealized gains and losses included in earnings 4,321 — 4,321 — Total income and losses included in other underwriting loss — 5,796 5,796 90 Change in unrealized gains and losses included in other comprehensive (loss) income 263 — 263 — Purchases 48,572 — 48,572 — Issues — 22,571 22,571 (34,219 ) Sales (57,987 ) — (57,987 ) — Settlements — (28,788 ) (28,788 ) 49,912 Transfers into Level 3 79,332 — 79,332 — Transfers out of Level 3 (7,267 ) — (7,267 ) — Level 3, end of year $ 179,687 $ 41,082 $ 220,769 $ (26,246 ) December 31, 2015 Fixed maturity investments Other assets Total assets Other liabilities Level 3, beginning of year $ 12,290 $ 25,615 $ 37,905 $ (35,366 ) Total equity income and losses and realized and unrealized gains and losses included in earnings (2,785 ) — (2,785 ) — Total income and losses included in other underwriting loss — (2,951 ) (2,951 ) 5,062 Change in unrealized gains and losses included in other comprehensive (loss) income (180 ) — (180 ) — Purchases 13 4,750 4,763 (4,231 ) Issues — 21,559 21,559 (34,114 ) Sales (15,695 ) — (15,695 ) — Settlements — (7,470 ) (7,470 ) 26,620 Transfers into Level 3 131,215 — 131,215 — Transfers out of Level 3 (12,405 ) — (12,405 ) — Level 3, end of year $ 112,453 $ 41,503 $ 153,956 $ (42,029 )

Reserve For Losses And Loss E46

Reserve For Losses And Loss Expenses (Tables)	12 Months Ended
	Dec. 31, 2016
Insurance Loss Reserves [Abstract]
Activity in the reserve for losses and loss expenses	Activity in the reserve for losses and loss expenses for the years ended December 31, 2016 , 2015 and 2014 is summarized as follows: 2016 2015 2014 Gross reserve for losses and loss expenses, January 1 $ 4,510,415 $ 3,846,859 $ 4,002,259 Reinsurance recoverable on unpaid losses 907,944 670,795 593,755 Net reserve for losses and loss expenses, January 1 3,602,471 3,176,064 3,408,504 Incurred related to: Current year 1,542,602 1,160,572 1,203,977 Prior years (221,550 ) (243,464 ) (233,815 ) Total incurred 1,321,052 917,108 970,162 Paid related to: Current year (295,863 ) (265,898 ) (439,169 ) Prior years (890,027 ) (867,739 ) (719,043 ) Total paid (1,185,890 ) (1,133,637 ) (1,158,212 ) Amounts acquired (1) — 675,019 — Foreign currency translation and other (45,624 ) (32,083 ) (44,390 ) Net reserve for losses and loss expenses, December 31 3,692,009 3,602,471 3,176,064 Reinsurance recoverable on unpaid losses 1,213,129 907,944 670,795 Gross reserve for losses and loss expenses, December 31 $ 4,905,138 $ 4,510,415 $ 3,846,859 (1) Represents the fair value of Montpelier's reserve for losses and loss expenses and reinsurance recoverable acquired at July 31, 2015.
Claims development tables	The following tables show, by segment by line of business, the incurred losses and loss expenses and cumulative paid losses and loss expenses, net of reinsurance, as of December 31, 2016 . The following also includes the amount of IBNR reserves recorded as well as the cumulative number of reported claims for the Insurance segment lines of business and only excess of loss reinsurance contracts for the Reinsurance segment lines of business. Insurance Segment - Agriculture Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ — $ — $ — $ — $ — $ — $ — $ — $ — $ — $ — — 2008 — 333,380 318,709 313,296 313,800 313,814 313,938 313,834 313,834 313,834 — 30,036 2009 — — 298,914 284,277 280,798 281,667 281,594 281,365 281,365 281,365 — 26,540 2010 — — — 305,131 280,330 280,409 280,166 280,008 280,008 280,008 — 18,331 2011 — — — — 520,388 509,531 508,424 507,930 507,847 507,847 — 37,061 2012 — — — — — 581,455 576,836 573,376 572,995 572,469 — 38,297 2013 — — — — — — 566,483 563,158 562,122 562,826 — 44,138 2014 — — — — — — — 451,710 451,843 449,705 — 53,886 2015 — — — — — — — — 241,501 227,634 — 39,508 2016 — — — — — — — — — 200,353 20,453 29,353 Total $ 3,396,041 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ — $ — $ — $ — $ — $ — $ — $ — $ — $ — 2008 — 239,498 310,235 313,196 313,708 313,722 313,859 313,834 313,834 313,834 2009 — — 178,206 281,996 280,468 280,991 281,058 281,365 281,365 281,365 2010 — — — 144,296 279,397 279,768 279,859 280,008 280,008 280,008 2011 — — — — 461,335 506,905 507,790 507,918 507,847 507,847 2012 — — — — — 478,797 573,781 572,885 572,995 572,469 2013 — — — — — — 438,034 562,046 562,075 561,652 2014 — — — — — — — 352,202 448,046 449,705 2015 — — — — — — — — 122,696 222,212 2016 — — — — — — — — — 75,894 Total $ 3,264,986 Reserve for losses and loss expenses, net of reinsurance $ 131,055 6. Reserve for losses and loss expenses, cont'd. Insurance Segment - Casualty & Other Specialty Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 254,678 $ 251,840 $ 228,021 $ 232,156 $ 232,186 $ 235,482 $ 213,895 $ 197,246 $ 196,072 $ 191,927 $ 20,274 988 2008 — 285,334 296,079 333,844 366,479 363,094 347,477 339,927 328,153 312,759 35,706 1,602 2009 — — 198,689 240,235 237,368 237,101 234,983 230,594 218,900 206,077 24,553 2,509 2010 — — — 150,636 179,854 179,208 175,922 160,450 135,214 122,748 19,995 2,738 2011 — — — — 151,344 169,803 222,470 226,274 201,355 186,588 48,836 4,319 2012 — — — — — 164,568 182,924 187,141 183,644 179,929 73,724 6,268 2013 — — — — — — 153,377 165,853 205,041 230,081 81,540 6,790 2014 — — — — — — — 120,226 132,184 141,970 84,031 7,969 2015 — — — — — — — — 145,828 156,771 77,472 8,717 2016 — — — — — — — — — 165,558 137,608 5,305 Total $ 1,894,408 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 9,090 $ 38,777 $ 66,865 $ 103,283 $ 124,887 $ 139,923 $ 144,982 $ 152,297 $ 159,687 $ 163,236 2008 — 36,479 82,811 129,840 169,331 200,021 239,185 255,585 261,201 266,264 2009 — — 15,098 50,815 83,210 103,922 139,011 150,241 160,903 168,351 2010 — — — 863 4,279 27,379 64,917 83,634 88,737 96,785 2011 — — — — 3,279 14,468 30,074 54,598 91,817 97,285 2012 — — — — — 3,707 16,190 32,686 51,381 75,508 2013 — — — — — — 3,145 15,581 89,771 119,524 2014 — — — — — — — 3,389 18,914 36,446 2015 — — — — — — — — 18,426 49,196 2016 — — — — — — — — — 14,281 Total $ 1,086,876 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 30,599 Adjustment for unallocated claim expenses 43,666 Reserve for losses and loss expenses, net of reinsurance $ 881,797 6. Reserve for losses and loss expenses, cont'd. Insurance Segment - Professional Lines Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 52,739 $ 110,525 $ 150,972 $ 120,358 $ 119,243 $ 117,895 $ 113,520 $ 116,711 $ 125,496 $ 122,969 $ 47 232 2008 — 62,838 62,586 83,358 88,047 96,887 109,471 127,641 138,119 164,412 3,932 379 2009 — — 100,914 118,432 104,421 106,597 109,441 99,973 92,165 93,803 5,728 1,039 2010 — — — 108,369 105,611 101,591 92,931 82,421 74,856 69,387 9,860 1,594 2011 — — — — 102,012 98,353 99,466 79,988 98,989 105,619 15,265 1,232 2012 — — — — — 101,872 103,358 101,426 79,591 69,333 18,080 1,233 2013 — — — — — — 78,988 79,732 70,564 61,499 27,377 1,255 2014 — — — — — — — 64,437 66,524 57,446 29,232 2,599 2015 — — — — — — — — 74,823 72,559 58,966 3,464 2016 — — — — — — — — — 107,761 99,005 3,814 Total $ 924,788 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 83 $ 987 $ 1,744 $ 62,321 $ 90,128 $ 100,560 $ 100,693 $ 110,254 $ 120,328 $ 122,867 2008 — 54 1,898 14,027 15,888 16,613 48,997 72,576 98,770 113,175 2009 — — 1,045 8,755 32,193 38,000 56,126 73,072 77,628 80,201 2010 — — — 1,932 16,014 27,557 36,506 46,982 48,978 51,885 2011 — — — — 2,367 11,766 21,266 33,639 71,782 85,003 2012 — — — — — 2,582 13,185 22,237 29,854 35,678 2013 — — — — — — 2,193 13,807 21,289 26,783 2014 — — — — — — — 1,167 7,081 20,020 2015 — — — — — — — — 1,243 7,130 2016 — — — — — — — — — 2,324 Total $ 545,066 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 61 Adjustment for unallocated claim expenses 26,477 Reserve for losses and loss expenses, net of reinsurance $ 406,260 6. Reserve for losses and loss expenses, cont'd. Insurance Segment - Property, Marine/Energy & Aviation Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 45,128 $ 32,772 $ 25,714 $ 28,766 $ 29,071 $ 28,925 $ 33,206 $ 33,741 $ 34,083 $ 32,680 $ — 201 2008 — 113,427 104,626 84,425 74,111 84,093 80,158 78,176 78,178 77,373 13 459 2009 — — 60,589 48,196 23,651 21,225 19,933 19,423 19,780 19,341 33 568 2010 — — — 93,741 54,986 48,033 42,918 41,703 42,202 43,240 992 1,423 2011 — — — — 163,234 139,932 125,588 124,243 127,840 133,297 256 2,486 2012 — — — — — 172,535 137,329 123,134 121,281 121,873 405 2,704 2013 — — — — — — 115,600 101,878 85,794 80,971 3,933 3,145 2014 — — — — — — — 136,748 114,243 102,002 7,588 4,405 2015 — — — — — — — — 183,192 184,867 18,890 6,281 2016 — — — — — — — — — 234,235 72,271 6,600 Total $ 1,029,879 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 10,626 $ 19,644 $ 21,987 $ 22,614 $ 23,482 $ 23,780 $ 32,561 $ 33,546 $ 34,084 $ 32,671 2008 — 40,140 57,685 62,922 64,434 75,187 75,042 77,234 77,910 77,239 2009 — — 11,014 16,967 18,120 18,657 18,887 19,075 19,407 19,261 2010 — — — 11,680 29,150 33,938 36,306 38,880 40,782 41,802 2011 — — — — 17,871 63,710 82,967 103,301 117,337 123,496 2012 — — — — — 18,709 79,533 87,216 102,447 108,983 2013 — — — — — — 20,929 57,243 66,851 71,423 2014 — — — — — — — 26,491 60,418 79,321 2015 — — — — — — — — 52,121 131,697 2016 — — — — — — — — — 77,448 Total $ 763,341 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 3 Adjustment for unallocated claim expenses 7,855 Reserve for losses and loss expenses, net of reinsurance $ 274,396 6. Reserve for losses and loss expenses, cont'd. Reinsurance Segment - Catastrophe Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 168,640 $ 126,561 $ 104,527 $ 102,855 $ 91,502 $ 88,252 $ 86,273 $ 90,379 $ 97,851 $ 102,929 $ 153 192 2008 — 405,190 378,838 389,111 392,668 384,117 382,382 382,068 384,864 381,551 317 336 2009 — — 102,411 74,817 59,051 55,933 55,229 56,944 58,910 60,788 559 204 2010 — — — 272,094 234,576 226,060 226,208 231,531 237,677 224,323 1,394 265 2011 — — — — 622,350 591,965 589,614 603,680 612,274 624,448 4,640 574 2012 — — — — — 245,011 180,145 163,109 154,240 151,003 3,884 345 2013 — — — — — — 157,097 129,469 127,984 124,311 1,454 315 2014 — — — — — — — 141,173 126,822 126,512 3,156 229 2015 — — — — — — — — 60,465 47,255 4,057 224 2016 — — — — — — — — — 137,357 27,654 216 Total $ 1,980,477 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 31,590 $ 85,271 $ 87,267 $ 91,214 $ 83,511 $ 82,285 $ 80,852 $ 88,684 $ 97,279 $ 102,497 2008 — 154,382 255,721 316,023 353,658 375,455 378,322 380,366 382,431 380,409 2009 — — 26,869 45,763 48,440 49,847 51,013 54,189 57,551 59,865 2010 — — — 58,556 124,322 152,264 173,341 193,340 207,716 208,329 2011 — — — — 230,619 385,304 495,351 561,864 593,831 615,504 2012 — — — — — 56,614 105,745 126,802 134,288 136,862 2013 — — — — — — 34,236 83,259 106,983 116,996 2014 — — — — — — — 49,337 107,546 117,040 2015 — — — — — — — — 20,084 31,850 2016 — — — — — — — — — 43,793 Total $ 1,813,145 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 91 Adjustment for unallocated claim expenses 3,002 Reserve for losses and loss expenses, net of reinsurance $ 170,425 6. Reserve for losses and loss expenses, cont'd. Reinsurance Segment - Property Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 123,502 $ 137,474 $ 127,294 $ 120,598 $ 116,552 $ 115,947 $ 119,773 $ 121,653 $ 121,902 $ 117,706 $ 2 309 2008 — 173,437 151,764 133,022 123,162 124,861 126,887 126,991 125,622 122,943 3 612 2009 — — 151,371 123,151 116,114 114,137 114,342 115,111 115,213 111,782 114 991 2010 — — — 221,480 216,726 190,322 186,817 188,516 188,304 174,952 419 1,126 2011 — — — — 344,015 334,865 312,365 312,278 305,567 335,228 2,089 942 2012 — — — — — 314,924 259,753 240,928 240,070 244,651 2,224 813 2013 — — — — — — 255,632 239,844 217,661 199,195 5,650 1,017 2014 — — — — — — — 211,769 211,888 197,761 11,702 1,060 2015 — — — — — — — — 184,586 181,761 16,927 880 2016 — — — — — — — — — 166,629 55,289 542 Total $ 1,852,608 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 23,678 $ 71,828 $ 103,059 $ 111,825 $ 111,155 $ 112,559 $ 116,499 $ 119,203 $ 120,881 $ 116,680 2008 — 30,553 79,457 104,279 107,291 110,039 118,745 122,512 123,954 121,472 2009 — — 27,690 71,123 89,940 97,377 103,688 107,021 109,796 107,609 2010 — — — 49,442 117,260 141,348 163,173 175,919 180,555 170,367 2011 — — — — 76,880 172,679 254,657 286,065 291,961 326,570 2012 — — — — — 53,488 146,671 192,022 214,711 230,684 2013 — — — — — — 55,668 138,841 173,888 176,721 2014 — — — — — — — 51,635 134,663 158,766 2015 — — — — — — — — 37,685 100,328 2016 — — — — — — — — — 33,787 Total $ 1,542,984 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 4,954 Adjustment for unallocated claim expenses 4,301 Reserve for losses and loss expenses, net of reinsurance $ 318,879 6. Reserve for losses and loss expenses, cont'd. Reinsurance Segment - Casualty Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 108,468 $ 116,074 $ 116,095 $ 120,815 $ 115,024 $ 114,484 $ 112,945 $ 111,664 $ 110,369 $ 112,366 $ 13,382 549 2008 — 112,680 118,736 116,204 114,790 107,336 101,613 98,504 97,260 93,732 9,538 406 2009 — — 116,515 126,969 124,218 127,972 126,505 121,969 115,317 114,901 20,438 433 2010 — — — 186,667 179,891 176,073 170,938 172,699 160,142 159,409 27,794 506 2011 — — — — 198,159 199,035 197,138 204,187 195,094 196,946 35,929 604 2012 — — — — — 195,983 191,436 193,164 183,512 174,625 42,134 701 2013 — — — — — — 178,401 172,604 170,144 163,986 62,188 842 2014 — — — — — — — 125,515 120,521 119,143 45,271 615 2015 — — — — — — — — 119,276 119,529 58,182 250 2016 — — — — — — — — — 143,263 106,858 127 Total $ 1,397,900 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 3,009 $ 13,399 $ 23,890 $ 35,928 $ 48,519 $ 57,254 $ 64,711 $ 73,518 $ 77,378 $ 87,170 2008 — 8,475 17,338 30,528 43,923 51,831 58,419 67,856 72,592 75,906 2009 — — 7,367 21,841 34,770 51,576 61,615 70,558 76,463 83,892 2010 — — — 14,826 34,469 56,997 75,290 92,382 104,037 114,875 2011 — — — — 28,035 50,998 77,748 104,394 116,519 141,449 2012 — — — — — 30,667 54,457 75,456 92,072 105,209 2013 — — — — — — 18,577 35,808 56,564 71,677 2014 — — — — — — — 10,390 33,215 49,951 2015 — — — — — — — — 15,817 34,396 2016 — — — — — — — — — 18,837 Total $ 783,362 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 106,483 Adjustment for unallocated claim expenses 10,637 Reserve for losses and loss expenses, net of reinsurance $ 731,658 6. Reserve for losses and loss expenses, cont'd. Reinsurance Segment - Professional Lines Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 46,031 $ 51,283 $ 49,539 $ 43,988 $ 41,956 $ 41,037 $ 43,261 $ 42,115 $ 41,989 $ 37,980 $ 1,539 310 2008 — 41,797 50,276 47,154 44,672 47,084 44,526 42,863 41,599 39,059 1,171 262 2009 — — 41,430 43,003 41,681 40,763 35,771 36,560 36,474 38,720 2,098 204 2010 — — — 58,153 58,567 67,335 62,185 53,825 46,661 45,024 3,733 110 2011 — — — — 55,812 56,535 55,286 44,921 36,691 31,390 4,828 57 2012 — — — — — 43,519 42,443 43,426 36,707 30,576 5,803 81 2013 — — — — — — 48,933 49,513 45,382 41,403 21,619 48 2014 — — — — — — — 91,943 88,915 90,713 50,367 62 2015 — — — — — — — — 130,595 130,832 99,261 55 2016 — — — — — — — — — 148,671 139,857 10 Total $ 634,368 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 144 $ 2,310 $ 5,649 $ 10,694 $ 16,764 $ 21,259 $ 28,121 $ 30,796 $ 33,144 $ 32,771 2008 — 341 2,156 6,200 12,752 22,496 26,811 30,169 32,873 33,434 2009 — — 1,033 3,330 7,963 15,666 19,184 23,469 27,039 32,329 2010 — — — 2,249 7,348 14,481 24,511 31,313 36,100 36,181 2011 — — — — 1,685 4,943 9,405 15,168 20,124 22,142 2012 — — — — — 965 1,929 4,204 9,147 13,757 2013 — — — — — — 997 2,561 6,694 11,636 2014 — — — — — — — 1,149 6,446 22,822 2015 — — — — — — — — 2,941 14,357 2016 — — — — — — — — — 1,920 Total $ 221,349 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 5,540 Adjustment for unallocated claim expenses 6,164 Reserve for losses and loss expenses, net of reinsurance $ 424,723 6. Reserve for losses and loss expenses, cont'd. Reinsurance Segment - Specialty Incurred losses and loss expenses, net of reinsurance For the years ended December 31, At December 31, 2016 Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 IBNR reserves Cumulative number of reported claims (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 229,505 $ 202,655 $ 197,905 $ 193,084 $ 189,577 $ 187,961 $ 187,949 $ 185,743 $ 183,044 $ 174,205 $ 435 288 2008 — 125,389 94,050 92,039 79,903 79,052 77,556 75,348 73,745 67,604 3,549 195 2009 — — 98,431 81,269 73,387 69,691 67,605 65,333 62,834 62,501 4,414 170 2010 — — — 123,741 107,630 97,718 86,949 85,252 84,817 82,937 1,856 218 2011 — — — — 111,517 100,639 86,832 82,514 82,984 82,014 2,565 274 2012 — — — — — 135,448 111,813 99,700 92,162 85,852 5,174 294 2013 — — — — — — 103,014 93,335 92,119 83,806 9,865 329 2014 — — — — — — — 120,335 116,642 108,392 19,693 342 2015 — — — — — — — — 150,288 149,473 35,118 318 2016 — — — — — — — — — 156,042 111,660 134 Total $ 1,052,826 Cumulative paid losses and loss expenses, net of reinsurance For the years ended December 31, Accident Year 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2007 $ 16,023 $ 123,632 $ 143,800 $ 153,622 $ 160,113 $ 169,797 $ 174,059 $ 175,948 $ 177,082 $ 169,673 2008 — 15,525 38,261 47,410 52,461 58,971 61,915 64,489 65,005 61,384 2009 — — 13,286 33,142 39,439 43,804 47,556 52,481 52,635 55,068 2010 — — — 15,110 48,043 57,822 64,199 68,915 72,072 74,797 2011 — — — — 22,755 44,494 61,019 68,869 73,730 75,760 2012 — — — — — 29,756 53,695 64,242 72,510 74,517 2013 — — — — — — 14,696 37,621 52,015 62,458 2014 — — — — — — — 23,579 49,847 66,813 2015 — — — — — — — — 18,994 70,659 2016 — — — — — — — — — 19,265 Total $ 730,394 Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance 24,265 Adjustment for unallocated claim expenses 6,119 Reserve for losses and loss expenses, net of reinsurance $ 352,816
Reconciliation of claims development to liability	The following is a reconciliation of the net incurred and paid claims development tables to the reserve for losses and loss expenses in the consolidated balance sheet at December 31, 2016 . December 31, 2016 Net reserve for losses and loss expenses Reinsurance recoverable on unpaid losses Gross reserve for losses and loss expenses Insurance Agriculture $ 131,055 $ 116,832 $ 247,887 Casualty & other specialty 881,797 490,447 1,372,244 Professional lines 406,260 305,114 711,374 Property, marine/energy & aviation 274,396 193,088 467,484 Reinsurance Catastrophe 170,425 39,419 209,844 Property 318,879 1,466 320,345 Casualty 731,658 1,175 732,833 Professional lines 424,723 449 425,172 Specialty 352,816 65,139 417,955 Total $ 3,692,009 $ 1,213,129 $ 4,905,138
Claims duration	The following is unaudited supplementary information about historical average claims duration by line of business. Average annual percentage payout of incurred claims by age, net of reinsurance (number of years) 1 2 3 4 5 6 7 8 9 10 Insurance Segment Agriculture 73.3 % 24.1 % 0.1 % 0.3 % — % — % — % — % — % — % Casualty & other specialty 5.5 % 11.3 % 15.5 % 15.1 % 12.8 % 7.1 % 4.5 % 2.7 % 3.7 % 1.4 % Professional lines 1.5 % 7.8 % 11.0 % 14.3 % 15.0 % 14.4 % 10.3 % 8.9 % 8.3 % 7.2 % Property, marine/energy & aviation 24.4 % 39.3 % 18.0 % 9.9 % 4.3 % 2.1 % 3.2 % 0.4 % 1.1 % 0.2 % Reinsurance Segment Catastrophe 32.4 % 36.1 % 15.4 % 7.6 % 3.4 % 1.7 % 0.2 % 0.3 % 1.3 % 1.0 % Property 24.1 % 39.4 % 19.5 % 6.5 % 3.5 % 2.7 % 0.5 % 0.9 % 0.9 % 0.3 % Casualty 9.2 % 12.6 % 12.7 % 11.9 % 9.9 % 8.2 % 6.3 % 5.5 % 4.4 % 3.2 % Professional lines 1.9 % 6.7 % 12.1 % 18.5 % 16.9 % 12.2 % 8.2 % 6.4 % 4.3 % 3.3 % Specialty 13.9 % 37.7 % 20.6 % 7.0 % 7.6 % 4.6 % 2.2 % 3.1 % 0.6 % — %

Reinsurance (Tables)

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2016
Reinsurance Disclosures [Abstract]
Effects Of Reinsurance On Premiums Written And Earned	The effects of reinsurance on premiums earned and written during the years ended December 31, 2016 , 2015 and 2014 are as follows: Year Ended December 31, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Earned Written Earned Written Earned Written Direct $ 2,336,314 $ 2,570,494 $ 1,938,830 $ 2,085,901 $ 1,521,648 $ 1,716,128 Assumed 1,635,379 1,631,676 1,331,831 1,234,960 1,132,370 1,177,948 Ceded (1,608,033 ) (1,832,235 ) (1,292,208 ) (1,370,391 ) (790,040 ) (959,870 ) $ 2,363,660 $ 2,369,935 $ 1,978,453 $ 1,950,470 $ 1,863,978 $ 1,934,206
Losses Recoverable By Rating	The balance of reinsurance recoverable on paid and unpaid losses at December 31, 2016 and 2015 was distributed as follows based on the ratings of the reinsurers: Rating December 31, 2016 December 31, 2015 U.S. Government sponsored program $ 141,443 $ 234,596 A+ and above 889,814 458,255 A 397,691 476,184 A- 5,805 7,060 Not rated 52,165 19,875 Total $ 1,486,918 $ 1,195,970

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule Of The Fair Values And The Related Notional Values Of Derivatives Included In The Company's Consolidated Balance Sheet	The fair values and the related notional values of derivatives at December 31, 2016 and 2015 are noted below. December 31, 2016 December 31, 2015 Fair Value Notional Principal Amount Fair Value Notional Principal Amount Derivatives recorded in other assets Foreign exchange forward contracts $ 629 $ 34,630 $ 425 $ 38,818 Credit default swaps 266 5,450 36 4,225 Interest rate swaps 374 7,000 — — ILWs 1,010 20,000 — — TBAs 121,402 120,300 26,924 25,700 Energy and weather contracts 43,035 101,436 41,507 70,388 Total recorded in other assets $ 166,716 $ 68,892 Derivatives recorded in other liabilities Foreign exchange forward contracts $ 1,204 $ 32,080 $ 372 $ 30,400 Credit default swaps 21 2,744 276 7,800 Interest rate swaps 59 1,100 7 42,000 Interest rate swaptions 34 5,400 — — Interest rate futures — — 8 54,488 ILWs 184 14,209 259 19,500 LIBOR swap 27 100,000 233 100,000 TBAs 50,704 50,400 — — Loss development cover 2,818 24,451 2,904 22,322 Energy and weather contracts 29,018 162,900 42,029 148,325 Total recorded in other liabilities $ 84,069 $ 46,088 Net derivative asset $ 82,647 $ 22,804
Schedule Of The Gains And Losses On The Consolidated Statements Of Income And Comprehensive Income From Derivatives	The gains and losses on the Consolidated Statements of Income and Comprehensive Income for derivatives for the years ended December 31, 2016 , 2015 and 2014 were as follows: 2016 2015 2014 Total gain included in net foreign exchange (gains) losses from foreign exchange forward contracts $ 516 $ 2,095 $ 1,880 Interest rate futures (160 ) 79 121 Credit default swaps 7 (50 ) 30 Interest rate swaps 124 (915 ) (4,239 ) Interest rate swaptions (20 ) 56 477 ILWs (1,675 ) (326 ) — LIBOR swap 206 332 — TBAs (662 ) 496 3,938 Total (losses) gains included in net realized and unrealized (losses) gains (2,180 ) (328 ) 327 Energy and weather contracts 4,835 2,281 (315 ) Loss development cover (2,129 ) (1,419 ) — Total gain (loss) included in other underwriting loss 2,706 862 (315 ) Total gains from derivatives $ 1,042 $ 2,629 $ 1,892

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Summary Of The Segment Revenues, Results And Reserve For Losses And Loss Expenses And The Carrying Value Of Goodwill	The following table provides a summary of the segment revenues and results for the year ended December 31, 2014 , reserve for losses and loss expenses as of December 31, 2014 and the carrying value of goodwill as of December 31, 2014 : Insurance Reinsurance Total Revenues Gross premiums written $ 1,716,128 $ 1,177,948 $ 2,894,076 Ceded premiums written (855,722 ) (104,148 ) (959,870 ) Net premiums written 860,406 1,073,800 1,934,206 Net premiums earned 833,912 1,030,066 1,863,978 Other underwriting loss — (5,786 ) (5,786 ) 833,912 1,024,280 1,858,192 Expenses Net losses and loss expenses 594,561 375,601 970,162 Acquisition expenses 65,368 254,145 319,513 General and administrative expenses 148,475 98,912 247,387 808,404 728,658 1,537,062 Underwriting income $ 25,508 $ 295,622 321,130 Net investment income 131,543 Corporate expenses (66,200 ) Net foreign exchange losses (3,839 ) Net realized and unrealized gains 14,283 Net impairment losses recognized in earnings (625 ) Amortization of intangibles (6,484 ) Interest expense (40,968 ) Income before income taxes $ 348,840 Net loss ratio 71.4 % 36.4 % 52.1 % Acquisition expense ratio 7.8 % 24.7 % 17.1 % General and administrative expense ratio 17.7 % 9.6 % 16.8 % (1) Combined ratio 96.9 % 70.7 % 86.0 % Reserve for losses and loss expenses $ 2,123,772 $ 1,723,087 $ 3,846,859 Goodwill $ 47,925 $ 43,313 $ 91,238 (1) Total general and administrative expense ratio includes general and administrative expenses and corporate expenses. The following table provides a summary of the segment revenues and results for the year ended December 31, 2016 , reserve for losses and loss expenses as of December 31, 2016 and the carrying value of goodwill as of December 31, 2016 : Insurance Reinsurance Total Revenues Gross premiums written $ 2,570,494 $ 1,631,676 $ 4,202,170 Ceded premiums written (1,514,240 ) (317,995 ) (1,832,235 ) Net premiums written 1,056,254 1,313,681 2,369,935 Net premiums earned 1,009,375 1,354,285 2,363,660 Other underwriting loss — (909 ) (909 ) 1,009,375 1,353,376 2,362,751 Expenses Net losses and loss expenses 684,178 636,874 1,321,052 Acquisition expenses 149,763 310,720 460,483 General and administrative expenses 140,742 107,404 248,146 974,683 1,054,998 2,029,681 Underwriting income $ 34,692 $ 298,378 333,070 Net investment income 176,590 Corporate expenses (51,706 ) Net foreign exchange gains 74,684 Net realized and unrealized losses (12,419 ) Net impairment losses recognized in earnings (10,769 ) Amortization of intangibles (84,624 ) Interest expense (43,860 ) Income before income taxes $ 380,966 Net loss ratio 67.9 % 47.1 % 55.9 % Acquisition expense ratio 14.8 % 22.9 % 19.5 % General and administrative expense ratio 13.9 % 7.9 % 12.7 % (1) Combined ratio 96.6 % 77.9 % 88.1 % Reserve for losses and loss expenses $ 2,798,989 $ 2,106,149 $ 4,905,138 Goodwill $ 83,550 $ 91,932 $ 175,482 (1) Total general and administrative expense ratio includes general and administrative expenses and corporate expenses. The following table provides a summary of the segment revenues and results for the year ended December 31, 2015 , reserve for losses and loss expenses as of December 31, 2015 and the carrying value of goodwill as of December 31, 2015 : Insurance Reinsurance Total Revenues Gross premiums written $ 2,085,901 $ 1,234,960 $ 3,320,861 Ceded premiums written (1,205,528 ) (164,863 ) (1,370,391 ) Net premiums written 880,373 1,070,097 1,950,470 Net premiums earned 824,552 1,153,901 1,978,453 Other underwriting loss — (3,694 ) (3,694 ) 824,552 1,150,207 1,974,759 Expenses Net losses and loss expenses 500,867 416,241 917,108 Acquisition expenses 80,252 267,633 347,885 General and administrative expenses 140,012 119,779 259,791 721,131 803,653 1,524,784 Underwriting income $ 103,421 $ 346,554 449,975 Net investment income 113,826 Corporate expenses (114,429 ) Net foreign exchange losses (26,964 ) Net realized and unrealized gains 12,660 Net impairment losses recognized in earnings (3,715 ) Amortization of intangibles (30,620 ) Interest expense (41,260 ) Income before income taxes $ 359,473 Net loss ratio 60.8 % 36.0 % 46.4 % Acquisition expense ratio 9.7 % 23.2 % 17.6 % General and administrative expense ratio 17.0 % 10.4 % 18.9 % (1) Combined ratio 87.5 % 69.6 % 82.9 % Reserve for losses and loss expenses $ 2,493,894 $ 2,016,521 $ 4,510,415 Goodwill $ 84,525 $ 91,930 $ 176,455 (1) Total general and administrative expense ratio includes general and administrative expenses and corporate expenses.
Schedule Of Gross Premiums Written By Line Of Business	The following table provides gross premiums written by line of business for the years ended December 31, 2016 , 2015 and 2014 : Business Segment 2016 2015 2014 Insurance Agriculture $ 760,877 $ 840,445 $ 866,025 Casualty and other specialty 657,558 514,203 396,113 Professional lines 461,552 344,482 263,538 Property, marine/energy and aviation 690,507 386,771 190,452 Total Insurance 2,570,494 2,085,901 1,716,128 Reinsurance Catastrophe 506,300 311,914 343,213 Property 250,447 209,392 287,326 Casualty 245,092 176,506 159,533 Professional lines 256,337 248,610 174,656 Specialty 373,500 288,538 213,220 Total Reinsurance 1,631,676 1,234,960 1,177,948 Total $ 4,202,170 $ 3,320,861 $ 2,894,076
Schedule Of Geographic Distribution Of Gross Premiums Written	The following table provides the geographic distribution of gross premiums written for the years ended December 31, 2016 , 2015 and 2014 : 2016 2015 2014 United States $ 2,823,950 $ 2,305,301 $ 2,054,431 Worldwide 794,289 566,664 456,078 Europe 265,100 209,729 172,077 Asia 105,838 75,165 38,442 Japan 82,864 58,524 45,618 Australasia 49,727 41,309 61,994 Other 80,402 64,169 65,436 Total $ 4,202,170 $ 3,320,861 $ 2,894,076

Goodwill And Intangible Asset50

Goodwill And Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule Of Goodwill And Intangible Assets	The following table shows an analysis of goodwill and intangible assets for the years ended December 31, 2016 and 2015 : Goodwill Intangible assets with indefinite lives Intangible assets with finite lives Total Net balance at December 31, 2014 $ 91,238 $ 11,779 $ 50,388 $ 153,405 Additions (1) 87,367 57,600 293,218 438,185 Amortization — — (30,620 ) (30,620 ) Foreign currency translation (2,150 ) (2,738 ) (2,122 ) (7,010 ) Net balance at December 31, 2015 $ 176,455 $ 66,641 $ 310,864 $ 553,960 Additions (973 ) — 11 (962 ) Amortization — — (84,624 ) (84,624 ) Net balance at December 31, 2016 $ 175,482 $ 66,641 $ 226,251 $ 468,374 Gross balance $ 177,632 $ 74,829 $ 431,271 $ 683,732 Accumulated amortization — — (202,898 ) (202,898 ) Accumulated impairment losses — (5,450 ) — (5,450 ) Accumulated foreign currency translation (2,150 ) (2,738 ) (2,122 ) (7,010 ) Net balance $ 175,482 $ 66,641 $ 226,251 $ 468,374 (1) For additional information on the intangible assets acquired during 2015, see Note 3, Acquisition of Montpelier.

Commitments And Contingencies (

Commitments And Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Schedule Of Percentage Of Gross Premiums Written Generated Through Company's Largest Brokers	The following table shows the percentage of gross premiums written generated through the Company's largest brokers for the years ended December 31, 2016 , 2015 and 2014 : Broker 2016 2015 2014 Marsh & McLennan Companies, Inc. 20.9 % 19.8 % 19.1 % Aon Benfield 14.3 % 12.8 % 13.2 % Willis Companies 8.9 % 9.2 % 10.6 % Total of largest brokers 44.1 % 41.8 % 42.9 %
Schedule Of Future Minimum Lease Commitments	Future minimum lease commitments at December 31, 2016 are as follows: Year ending December 31, Amount 2017 $ 15,895 2018 19,945 2019 22,420 2020 21,060 2021 19,099 2022 and thereafter 103,443 $ 201,862

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Schedule Of Company's Share Capital	The Company’s share capital at December 31, 2016 and 2015 is comprised as follows: 2016 2015 Preferred shares Authorized – $1.00 par value each 9,200 9,209,200 Issued, outstanding and fully paid: Series B preferred shares - $1.00 par value each; aggregate liquidation preference nil (2015 - $230,000) — 9,200,000 Series C preferred shares – $1.00 par value each; aggregate liquidation preference $230,000 (2015 - $230,000) 9,200 9,200 9,200 9,209,200 Common shares Authorized - $1.00 par value each 120,000,000 120,000,000 Issued, outstanding and fully paid: Ordinary common shares - $1.00 par value each 67,627,901 66,797,991
Schedule Of Accumulated Other Comprehensive (Loss) Income	The following table presents the changes in accumulated other comprehensive (loss) income balances by component for the years ended December 31, 2016 and 2015 : For the Year Ended December 31, 2016 Losses on cash flow hedges Unrealized (losses) gains on available for sale securities Foreign currency translation adjustments Total Beginning balance $ (1,678 ) $ (12,638 ) $ (32,318 ) $ (46,634 ) Other comprehensive (loss) income before reclassifications — 54,287 (86,324 ) (32,037 ) Amounts reclassified from accumulated other comprehensive loss (1) 88 19,834 — 19,922 Net current period other comprehensive loss 88 74,121 (86,324 ) (12,115 ) Ending balance $ (1,590 ) $ 61,483 $ (118,642 ) $ (58,749 ) (1) All amounts are net of tax. For the Year Ended December 31, 2015 Losses on cash flow hedges Unrealized (losses) gains on available for sale securities Foreign currency translation adjustments Total Beginning balance $ (1,766 ) $ 86,100 $ (7,628 ) $ 76,706 Other comprehensive (loss) income before reclassifications — (65,941 ) (24,690 ) (90,631 ) Amounts reclassified from accumulated other comprehensive loss (1) 88 (32,797 ) — (32,709 ) Net current period other comprehensive loss 88 (98,738 ) (24,690 ) (123,340 ) Ending balance $ (1,678 ) $ (12,638 ) $ (32,318 ) $ (46,634 ) (1) All amounts are net of tax.
Reclassification Out Of Accumulated Other Comprehensive Loss	The following tables present the significant items reclassified out of accumulated other comprehensive loss during the years ended December 31, 2016 and 2015 : For the Year Ended December 31, 2016 Details about accumulated other comprehensive loss components Amount reclassified from accumulated other comprehensive loss Affected line item in the Consolidated Statements of Income and Comprehensive Income Losses on cash flow hedges - Debt $ 88 Interest expense 88 Total before income taxes — Income tax expense $ 88 Total net of income taxes Unrealized holding losses (gains) on available for sale securities $ 7,984 Net realized and unrealized (losses) gains 10,769 Net impairment losses recognized in earnings 18,753 Total before income taxes 1,081 Income tax expense $ 19,834 Total net of income taxes For the Year Ended December 31, 2015 Details about accumulated other comprehensive loss components Amount reclassified from accumulated other comprehensive loss Affected line item in the Consolidated Statements of Income and Comprehensive Income Losses on cash flow hedges - Debt $ 88 Interest expense 88 Total before income taxes — Income tax expense $ 88 Total net of income taxes Unrealized holding losses (gains) on available for sale securities $ (37,245 ) Net realized and unrealized (losses) gains 3,715 Net impairment losses recognized in earnings (33,530 ) Total before income taxes 733 Income tax benefit $ (32,797 ) Total net of income taxes

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Schedule Of Computation Of Basic And Diluted Earnings Per Share	The following table sets forth the computation of basic and diluted earnings per share for the years ended December 31, 2016 , 2015 and 2014 : 2016 2015 2014 Numerator: Net income available to common and participating common shareholders $ 333,218 $ 311,345 $ 315,700 Less amount allocated to participating common shareholders (1) (6,973 ) (8,749 ) (9,118 ) Net income allocated to common shareholders $ 326,245 $ 302,596 $ 306,582 Denominator: Weighted average shares - basic 65,991,947 52,707,390 43,368,062 Share equivalents: Options 65,351 118,392 47,111 Restricted shares and restricted share units 78,075 2,721 70 Weighted average shares - diluted 66,135,373 52,828,503 43,415,243 Basic earnings per common share $ 4.94 $ 5.74 $ 7.07 Diluted earnings per common share $ 4.93 $ 5.73 $ 7.06 (1) Represents earnings and dividends attributable to holders of unvested restricted shares and restricted share units issued under the Company's stock compensation plans that are considered participating. In periods of loss, no losses are allocated to participating common shareholders (unvested restricted shares and restricted share units).
Schedule Of Dividends Declared	The following table sets forth dividends declared in the years ended December 31, 2016 , 2015 and 2014 , respectively: 2016 2015 2014 Dividends declared per Series A preferred share $ — $ 1.9375 $ 1.9375 Dividends declared per Series B preferred share $ 0.8646 $ 1.8750 $ 1.8750 Dividends declared per Series C preferred share $ 1,680.10 $ — $ — Dividends declared per common share $ 1.52 $ 1.40 $ 1.36

Stock-Based Employee Compensa54

Stock-Based Employee Compensation And Other Stock Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary Of Stock Option Activity	A summary of option activity, including options held by employees, during the year ended December 31, 2016 is presented below: For the year ended December 31, 2016 Options Outstanding Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (years) Aggregate Intrinsic Value Beginning of year 320,000 $ 48.20 Granted — — Exercised (160,000 ) 48.20 Forfeited — — Outstanding, end of year 160,000 $ 48.20 6.41 $ 7,072 Exercisable and vested options, end of year — $ — N/A $ —
Restricted Share And Restricted Share Unit Activity	A summary of the restricted share and restricted share unit activity during the year ended December 31, 2016 , is presented below: Number of Shares/Units Aggregate Intrinsic Value Unvested, beginning of year 1,663,582 Granted 638,217 Settled (769,445 ) Forfeited (65,638 ) Unvested, end of year 1,466,716 Outstanding, end of year 1,466,716 $ 135,525

Statutory Requirements And Di55

Statutory Requirements And Dividend Restrictions (Tables)	12 Months Ended
	Dec. 31, 2016
Statutory Requirements And Dividend Restrictions [Abstract]
Statutory Capital	The combined statutory capital and combined statutory net income (loss) for the Company's principal operating subsidiaries, excluding Syndicate 5151, in their respective jurisdictions were as follows: Statutory capital Bermuda United States U.K. (1) Singapore 2016 2015 2016 2015 2016 2015 2016 2015 Required statutory capital $ 1,614,465 $ 1,276,453 $ 350,947 $ 281,905 $ 184,799 $ 84,086 $ 3,461 $ 3,524 Actual statutory capital 4,525,290 4,307,249 810,704 768,791 451,257 538,265 59,025 49,842 (1) U.K. includes the statutory capital of Endurance U.K.
Statutory Net Income (Loss)	Statutory net income (loss) Bermuda United States U.K. Singapore Year ended December 31, 2016 $ 486,254 $ 64,688 $ 79,912 $ 10,460 Year ended December 31, 2015 417,298 70,398 969 17,542 Year ended December 31, 2014 453,127 28,450 4,135 4,111

Taxes (Tables)

Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Tax Benefit (Expense)	The income tax benefit (expense) was as follows for the years ended December 31, 2016 , 2015 and 2014 , respectively: 2016 2015 2014 Current income tax expense $ (10,993 ) $ (6,262 ) $ (1,804 ) Deferred income tax benefit 11,174 1,900 1,414 Income tax benefit (expense) $ 181 $ (4,362 ) $ (390 )
Schedule Of Effective Income Tax Rate Reconciliation	The actual income tax benefit (expense) attributable to income for the years ended December 31, 2016 , 2015 and 2014 differed from the amount computed by applying the combined effective rate of 0% under Bermuda law to income before income taxes, as a result of the following: 2016 2015 2014 Computed expected tax expense $ — $ — $ — Tax expense effect on foreign taxes (26,149 ) (8,071 ) (1,661 ) Change in valuation allowance 26,330 3,709 1,271 Income tax benefit (expense) $ 181 $ (4,362 ) $ (390 )
Schedule Of Net Deferred Tax Assets And Liabilities	Net deferred income tax assets and liabilities consisted of the following as of December 31, 2016 and 2015 : 2016 2015 Deferred income tax assets: Unearned premiums $ 28,523 $ 25,172 Loss reserves 26,594 27,370 Net operating loss carryforward 66,315 92,844 Deferred compensation 26,451 25,268 Deferred interest 48,359 46,568 Unrealized investment losses 1,803 1,568 Realized investment losses 4,010 4,972 Other 3,830 11,077 Total deferred income tax assets 205,885 234,839 Deferred income tax liabilities: Deferred acquisition costs (1,325 ) (8,179 ) Unrealized foreign exchange gains — (4,087 ) Temporary differences related to acquisition (29,033 ) (35,461 ) Start up costs (1,989 ) (1,565 ) Other (10,002 ) (7,561 ) Total deferred income tax liabilities (42,349 ) (56,853 ) Valuation allowance (104,808 ) (131,138 ) Net deferred income tax asset $ 58,728 $ 46,848
Schedule Of Distribution Of Income Before Income Taxes	The Company's income before income taxes was distributed as follows for the years ended December 31, 2016 , 2015 and 2014 , respectively: 2016 2015 2014 U.S. (domestic) $ 40,872 $ 95,649 $ 60,112 Non-U.S. (foreign) (1) 340,094 263,824 288,728 Income before income taxes $ 380,966 $ 359,473 $ 348,840 (1) The Company's non-U.S. (foreign) operating subsidiaries write business that is exposed to risks originating in the United States.

Condensed Unaudited Quarterly57

Condensed Unaudited Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Summary Of The Unaudited Quarterly Data	The following is a summary of the unaudited quarterly data for the year ended December 31, 2016 : Quarter Ended Quarter Ended Quarter Ended Quarter Ended Net premiums earned $ 553,191 $ 599,608 $ 610,156 $ 600,705 Net investment income 11,181 43,977 62,236 59,196 Net realized and unrealized gains (losses) 13,787 6,347 13,405 (45,958 ) Net impairment losses recognized in earnings (623 ) (9,841 ) (183 ) (122 ) Subtotal $ 577,536 $ 640,091 $ 685,614 $ 613,821 Net losses and loss expenses $ 243,328 $ 376,112 $ 331,462 $ 370,150 Acquisition, general and administrative, and corporate expenses $ 187,838 $ 178,870 $ 201,081 $ 192,546 Net foreign exchange gains $ (11,729 ) $ (32,751 ) $ (18,576 ) $ (11,628 ) Net income $ 124,644 $ 87,628 $ 139,400 $ 29,475 Net income attributable to non-controlling interests (9,063 ) (3,714 ) (5,679 ) (5,674 ) Net income available to Endurance Holdings $ 115,581 $ 83,914 $ 133,721 $ 23,801 Preferred dividends (9,203 ) (7,293 ) (3,651 ) (3,652 ) Net income available to Endurance Holdings' common and participating common shareholders $ 106,378 $ 76,621 $ 130,070 $ 20,149 Basic earnings per share $ 1.58 $ 1.14 $ 1.93 $ 0.30 Diluted earnings per share $ 1.58 $ 1.14 $ 1.92 $ 0.30 The following is a summary of the unaudited quarterly data for the year ended December 31, 2015 : Quarter Ended Quarter Ended Quarter Ended Quarter Ended Net premiums earned $ 389,859 $ 458,135 $ 557,003 $ 573,456 Net investment income 41,861 32,252 16,533 23,180 Net realized and unrealized gains (losses) 18,189 9,680 5,029 (20,238 ) Net impairment losses recognized in earnings (649 ) (424 ) (38 ) (2,604 ) Subtotal $ 449,260 $ 499,643 $ 578,527 $ 573,794 Net losses and loss expenses $ 171,936 $ 239,122 $ 263,993 $ 242,057 Acquisition, general and administrative, and corporate expenses $ 149,251 $ 152,570 $ 225,558 $ 194,726 Net foreign exchange losses (gains) $ 7,552 $ 12,981 $ 8,621 $ (2,190 ) Net income $ 108,479 $ 84,206 $ 54,530 $ 107,896 Net income attributable to non-controlling interests — — (2,707 ) (8,309 ) Net income available to Endurance Holdings $ 108,479 $ 84,206 $ 51,823 $ 99,587 Preferred dividends (8,188 ) (8,188 ) (8,188 ) (8,186 ) Net income available to Endurance Holdings' common and participating common shareholders $ 100,291 $ 76,018 $ 43,635 $ 91,401 Basic earnings per share $ 2.24 $ 1.69 $ 0.73 $ 1.36 Diluted earnings per share $ 2.23 $ 1.68 $ 0.73 $ 1.36

Organization (Narrative) (Detai

Organization (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	Oct. 05, 2016	Dec. 31, 2016	Dec. 31, 2015	Jul. 31, 2015
Noncontrolling Interest [Line Items]
SOMPO acquisition price				$ 69.49
Acquisition transaction costs			$ 19.5
Blue Capital Reinsurance Holdings [Member]
Noncontrolling Interest [Line Items]
Ownership percentage		33.30%
Blue Capital Global Reinsurance Fund [Member]
Noncontrolling Interest [Line Items]
Ownership percentage		25.20%
SOMPO
Noncontrolling Interest [Line Items]
Percentage of outstanding ordinary shares acquired	100.00%
SOMPO acquisition price	$ 93
Aggregate consideration	$ 6,304
Loss on Contract Termination	204.9
Acquisition transaction costs	$ 15.8

Summary Of Significant Accoun59

Summary Of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Significant Accounting Policies [Line Items]
Premiums Earned LO Duration	12 months
Premiums Earned Risk Attaching Duration	24 months
Allowance for estimated uncollectible premiums receivable	$ 6.2	$ 7.4
Vesting period for employee awards	4 years
Restricted share awards to non-employee directors, vesting period	1 year
High
Significant Accounting Policies [Line Items]
Cash equivalents maturity, in days	90 days
Short-term investments maturity, in days	1 year
Low
Significant Accounting Policies [Line Items]
Short-term investments maturity, in days	90 days

Acquisition of Montpelier (Narr

Acquisition of Montpelier (Narrative) (Details) $ / shares in Units, $ in Thousands	Jul. 31, 2015USD ($)states$ / sharesshares	Dec. 31, 2015USD ($)
Business Acquisition [Line Items]
Total Company ordinary shares | shares	20,686,699
Total value of Company ordinary shares	$ 1,437,519
Special dividend paid per Montpelier common share and restricted share unit | $ / shares	$ 9.89
Acquisition transaction and integration related expenses		$ 76,600
Acquisition transaction costs		19,500
Integration related costs		4,400
Compensation related costs		$ 52,700
Measurement period for a business combination, in months	12 months
Number of States in which Entity Operates | states	15
Montpelier [Member]
Business Acquisition [Line Items]
Total special dividend consideration paid to Montpelier common shareholders and Montpelier equity award holders	$ 451,101

Acquisition of Montpelier (Purc

Acquisition of Montpelier (Purchase Price) (Details) - USD ($) $ / shares in Units, $ in Thousands		Jul. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Number of Montpelier common shares outstanding immediately prior to the closing of the acquisition			67,627,901	66,797,991
Exchange ratio		0.472
Total Company ordinary shares		20,686,699
Company ordinary share closing price on July 31, 2015		$ 69.49
Total value of Company ordinary shares		$ 1,437,519
Fair value of restricted share units attributable to service period prior to Closing Date(1)	[1]	33,327
Total consideration		$ 1,470,846
Special dividend paid per Montpelier common share and restricted share unit		$ 9.89
Total consideration received by Montpelier common shareholders and Montpelier equity award holders		$ 1,921,947
Net purchase price		$ 1,470,846
Montpelier [Member]
Business Acquisition [Line Items]
Number of Montpelier common shares outstanding immediately prior to the closing of the acquisition		43,827,753
Number of Montpelier common shares and restricted share units eligible for special dividend		45,611,810
Total special dividend consideration paid to Montpelier common shareholders and Montpelier equity award holders		$ (451,101)
[1]	Outstanding Montpelier restricted share units were assumed by the Company and adjusted as of the Closing Date to represent the right to receive 0.472 Company ordinary shares for each outstanding Montpelier restricted share unit rounded down to the next whole number of Company ordinary shares. The fair value of the Montpelier restricted share units was determined based on the closing price of the Company's ordinary shares on the Closing Date. The resulting fair value of the restricted share units was apportioned as purchase consideration based on service provided to Montpelier as of the Closing Date with the remaining fair value of these restricted share units to be recognized prospectively over the restricted share units' remaining vesting period.

Acquisition of Montpelier (Fair

Acquisition of Montpelier (Fair Value of Net Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	Jul. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Montpelier shareholders' equity attributable to controlling interest prior to Special Dividend		$ 4,882,439	$ 4,856,262	$ 3,185,182
Fixed maturity investments, trading at fair value	$ (11,100)
Deferred acquisition costs	(91,713)
Reinsurance recoverable on unpaid losses	(675)
Other assets	(12,459)
Reserve for losses and loss expenses	10,822
Debt	21,123
Deferred tax liability	(18,346)
Non-controlling interest	25,615
Total adjustments for fair value by applicable balance sheet caption	$ (76,733)
Estimated total consideration over the fair value of net assets acquired assigned to goodwill		$ 175,482	$ 176,455	$ 91,238
Weighted average useful life of acquired finite-lived intangible assets	8 years
Total adjustments for fair value by applicable balance sheet caption and identifiable intangible assets	$ 274,067
Estimated fair value of net assets acquired and identifiable intangible assets	1,383,221
Total consideration paid by Endurance Holdings	1,470,846
Montpelier [Member]
Business Acquisition [Line Items]
Montpelier shareholders' equity attributable to controlling interest prior to Special Dividend	1,560,255
Cash and cash equivalents (Special Dividend on Montpelier common shares and Montpelier equity awards)	(451,101)
Adjusted shareholders' equity of Montpelier as of July 31, 2015	1,109,154
Identifiable finite lived intangible assets (non-contractual relationships, Lloyd's syndicate distribution channel, renewal rights, value of business acquired (VOBA), trade names, non-compete agreements and asset management agreements)	293,200
Estimated total consideration over the fair value of net assets acquired assigned to goodwill	87,625
Identifiable indefinite lived intangible assets (insurance licenses, Lloyd's syndicate capacity and asset management agreements)	$ 57,600

Acquisition of Montpelier (Inta

Acquisition of Montpelier (Intangible Assets) (Details) $ in Thousands	Jul. 31, 2015USD ($)
Business Acquisition [Line Items]
Identifiable intangible assets at July 31, 2015	$ 350,800
Key non-contractual relationships
Business Acquisition [Line Items]
Finite lived intangible assets acquired	$ 71,800
Finite-Lived Intangible Asset, Useful Life	10 years
Other non-contractual relationships
Business Acquisition [Line Items]
Finite lived intangible assets acquired	$ 22,400
Finite-Lived Intangible Asset, Useful Life	3 years
Trade names
Business Acquisition [Line Items]
Finite lived intangible assets acquired	$ 1,800
Insurance licenses
Business Acquisition [Line Items]
Indefinite lived intangible assets acquired	1,900
Non-compete agreements
Business Acquisition [Line Items]
Finite lived intangible assets acquired	5,700
Lloyd's syndicate capacity
Business Acquisition [Line Items]
Indefinite lived intangible assets acquired	48,300
Lloyd's syndicate distribution channel
Business Acquisition [Line Items]
Finite lived intangible assets acquired	$ 18,400
Finite-Lived Intangible Asset, Useful Life	10 years
Renewal rights
Business Acquisition [Line Items]
Finite lived intangible assets acquired	$ 82,100
Finite-Lived Intangible Asset, Useful Life	15 years
VOBA
Business Acquisition [Line Items]
Finite lived intangible assets acquired	$ 88,400
Finite-Lived Intangible Asset, Useful Life	2 years
Asset management agreements
Business Acquisition [Line Items]
Indefinite lived intangible assets acquired	$ 10,000

Acquisition of Montpelier (Fina

Acquisition of Montpelier (Financial Results) (Details) - USD ($) $ in Thousands		5 Months Ended	12 Months Ended
		Dec. 31, 2015	Dec. 31, 2015
Business Acquisition [Line Items]
Compensation related costs			$ 52,700
Montpelier [Member]
Business Acquisition [Line Items]
Total revenues		$ 225,899
Net income attributable to the Company's common shareholders(1)	[1]	$ 54,768
[1]	Includes $52.7 million of compensation-related costs associated with terminating employees of Montpelier.

Acquisition of Montpelier (Supp

Acquisition of Montpelier (Supplemental Proforma Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Business Combinations [Abstract]
Total revenues	$ 2,452,410	$ 2,668,604
Net income available to Endurance Holdings' common shareholders	$ 443,817	$ 388,371

Investments (Narrative) (Detail

Investments (Narrative) (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016USD ($)positions	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)positions	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)positions	Dec. 31, 2015USD ($)positions	Dec. 31, 2014USD ($)
Investments [Abstract]
Number of available for sale securities in an unrealized loss position | positions	1,090				1,310				1,090	1,310
Number of securities in a continuous unrealized loss position for twelve months or greater | positions	218				158				218	158
Unrealized losses	$ (37,400)				$ (72,600)				$ (37,400)	$ (72,600)
Unrealized losses, 12 months or greater	(9,400)				(12,700)				(9,400)	(12,700)
Net impairment losses recognized in earnings	$ 122	$ 183	$ 9,841	$ 623	$ 2,604	$ 38	$ 424	$ 649	$ 10,769	$ 3,715	$ 625

Investments (Composition Of Net

Investments (Composition Of Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Investment Income [Line Items]
Gross investment income									$ 193,115	$ 130,312	$ 145,827
Investment expenses									(16,525)	(16,486)	(14,284)
Net investment income	$ 59,196	$ 62,236	$ 43,977	$ 11,181	$ 23,180	$ 16,533	$ 32,252	$ 41,861	176,590	113,826	131,543
Total fixed income investments
Net Investment Income [Line Items]
Gross investment income									165,210	132,786	118,084
Equity securities
Net Investment Income [Line Items]
Gross investment income									12,639	8,209	5,689
Other investments
Net Investment Income [Line Items]
Gross investment income									12,442	(13,553)	19,609
Cash and Cash Equivalents [Member]
Net Investment Income [Line Items]
Gross investment income									$ 2,824	$ 2,870	$ 2,445

Investments (Contractual Maturi

Investments (Contractual Maturities Of Fixed Income Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale and Trading Securities [Line Items]
Due within one year, amortized cost	$ 617,655	$ 622,070
Due within one year, fair value	617,462	622,248
Due after one year through five years, amortized cost	2,170,111	2,005,456
Due after one year through five years, fair value	2,187,173	1,995,502
Due after five years through ten years, amortized cost	887,775	683,147
Due after five years through ten years, fair value	896,388	676,932
Due after ten years, amortized cost	55,400	33,168
Due after ten years, fair value	58,449	34,651
Residential mortgage-backed securities
Schedule of Available-for-sale and Trading Securities [Line Items]
No single maturity date, amortized cost	1,448,917	1,301,083
No single maturity date, fair value	1,461,286	1,311,373
Fixed income investments, fair value	1,461,286	1,311,373
Commercial mortgage-backed securities
Schedule of Available-for-sale and Trading Securities [Line Items]
No single maturity date, amortized cost	615,730	817,570
No single maturity date, fair value	618,848	812,886
Fixed income investments, fair value	618,848	812,886
Collateralized loan and debt obligations
Schedule of Available-for-sale and Trading Securities [Line Items]
No single maturity date, amortized cost	369,126	419,795
No single maturity date, fair value	371,256	405,128
Fixed income investments, fair value	371,256	405,128
Asset-backed securities
Schedule of Available-for-sale and Trading Securities [Line Items]
No single maturity date, amortized cost	509,595	510,540
No single maturity date, fair value	510,663	507,255
Fixed income investments, fair value	510,663	507,255
Total fixed income investments
Schedule of Available-for-sale and Trading Securities [Line Items]
Fixed income investments, amortized cost	6,674,309	6,392,829
Fixed income investments, fair value	$ 6,721,525	$ 6,365,975

Investments Investments (Fair V

Investments Investments (Fair Value of Trading Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Trading Securities [Line Items]
Fixed maturity investments, trading at fair value	$ 2,740,055	$ 1,587,160
Short-term investments, trading at fair value	330,199	394,111
Equity securities, trading at fair value	16,056	15,229
U.S. government and agencies securities
Schedule of Trading Securities [Line Items]
Fixed maturity investments, trading at fair value	551,055	319,674
U.S. state and municipal securities
Schedule of Trading Securities [Line Items]
Fixed maturity investments, trading at fair value	6,006	5,559
Foreign government securities
Schedule of Trading Securities [Line Items]
Fixed maturity investments, trading at fair value	110,088	49,861
Government guaranteed corporate securities
Schedule of Trading Securities [Line Items]
Fixed maturity investments, trading at fair value	2,959	38,201
Corporate securities
Schedule of Trading Securities [Line Items]
Fixed maturity investments, trading at fair value	1,051,200	532,192
Residential mortgage-backed securities
Schedule of Trading Securities [Line Items]
Fixed maturity investments, trading at fair value	483,444	258,574
Commercial mortgage-backed securities
Schedule of Trading Securities [Line Items]
Fixed maturity investments, trading at fair value	164,237	127,124
Collateralized loan and debt obligations
Schedule of Trading Securities [Line Items]
Fixed maturity investments, trading at fair value	98,924	103,219
Asset-backed securities
Schedule of Trading Securities [Line Items]
Fixed maturity investments, trading at fair value	272,142	152,756
Total fixed maturity investments
Schedule of Trading Securities [Line Items]
Fixed maturity investments, trading at fair value	2,740,055	1,587,160
Total fixed income investments
Schedule of Trading Securities [Line Items]
Fixed maturity investments, trading at fair value	3,070,254	1,981,271
Equity investments
Schedule of Trading Securities [Line Items]
Equity securities, trading at fair value	16,056	14,676
Preferred equity investments
Schedule of Trading Securities [Line Items]
Equity securities, trading at fair value	$ 0	$ 553

Investments (Other Investments)

Investments (Other Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Market Value	$ 588,308	$ 872,617
Unfunded Commitments	92,214	102,070
Ineligible for redemption in next year	189,932	163,524
Alternative Funds [Member]
Schedule of Equity Method Investments [Line Items]
Market Value	588,308	809,121
Unfunded Commitments	92,214	102,070
Ineligible for redemption in next year	189,932	163,524
Hedge funds
Schedule of Equity Method Investments [Line Items]
Market Value	482,865	704,966
Unfunded Commitments	0	0
Ineligible for redemption in next year	85,963	57,876
Private investment funds
Schedule of Equity Method Investments [Line Items]
Market Value	76,451	80,690
Unfunded Commitments	92,214	102,070
Ineligible for redemption in next year	76,451	80,690
Other investment funds
Schedule of Equity Method Investments [Line Items]
Market Value	28,992	23,465
Unfunded Commitments	0	0
Ineligible for redemption in next year	$ 27,518	24,958
Specialty Funds [Member]
Schedule of Equity Method Investments [Line Items]
Market Value		63,496
Unfunded Commitments		0
Ineligible for redemption in next year		0
High yield loan funds
Schedule of Equity Method Investments [Line Items]
Market Value		63,496
Unfunded Commitments		0
Ineligible for redemption in next year		$ 0

Investments (Other Investments

Investments (Other Investments Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Other investments, invested amount	$ 470,300	$ 737,100
Market Value	588,308	872,617
Alternative Funds [Member]
Schedule of Equity Method Investments [Line Items]
Market Value	588,308	809,121
Hedge funds
Schedule of Equity Method Investments [Line Items]
Market Value	$ 482,865	704,966
Estimated liquidation, percentage in next 12 months	82.20%
Hedge funds | Low
Schedule of Equity Method Investments [Line Items]
Estimated notice period, in days	30 days
Hedge funds | High
Schedule of Equity Method Investments [Line Items]
Estimated notice period, in days	90 days
Private investment funds
Schedule of Equity Method Investments [Line Items]
Market Value	$ 76,451	80,690
Private investment funds | Low
Schedule of Equity Method Investments [Line Items]
Estimated liquidation period, in years	5 years
Private investment funds | High
Schedule of Equity Method Investments [Line Items]
Estimated liquidation period, in years	10 years
Specialty Funds [Member]
Schedule of Equity Method Investments [Line Items]
Market Value		63,496
High yield loan funds
Schedule of Equity Method Investments [Line Items]
Market Value		$ 63,496
High yield loan funds | Low
Schedule of Equity Method Investments [Line Items]
Estimated notice period, in days	30 days
High yield loan funds | High
Schedule of Equity Method Investments [Line Items]
Estimated notice period, in days	90 days

Investments (Net Realized And U

Investments (Net Realized And Unrealized Gains) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investments [Abstract]
Gross realized gains on investment sales										$ 39,033	$ 65,881	$ 35,921
Gross realized losses on investment sales										(61,752)	(28,636)	(16,515)
Net unrealized gains (losses) on trading securities										12,480	(24,257)	0
Intangible asset impairment loss	[1]									0	0	(5,450)
Change in fair value of derivative financial instruments	[2]									(2,180)	(328)	327
Net realized and unrealized (losses) gains		$ (45,958)	$ 13,405	$ 6,347	$ 13,787	$ (20,238)	$ 5,029	$ 9,680	$ 18,189	$ (12,419)	$ 12,660	$ 14,283
[1]	For additional information on the Company's intangible assets, see Note 11, Goodwill and intangible assets.
[2]	For additional information on the Company's derivative financial instruments, see Note 9, Derivatives.

Investments (Amortized Cost, Fa

Investments (Amortized Cost, Fair Value And Unrealized Gains And Losses Classified As Available For Sale) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Fixed income investments, amortized cost	$ 3,538,227	$ 4,361,997
Fixed income investments, fair value	3,572,766	4,359,019
Equity securities, cost	461,684	542,429
Equity securities, fair value	485,085	513,585
U.S. government and agencies securities
Schedule of Available-for-sale Securities [Line Items]
Fixed income investments, amortized cost	449,638	499,386
Fixed income investments, gross unrealized gains	3,981	2,561
Fixed income investments, gross unrealized losses	(2,792)	(3,153)
Fixed income investments, fair value	450,827	498,794
U.S. state and municipal securities
Schedule of Available-for-sale Securities [Line Items]
Fixed income investments, amortized cost	11,560	16,908
Fixed income investments, gross unrealized gains	945	120
Fixed income investments, gross unrealized losses	(154)	(181)
Fixed income investments, fair value	12,351	16,847
Foreign government securities
Schedule of Available-for-sale Securities [Line Items]
Fixed income investments, amortized cost	68,539	110,893
Fixed income investments, gross unrealized gains	2,236	803
Fixed income investments, gross unrealized losses	(1,944)	(581)
Fixed income investments, fair value	68,831	111,115
Government guaranteed corporate securities
Schedule of Available-for-sale Securities [Line Items]
Fixed income investments, amortized cost	912	19,248
Fixed income investments, gross unrealized gains	46	311
Fixed income investments, gross unrealized losses	0	(7)
Fixed income investments, fair value	958	19,552
Corporate securities
Schedule of Available-for-sale Securities [Line Items]
Fixed income investments, amortized cost	1,078,756	1,323,276
Fixed income investments, gross unrealized gains	26,481	5,698
Fixed income investments, gross unrealized losses	(8,744)	(11,232)
Fixed income investments, fair value	1,096,493	1,317,742
Residential mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Fixed income investments, amortized cost	968,273	1,041,540
Fixed income investments, gross unrealized gains	21,032	16,400
Fixed income investments, gross unrealized losses	(11,463)	(5,141)
Fixed income investments, fair value	977,842	1,052,799
Commercial mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Fixed income investments, amortized cost	452,011	689,078
Fixed income investments, gross unrealized gains	8,790	4,737
Fixed income investments, gross unrealized losses	(6,190)	(8,053)
Fixed income investments, fair value	454,611	685,762
Collateralized loan and debt obligations
Schedule of Available-for-sale Securities [Line Items]
Fixed income investments, amortized cost	271,361	304,915
Fixed income investments, gross unrealized gains	1,644	796
Fixed income investments, gross unrealized losses	(673)	(3,802)
Fixed income investments, fair value	272,332	301,909
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Fixed income investments, amortized cost	237,177	356,753
Fixed income investments, gross unrealized gains	2,242	585
Fixed income investments, gross unrealized losses	(898)	(2,839)
Fixed income investments, fair value	238,521	354,499
Total fixed maturity investments
Schedule of Available-for-sale Securities [Line Items]
Fixed income investments, amortized cost	3,538,227	4,361,997
Fixed income investments, gross unrealized gains	67,397	32,011
Fixed income investments, gross unrealized losses	(32,858)	(34,989)
Fixed income investments, fair value	3,572,766	4,359,019
Short-term investments
Schedule of Available-for-sale Securities [Line Items]
Fixed income investments, amortized cost	78,506	25,657
Fixed income investments, gross unrealized gains	1	28
Fixed income investments, gross unrealized losses	(2)	0
Fixed income investments, fair value	78,505	25,685
Total fixed income investments
Schedule of Available-for-sale Securities [Line Items]
Fixed income investments, amortized cost	3,616,733	4,387,654
Fixed income investments, gross unrealized gains	67,398	32,039
Fixed income investments, gross unrealized losses	(32,860)	(34,989)
Fixed income investments, fair value	3,651,271	4,384,704
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Equity securities, cost	461,684	542,429
Equity securities, gross unrealized gains	27,948	8,781
Equity securities, gross unrealized loss	(4,547)	(37,625)
Equity securities, fair value	485,085	513,585
Equity investments
Schedule of Available-for-sale Securities [Line Items]
Equity securities, cost	461,509	527,154
Equity securities, gross unrealized gains	27,948	6,835
Equity securities, gross unrealized loss	(4,545)	(37,474)
Equity securities, fair value	484,912	496,515
Preferred equity investments
Schedule of Available-for-sale Securities [Line Items]
Equity securities, cost	175	15,275
Equity securities, gross unrealized gains	0	1,946
Equity securities, gross unrealized loss	(2)	(151)
Equity securities, fair value	$ 173	$ 17,070

Investments (Available For Sale

Investments (Available For Sale Securities In An Unrealized Loss Position) (Details) - USD ($) $ in Thousands		Dec. 31, 2016		Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, 12 months or greater		$ (9,400)		$ (12,700)
Unrealized losses		(37,400)		(72,600)
U.S. government and agencies securities
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months		(2,791)	[1]	(2,175)	[2]
Fair value, less than 12 months		289,012		347,024
Unrealized losses, 12 months or greater		(1)	[1]	(978)	[2]
Fair value, 12 months or greater		248		16,669
Unrealized losses		(2,792)	[1]	(3,153)	[2]
Fair value		289,260		363,693
U.S. state and municipal securities
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months		(152)	[1]	(96)	[2]
Fair value, less than 12 months		5,288		9,662
Unrealized losses, 12 months or greater		(2)	[1]	(85)	[2]
Fair value, 12 months or greater		2,143		695
Unrealized losses		(154)	[1]	(181)	[2]
Fair value		7,431		10,357
Foreign government securities
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months		(446)	[1]	(404)	[2]
Fair value, less than 12 months		15,717		31,881
Unrealized losses, 12 months or greater		(1,498)	[1]	(177)	[2]
Fair value, 12 months or greater		5,973		3,966
Unrealized losses		(1,944)	[1]	(581)	[2]
Fair value		21,690		35,847
Government guaranteed corporate securities
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months	[2]			(7)
Fair value, less than 12 months				1,692
Unrealized losses, 12 months or greater	[2]			0
Fair value, 12 months or greater				0
Unrealized losses	[2]			(7)
Fair value				1,692
Corporate securities
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months		(7,512)	[1]	(9,222)	[2]
Fair value, less than 12 months		448,643		830,349
Unrealized losses, 12 months or greater		(1,232)	[1]	(2,010)	[2]
Fair value, 12 months or greater		11,897		51,024
Unrealized losses		(8,744)	[1]	(11,232)	[2]
Fair value		460,540		881,373
Residential mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months		(10,082)	[1]	(3,378)	[2]
Fair value, less than 12 months		521,167		365,082
Unrealized losses, 12 months or greater		(1,381)	[1]	(1,763)	[2]
Fair value, 12 months or greater		31,835		79,355
Unrealized losses		(11,463)	[1]	(5,141)	[2]
Fair value		553,002		444,437
Commercial mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months		(3,453)	[1]	(6,708)	[2]
Fair value, less than 12 months		174,144		436,387
Unrealized losses, 12 months or greater		(2,737)	[1]	(1,345)	[2]
Fair value, 12 months or greater		76,694		42,246
Unrealized losses		(6,190)	[1]	(8,053)	[2]
Fair value		250,838		478,633
Collateralized loan and debt obligations
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months		(223)	[1]	(3,107)	[2]
Fair value, less than 12 months		50,194		224,520
Unrealized losses, 12 months or greater		(450)	[1]	(695)	[2]
Fair value, 12 months or greater		81,043		48,167
Unrealized losses		(673)	[1]	(3,802)	[2]
Fair value		131,237		272,687
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months		(539)	[1]	(2,624)	[2]
Fair value, less than 12 months		64,109		311,814
Unrealized losses, 12 months or greater		(359)	[1]	(215)	[2]
Fair value, 12 months or greater		39,770		12,880
Unrealized losses		(898)	[1]	(2,839)	[2]
Fair value		103,879		324,694
Total fixed maturity investments
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months	[1]	(25,198)
Fair value, less than 12 months		1,568,274
Unrealized losses, 12 months or greater	[1]	(7,660)
Fair value, 12 months or greater		249,603
Unrealized losses	[1]	(32,858)
Fair value		1,817,877
Short-term investments
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months	[1]	(2)
Fair value, less than 12 months		4,691
Unrealized losses, 12 months or greater	[1]	0
Fair value, 12 months or greater		0
Unrealized losses	[1]	(2)
Fair value		4,691
Total fixed income investments
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months		(25,200)	[1]	(27,721)	[2]
Fair value, less than 12 months		1,572,965		2,558,411
Unrealized losses, 12 months or greater		(7,660)	[1]	(7,268)	[2]
Fair value, 12 months or greater		249,603		255,002
Unrealized losses		(32,860)	[1]	(34,989)	[2]
Fair value		1,822,568		2,813,413
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months		(2,857)	[1]	(32,172)	[2]
Fair value, less than 12 months		71,632		336,641
Unrealized losses, 12 months or greater		(1,690)	[1]	(5,453)	[2]
Fair value, 12 months or greater		17,408		56,421
Unrealized losses		(4,547)	[1]	(37,625)	[2]
Fair value		89,040		393,062
Equity investments
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months		(2,855)	[1]	(32,021)	[2]
Fair value, less than 12 months		71,509		329,280
Unrealized losses, 12 months or greater		(1,690)	[1]	(5,453)	[2]
Fair value, 12 months or greater		17,408		56,421
Unrealized losses		(4,545)	[1]	(37,474)	[2]
Fair value		88,917		385,701
Preferred equity investments
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses, less than 12 months		(2)	[1]	(151)	[2]
Fair value, less than 12 months		123		7,361
Unrealized losses, 12 months or greater		0	[1]	0	[2]
Fair value, 12 months or greater		0		0
Unrealized losses		(2)	[1]	(151)	[2]
Fair value		$ 123		$ 7,361
[1]	Gross unrealized losses include unrealized losses on non-OTTI and non-credit OTTI securities recognized in accumulated other comprehensive loss at December 31, 2016.
[2]	Gross unrealized losses include unrealized losses on non-OTTI and non-credit OTTI securities recognized in accumulated other comprehensive loss at December 31, 2015.

Investments Investments (Noncon

Investments Investments (Noncontrolling Interests Rollforward) (Details) - USD ($) $ in Thousands		3 Months Ended								5 Months Ended	12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Noncontrolling Interest [Line Items]
Non-controlling interests, beginning balance					$ 267,810				$ 0	$ 258,529	$ 267,810	$ 0
Net income attributable to non-controlling interests		$ 5,674	$ 5,679	$ 3,714	$ 9,063	$ 8,309	$ 2,707	$ 0	$ 0	11,016	24,130	11,016	$ 0
Net preferred share redemption attributable to third-party investments in the BCGR Cell										20	(19,727)
Non-controlling interests - ending balance		$ 259,694				$ 267,810				267,810	259,694	$ 267,810	$ 0
Blue Capital Reinsurance Holdings [Member]
Noncontrolling Interest [Line Items]
Net income attributable to non-controlling interests										5,490	9,553
Net preferred share redemption attributable to third-party investments in the BCGR Cell										20	72
Dividends declared by BCRH attributable to non-controlling interests										(1,755)	$ (12,519)
Ownership percentage											33.30%
Blue Capital Global Reinsurance Fund [Member]
Noncontrolling Interest [Line Items]
Net income attributable to non-controlling interests										5,526	$ 14,577
Net preferred share redemption attributable to third-party investments in the BCGR Cell	[1]									$ 0	$ (19,799)
Ownership percentage											25.20%
Blue Capital Global Reinsurance Fund [Member] | High
Noncontrolling Interest [Line Items]
Ownership percentage											50.00%
[1]	The redemption from the BCGR Cell was required to fund expenses, repay debt and fund dividends by BCGR.

Fair Value Measurement (Narrati

Fair Value Measurement (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Transfers into Level 3	$ 79,332	$ 131,215
Transfers out of Level 3	(7,267)	(12,405)
Amount of transfers from Level 1 to Level 2	$ 18,400	$ 11,800
Seven Percent Senior Notes [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Senior Notes, stated interest rate	7.00%
Four Point Seven Percent Senior Notes [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Senior Notes, stated interest rate	4.70%
Significant Unobservable Inputs (Level 3)
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Percentage of level 3 assets	3.00%	2.20%
Total fixed maturity investments
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Transfers into Level 3	$ 79,332	$ 131,215
Transfers out of Level 3	$ (7,267)	$ (12,405)

Fair Value Measurement (Schedul

Fair Value Measurement (Schedule Of Available For Sale Investments, Other Assets And Liabilities, and Debt Measured On A Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	$ 408,704	$ 419,796
Other assets (see Note 9)	166,716	68,892
Total assets	7,389,382	6,963,681
Other liabilities (see Note 9)	84,069	46,088
Debt	770,704	737,974
Total liabilities	854,773	784,062
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Other assets (see Note 9)	1,953	4
Total assets	238,031	312,831
Other liabilities (see Note 9)	2,772	0
Debt	0	0
Total liabilities	2,772	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	408,654	419,796
Other assets (see Note 9)	123,681	27,385
Total assets	6,930,582	6,496,894
Other liabilities (see Note 9)	55,051	4,059
Debt	770,704	737,974
Total liabilities	825,755	742,033
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	50	0
Other assets (see Note 9)	41,082	41,503
Total assets	220,769	153,956
Other liabilities (see Note 9)	26,246	42,029
Debt	0	0
Total liabilities	26,246	42,029
U.S. government and agencies securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	1,001,882	818,468
U.S. government and agencies securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	51,827	37,741
U.S. government and agencies securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	950,055	780,727
U.S. government and agencies securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
U.S. state and municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	18,357	22,406
U.S. state and municipal securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
U.S. state and municipal securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	18,357	22,406
U.S. state and municipal securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
Foreign government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	178,919	160,976
Foreign government securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
Foreign government securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	178,919	160,976
Foreign government securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
Government guaranteed corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	3,917	57,753
Government guaranteed corporate securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
Government guaranteed corporate securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	3,917	57,753
Government guaranteed corporate securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	2,147,693	1,849,934
Corporate securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
Corporate securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	1,968,056	1,739,002
Corporate securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	179,637	110,932
Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	1,461,286	1,311,373
Residential mortgage-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
Residential mortgage-backed securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	1,461,286	1,311,373
Residential mortgage-backed securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	618,848	812,886
Commercial mortgage-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
Commercial mortgage-backed securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	618,848	812,174
Commercial mortgage-backed securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	712
Collateralized loan and debt obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	371,256	405,128
Collateralized loan and debt obligations | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
Collateralized loan and debt obligations | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	371,256	404,319
Collateralized loan and debt obligations | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	809
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	510,663	507,255
Asset-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
Asset-backed securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	510,663	507,255
Asset-backed securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	0	0
Total fixed maturity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	6,312,821	5,946,179
Total fixed maturity investments | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	51,827	37,741
Total fixed maturity investments | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	6,081,357	5,795,985
Total fixed maturity investments | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity investments	179,637	112,453
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	501,141	528,814
Equity securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	184,251	275,086
Equity securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	316,890	253,728
Equity securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	0	0
Equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	500,968	511,191
Equity investments | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	184,251	275,086
Equity investments | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	316,717	236,105
Equity investments | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	0	0
Preferred equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	173	17,623
Preferred equity investments | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	0	0
Preferred equity investments | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	173	17,623
Preferred equity investments | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	$ 0	$ 0

Fair Value Measurement (Quantat

Fair Value Measurement (Quantative Information Used As Level 3 Inputs) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)Category
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Derivatives recorded in other assets, fair value	$ 166,716	$ 68,892
Derivatives recorded in other liabilities, fair value	84,069	46,088
Net weather and energy related derivative liabilities	82,647	22,804
Significant Unobservable Inputs (Level 3)
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Derivatives recorded in other assets, fair value	41,082	41,503
Derivatives recorded in other liabilities, fair value	26,246	42,029
Energy and weather contracts
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Derivatives recorded in other assets, fair value	43,035	41,507
Derivatives recorded in other liabilities, fair value	29,018	42,029
Energy and weather contracts | Significant Unobservable Inputs (Level 3)
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Net weather and energy related derivative liabilities	$ 14,836	$ 526
Valuation Techniques | Low | Energy and weather contracts | Significant Unobservable Inputs (Level 3)
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Correlation	0	0
Fair Value Inputs Temperature	-15F	-15F
Fair Value Inputs Composite Weather Variable	-25 deg.	-25 deg.
Fair Value Inputs Rainfall	0"	0"
Fair Value Inputs Windspeed	0.01 m/s	0.01 m/s
Fair Value Inputs Snowfall		0"
Fair Value Inputs Wave Height	0 m
Commodity curve	$ (1)	$ 0
Valuation Techniques | High | Energy and weather contracts | Significant Unobservable Inputs (Level 3)
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Correlation	1	1
Fair Value Inputs Temperature	115F	115F
Fair Value Inputs Composite Weather Variable	45 deg.	45 deg.
Fair Value Inputs Rainfall	2"	2"
Fair Value Inputs Windspeed	25 m/s	25 m/s
Fair Value Inputs Snowfall		18"
Fair Value Inputs Cyclone Category | Category		5
Fair Value Inputs Wave Height	25 m
Commodity curve	$ 14	$ 13

Fair Value Measurement (Reconci

Fair Value Measurement (Reconciliation Of The Beginning And Ending Balances For All Fixed Maturity Investments Measured At Fair Value On A Recurring Basis Using Level 3) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Level 3, beginning of year	$ 153,956	$ 37,905
Total equity income and losses and realized and unrealized gains and losses included in earnings	4,321	(2,785)
Total income and losses included in other underwriting loss	5,796	(2,951)
Change in unrealized gains and losses included in other comprehensive (loss) income	263	(180)
Purchases	48,572	4,763
Issues	22,571	21,559
Sales	(57,987)	(15,695)
Settlements	(28,788)	(7,470)
Transfers into Level 3	79,332	131,215
Transfers out of Level 3	(7,267)	(12,405)
Level 3, end of year	220,769	153,956
Fixed maturity investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Level 3, beginning of year	112,453	12,290
Total equity income and losses and realized and unrealized gains and losses included in earnings	4,321	(2,785)
Total income and losses included in other underwriting loss	0	0
Change in unrealized gains and losses included in other comprehensive (loss) income	263	(180)
Purchases	48,572	13
Issues	0	0
Sales	(57,987)	(15,695)
Settlements	0	0
Transfers into Level 3	79,332	131,215
Transfers out of Level 3	(7,267)	(12,405)
Level 3, end of year	179,687	112,453
Other assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Level 3, beginning of year	41,503	25,615
Total equity income and losses and realized and unrealized gains and losses included in earnings	0	0
Total income and losses included in other underwriting loss	5,796	(2,951)
Change in unrealized gains and losses included in other comprehensive (loss) income	0	0
Purchases	0	4,750
Issues	22,571	21,559
Sales	0	0
Settlements	(28,788)	(7,470)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Level 3, end of year	41,082	41,503
Other liabilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Level 3, beginning of year	(42,029)	(35,366)
Total equity income and losses and realized and unrealized gains and losses included in earnings	0	0
Total income and losses included in other underwriting loss	90	5,062
Change in unrealized gains and losses included in other comprehensive (loss) income	0	0
Purchases	0	(4,231)
Issues	(34,219)	(34,114)
Sales	0	0
Settlements	49,912	26,620
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Level 3, end of year	$ (26,246)	$ (42,029)

Reserve For Losses And Loss E80

Reserve For Losses And Loss Expenses (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred related to Prior years	$ (221,550)	$ (243,464)	$ (233,815)
Proportional Reinsurance Contracts
Liability for Claims and Claims Adjustment Expense [Line Items]
IBNR reserves	700,000
Reinsurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred related to Prior years	144,400	161,500	153,200
Insurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred related to Prior years	$ 77,100	$ 82,000	$ 80,600

Reserve For Losses And Loss E81

Reserve For Losses And Loss Expenses ( Activity in Reserve For Losses And Loss Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Insurance Loss Reserves [Abstract]
Gross reserve for losses and loss expenses, January 1	$ 4,510,415	$ 3,846,859	$ 4,002,259
Reinsurance recoverable on unpaid losses	907,944	670,795	593,755
Net reserve for losses and loss expenses, January 1	3,602,471	3,176,064	3,408,504
Incurred related to Current year	1,542,602	1,160,572	1,203,977
Incurred related to Prior years	(221,550)	(243,464)	(233,815)
Total incurred	1,321,052	917,108	970,162
Paid related to Current year	(295,863)	(265,898)	(439,169)
Paid related to Prior years	(890,027)	(867,739)	(719,043)
Total paid	(1,185,890)	(1,133,637)	(1,158,212)
Amounts acquired(1)	0	675,019	0
Foreign currency translation and other	(45,624)	(32,083)	(44,390)
Net reserve for losses and loss expenses, December 31	3,692,009	3,602,471	3,176,064
Reinsurance recoverable on unpaid losses	1,213,129	907,944	670,795
Gross reserve for losses and loss expenses, December 31	$ 4,905,138	$ 4,510,415	$ 3,846,859

Reserve For Losses And Loss E82

Reserve For Losses And Loss Expenses (Claims Development - Insurance) (Details) $ in Thousands	Dec. 31, 2016USD ($)Claims	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2009USD ($)	Dec. 31, 2008USD ($)	Dec. 31, 2007USD ($)
Claims Development [Line Items]
Net reserve for losses and loss expenses	$ 3,692,009
Insurance | Agriculture
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	3,396,041
Cumulative paid	3,264,986
Net reserve for losses and loss expenses	131,055
Insurance | Agriculture | 2007
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Cumulative paid	0	0	0	0	0	0	0	0	0	0
IBNR reserves	$ 0
Cumulative number of reported claims | Claims	0
Insurance | Agriculture | 2008
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 313,834	313,834	313,834	313,938	313,814	313,800	313,296	318,709	333,380
Cumulative paid	313,834	313,834	313,834	313,859	313,722	313,708	313,196	310,235	239,498
IBNR reserves	$ 0
Cumulative number of reported claims | Claims	30,036
Insurance | Agriculture | 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 281,365	281,365	281,365	281,594	281,667	280,798	284,277	298,914
Cumulative paid	281,365	281,365	281,365	281,058	280,991	280,468	281,996	178,206
IBNR reserves	$ 0
Cumulative number of reported claims | Claims	26,540
Insurance | Agriculture | 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 280,008	280,008	280,008	280,166	280,409	280,330	305,131
Cumulative paid	280,008	280,008	280,008	279,859	279,768	279,397	144,296
IBNR reserves	$ 0
Cumulative number of reported claims | Claims	18,331
Insurance | Agriculture | 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 507,847	507,847	507,930	508,424	509,531	520,388
Cumulative paid	507,847	507,847	507,918	507,790	506,905	461,335
IBNR reserves	$ 0
Cumulative number of reported claims | Claims	37,061
Insurance | Agriculture | 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 572,469	572,995	573,376	576,836	581,455
Cumulative paid	572,469	572,995	572,885	573,781	478,797
IBNR reserves	$ 0
Cumulative number of reported claims | Claims	38,297
Insurance | Agriculture | 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 562,826	562,122	563,158	566,483
Cumulative paid	561,652	562,075	562,046	438,034
IBNR reserves	$ 0
Cumulative number of reported claims | Claims	44,138
Insurance | Agriculture | 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 449,705	451,843	451,710
Cumulative paid	449,705	448,046	352,202
IBNR reserves	$ 0
Cumulative number of reported claims | Claims	53,886
Insurance | Agriculture | 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 227,634	241,501
Cumulative paid	222,212	122,696
IBNR reserves	$ 0
Cumulative number of reported claims | Claims	39,508
Insurance | Agriculture | 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 200,353
Cumulative paid	75,894
IBNR reserves	$ 20,453
Cumulative number of reported claims | Claims	29,353
Insurance | Casualty and other specialty
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 1,894,408
Cumulative paid	1,086,876
Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance	30,599
Adjustment for unallocated claim expenses	43,666
Net reserve for losses and loss expenses	881,797
Insurance | Casualty and other specialty | 2007
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	191,927	196,072	197,246	213,895	235,482	232,186	232,156	228,021	251,840	254,678
Cumulative paid	163,236	159,687	152,297	144,982	139,923	124,887	103,283	66,865	38,777	9,090
IBNR reserves	$ 20,274
Cumulative number of reported claims | Claims	988
Insurance | Casualty and other specialty | 2008
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 312,759	328,153	339,927	347,477	363,094	366,479	333,844	296,079	285,334
Cumulative paid	266,264	261,201	255,585	239,185	200,021	169,331	129,840	82,811	36,479
IBNR reserves	$ 35,706
Cumulative number of reported claims | Claims	1,602
Insurance | Casualty and other specialty | 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 206,077	218,900	230,594	234,983	237,101	237,368	240,235	198,689
Cumulative paid	168,351	160,903	150,241	139,011	103,922	83,210	50,815	15,098
IBNR reserves	$ 24,553
Cumulative number of reported claims | Claims	2,509
Insurance | Casualty and other specialty | 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 122,748	135,214	160,450	175,922	179,208	179,854	150,636
Cumulative paid	96,785	88,737	83,634	64,917	27,379	4,279	863
IBNR reserves	$ 19,995
Cumulative number of reported claims | Claims	2,738
Insurance | Casualty and other specialty | 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 186,588	201,355	226,274	222,470	169,803	151,344
Cumulative paid	97,285	91,817	54,598	30,074	14,468	3,279
IBNR reserves	$ 48,836
Cumulative number of reported claims | Claims	4,319
Insurance | Casualty and other specialty | 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 179,929	183,644	187,141	182,924	164,568
Cumulative paid	75,508	51,381	32,686	16,190	3,707
IBNR reserves	$ 73,724
Cumulative number of reported claims | Claims	6,268
Insurance | Casualty and other specialty | 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 230,081	205,041	165,853	153,377
Cumulative paid	119,524	89,771	15,581	3,145
IBNR reserves	$ 81,540
Cumulative number of reported claims | Claims	6,790
Insurance | Casualty and other specialty | 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 141,970	132,184	120,226
Cumulative paid	36,446	18,914	3,389
IBNR reserves	$ 84,031
Cumulative number of reported claims | Claims	7,969
Insurance | Casualty and other specialty | 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 156,771	145,828
Cumulative paid	49,196	18,426
IBNR reserves	$ 77,472
Cumulative number of reported claims | Claims	8,717
Insurance | Casualty and other specialty | 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 165,558
Cumulative paid	14,281
IBNR reserves	$ 137,608
Cumulative number of reported claims | Claims	5,305
Insurance | Professional lines
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 924,788
Cumulative paid	545,066
Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance	61
Adjustment for unallocated claim expenses	26,477
Net reserve for losses and loss expenses	406,260
Insurance | Professional lines | 2007
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	122,969	125,496	116,711	113,520	117,895	119,243	120,358	150,972	110,525	52,739
Cumulative paid	122,867	120,328	110,254	100,693	100,560	90,128	62,321	1,744	987	83
IBNR reserves	$ 47
Cumulative number of reported claims | Claims	232
Insurance | Professional lines | 2008
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 164,412	138,119	127,641	109,471	96,887	88,047	83,358	62,586	62,838
Cumulative paid	113,175	98,770	72,576	48,997	16,613	15,888	14,027	1,898	54
IBNR reserves	$ 3,932
Cumulative number of reported claims | Claims	379
Insurance | Professional lines | 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 93,803	92,165	99,973	109,441	106,597	104,421	118,432	100,914
Cumulative paid	80,201	77,628	73,072	56,126	38,000	32,193	8,755	1,045
IBNR reserves	$ 5,728
Cumulative number of reported claims | Claims	1,039
Insurance | Professional lines | 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 69,387	74,856	82,421	92,931	101,591	105,611	108,369
Cumulative paid	51,885	48,978	46,982	36,506	27,557	16,014	1,932
IBNR reserves	$ 9,860
Cumulative number of reported claims | Claims	1,594
Insurance | Professional lines | 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 105,619	98,989	79,988	99,466	98,353	102,012
Cumulative paid	85,003	71,782	33,639	21,266	11,766	2,367
IBNR reserves	$ 15,265
Cumulative number of reported claims | Claims	1,232
Insurance | Professional lines | 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 69,333	79,591	101,426	103,358	101,872
Cumulative paid	35,678	29,854	22,237	13,185	2,582
IBNR reserves	$ 18,080
Cumulative number of reported claims | Claims	1,233
Insurance | Professional lines | 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 61,499	70,564	79,732	78,988
Cumulative paid	26,783	21,289	13,807	2,193
IBNR reserves	$ 27,377
Cumulative number of reported claims | Claims	1,255
Insurance | Professional lines | 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 57,446	66,524	64,437
Cumulative paid	20,020	7,081	1,167
IBNR reserves	$ 29,232
Cumulative number of reported claims | Claims	2,599
Insurance | Professional lines | 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 72,559	74,823
Cumulative paid	7,130	1,243
IBNR reserves	$ 58,966
Cumulative number of reported claims | Claims	3,464
Insurance | Professional lines | 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 107,761
Cumulative paid	2,324
IBNR reserves	$ 99,005
Cumulative number of reported claims | Claims	3,814
Insurance | Property, marine/energy and aviation
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 1,029,879
Cumulative paid	763,341
Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance	3
Adjustment for unallocated claim expenses	7,855
Net reserve for losses and loss expenses	274,396
Insurance | Property, marine/energy and aviation | 2007
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	32,680	34,083	33,741	33,206	28,925	29,071	28,766	25,714	32,772	45,128
Cumulative paid	32,671	34,084	33,546	32,561	23,780	23,482	22,614	21,987	19,644	$ 10,626
IBNR reserves	$ 0
Cumulative number of reported claims | Claims	201
Insurance | Property, marine/energy and aviation | 2008
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 77,373	78,178	78,176	80,158	84,093	74,111	84,425	104,626	113,427
Cumulative paid	77,239	77,910	77,234	75,042	75,187	64,434	62,922	57,685	$ 40,140
IBNR reserves	$ 13
Cumulative number of reported claims | Claims	459
Insurance | Property, marine/energy and aviation | 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 19,341	19,780	19,423	19,933	21,225	23,651	48,196	60,589
Cumulative paid	19,261	19,407	19,075	18,887	18,657	18,120	16,967	$ 11,014
IBNR reserves	$ 33
Cumulative number of reported claims | Claims	568
Insurance | Property, marine/energy and aviation | 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 43,240	42,202	41,703	42,918	48,033	54,986	93,741
Cumulative paid	41,802	40,782	38,880	36,306	33,938	29,150	$ 11,680
IBNR reserves	$ 992
Cumulative number of reported claims | Claims	1,423
Insurance | Property, marine/energy and aviation | 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 133,297	127,840	124,243	125,588	139,932	163,234
Cumulative paid	123,496	117,337	103,301	82,967	63,710	$ 17,871
IBNR reserves	$ 256
Cumulative number of reported claims | Claims	2,486
Insurance | Property, marine/energy and aviation | 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 121,873	121,281	123,134	137,329	172,535
Cumulative paid	108,983	102,447	87,216	79,533	$ 18,709
IBNR reserves	$ 405
Cumulative number of reported claims | Claims	2,704
Insurance | Property, marine/energy and aviation | 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 80,971	85,794	101,878	115,600
Cumulative paid	71,423	66,851	57,243	$ 20,929
IBNR reserves	$ 3,933
Cumulative number of reported claims | Claims	3,145
Insurance | Property, marine/energy and aviation | 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 102,002	114,243	136,748
Cumulative paid	79,321	60,418	$ 26,491
IBNR reserves	$ 7,588
Cumulative number of reported claims | Claims	4,405
Insurance | Property, marine/energy and aviation | 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 184,867	183,192
Cumulative paid	131,697	$ 52,121
IBNR reserves	$ 18,890
Cumulative number of reported claims | Claims	6,281
Insurance | Property, marine/energy and aviation | 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 234,235
Cumulative paid	77,448
IBNR reserves	$ 72,271
Cumulative number of reported claims | Claims	6,600

Reserve For Losses And Loss E83

Reserve For Losses And Loss Expenses (Claims Development - Reinsurance) (Details) $ in Thousands	Dec. 31, 2016USD ($)Claims	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2009USD ($)	Dec. 31, 2008USD ($)	Dec. 31, 2007USD ($)
Claims Development [Line Items]
Net reserve for losses and loss expenses	$ 3,692,009
Reinsurance | Catastrophe
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	1,980,477
Cumulative paid	1,813,145
Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance	91
Adjustment for unallocated claim expenses	3,002
Net reserve for losses and loss expenses	170,425
Reinsurance | Catastrophe | 2007
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	102,929	$ 97,851	$ 90,379	$ 86,273	$ 88,252	$ 91,502	$ 102,855	$ 104,527	$ 126,561	$ 168,640
Cumulative paid	102,497	97,279	88,684	80,852	82,285	83,511	91,214	87,267	85,271	31,590
IBNR reserves	$ 153
Cumulative number of reported claims | Claims	192
Reinsurance | Catastrophe | 2008
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 381,551	384,864	382,068	382,382	384,117	392,668	389,111	378,838	405,190
Cumulative paid	380,409	382,431	380,366	378,322	375,455	353,658	316,023	255,721	154,382
IBNR reserves	$ 317
Cumulative number of reported claims | Claims	336
Reinsurance | Catastrophe | 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 60,788	58,910	56,944	55,229	55,933	59,051	74,817	102,411
Cumulative paid	59,865	57,551	54,189	51,013	49,847	48,440	45,763	26,869
IBNR reserves	$ 559
Cumulative number of reported claims | Claims	204
Reinsurance | Catastrophe | 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 224,323	237,677	231,531	226,208	226,060	234,576	272,094
Cumulative paid	208,329	207,716	193,340	173,341	152,264	124,322	58,556
IBNR reserves	$ 1,394
Cumulative number of reported claims | Claims	265
Reinsurance | Catastrophe | 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 624,448	612,274	603,680	589,614	591,965	622,350
Cumulative paid	615,504	593,831	561,864	495,351	385,304	230,619
IBNR reserves	$ 4,640
Cumulative number of reported claims | Claims	574
Reinsurance | Catastrophe | 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 151,003	154,240	163,109	180,145	245,011
Cumulative paid	136,862	134,288	126,802	105,745	56,614
IBNR reserves	$ 3,884
Cumulative number of reported claims | Claims	345
Reinsurance | Catastrophe | 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 124,311	127,984	129,469	157,097
Cumulative paid	116,996	106,983	83,259	34,236
IBNR reserves	$ 1,454
Cumulative number of reported claims | Claims	315
Reinsurance | Catastrophe | 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 126,512	126,822	141,173
Cumulative paid	117,040	107,546	49,337
IBNR reserves	$ 3,156
Cumulative number of reported claims | Claims	229
Reinsurance | Catastrophe | 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 47,255	60,465
Cumulative paid	31,850	20,084
IBNR reserves	$ 4,057
Cumulative number of reported claims | Claims	224
Reinsurance | Catastrophe | 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 137,357
Cumulative paid	43,793
IBNR reserves	$ 27,654
Cumulative number of reported claims | Claims	216
Reinsurance | Property
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 1,852,608
Cumulative paid	1,542,984
Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance	4,954
Adjustment for unallocated claim expenses	4,301
Net reserve for losses and loss expenses	318,879
Reinsurance | Property | 2007
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	117,706	121,902	121,653	119,773	115,947	116,552	120,598	127,294	137,474	123,502
Cumulative paid	116,680	120,881	119,203	116,499	112,559	111,155	111,825	103,059	71,828	23,678
IBNR reserves	$ 2
Cumulative number of reported claims | Claims	309
Reinsurance | Property | 2008
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 122,943	125,622	126,991	126,887	124,861	123,162	133,022	151,764	173,437
Cumulative paid	121,472	123,954	122,512	118,745	110,039	107,291	104,279	79,457	30,553
IBNR reserves	$ 3
Cumulative number of reported claims | Claims	612
Reinsurance | Property | 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 111,782	115,213	115,111	114,342	114,137	116,114	123,151	151,371
Cumulative paid	107,609	109,796	107,021	103,688	97,377	89,940	71,123	27,690
IBNR reserves	$ 114
Cumulative number of reported claims | Claims	991
Reinsurance | Property | 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 174,952	188,304	188,516	186,817	190,322	216,726	221,480
Cumulative paid	170,367	180,555	175,919	163,173	141,348	117,260	49,442
IBNR reserves	$ 419
Cumulative number of reported claims | Claims	1,126
Reinsurance | Property | 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 335,228	305,567	312,278	312,365	334,865	344,015
Cumulative paid	326,570	291,961	286,065	254,657	172,679	76,880
IBNR reserves	$ 2,089
Cumulative number of reported claims | Claims	942
Reinsurance | Property | 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 244,651	240,070	240,928	259,753	314,924
Cumulative paid	230,684	214,711	192,022	146,671	53,488
IBNR reserves	$ 2,224
Cumulative number of reported claims | Claims	813
Reinsurance | Property | 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 199,195	217,661	239,844	255,632
Cumulative paid	176,721	173,888	138,841	55,668
IBNR reserves	$ 5,650
Cumulative number of reported claims | Claims	1,017
Reinsurance | Property | 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 197,761	211,888	211,769
Cumulative paid	158,766	134,663	51,635
IBNR reserves	$ 11,702
Cumulative number of reported claims | Claims	1,060
Reinsurance | Property | 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 181,761	184,586
Cumulative paid	100,328	37,685
IBNR reserves	$ 16,927
Cumulative number of reported claims | Claims	880
Reinsurance | Property | 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 166,629
Cumulative paid	33,787
IBNR reserves	$ 55,289
Cumulative number of reported claims | Claims	542
Reinsurance | Casualty
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 1,397,900
Cumulative paid	783,362
Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance	106,483
Adjustment for unallocated claim expenses	10,637
Net reserve for losses and loss expenses	731,658
Reinsurance | Casualty | 2007
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	112,366	110,369	111,664	112,945	114,484	115,024	120,815	116,095	116,074	108,468
Cumulative paid	87,170	77,378	73,518	64,711	57,254	48,519	35,928	23,890	13,399	3,009
IBNR reserves	$ 13,382
Cumulative number of reported claims | Claims	549
Reinsurance | Casualty | 2008
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 93,732	97,260	98,504	101,613	107,336	114,790	116,204	118,736	112,680
Cumulative paid	75,906	72,592	67,856	58,419	51,831	43,923	30,528	17,338	8,475
IBNR reserves	$ 9,538
Cumulative number of reported claims | Claims	406
Reinsurance | Casualty | 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 114,901	115,317	121,969	126,505	127,972	124,218	126,969	116,515
Cumulative paid	83,892	76,463	70,558	61,615	51,576	34,770	21,841	7,367
IBNR reserves	$ 20,438
Cumulative number of reported claims | Claims	433
Reinsurance | Casualty | 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 159,409	160,142	172,699	170,938	176,073	179,891	186,667
Cumulative paid	114,875	104,037	92,382	75,290	56,997	34,469	14,826
IBNR reserves	$ 27,794
Cumulative number of reported claims | Claims	506
Reinsurance | Casualty | 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 196,946	195,094	204,187	197,138	199,035	198,159
Cumulative paid	141,449	116,519	104,394	77,748	50,998	28,035
IBNR reserves	$ 35,929
Cumulative number of reported claims | Claims	604
Reinsurance | Casualty | 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 174,625	183,512	193,164	191,436	195,983
Cumulative paid	105,209	92,072	75,456	54,457	30,667
IBNR reserves	$ 42,134
Cumulative number of reported claims | Claims	701
Reinsurance | Casualty | 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 163,986	170,144	172,604	178,401
Cumulative paid	71,677	56,564	35,808	18,577
IBNR reserves	$ 62,188
Cumulative number of reported claims | Claims	842
Reinsurance | Casualty | 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 119,143	120,521	125,515
Cumulative paid	49,951	33,215	10,390
IBNR reserves	$ 45,271
Cumulative number of reported claims | Claims	615
Reinsurance | Casualty | 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 119,529	119,276
Cumulative paid	34,396	15,817
IBNR reserves	$ 58,182
Cumulative number of reported claims | Claims	250
Reinsurance | Casualty | 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 143,263
Cumulative paid	18,837
IBNR reserves	$ 106,858
Cumulative number of reported claims | Claims	127
Reinsurance | Professional lines
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 634,368
Cumulative paid	221,349
Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance	5,540
Adjustment for unallocated claim expenses	6,164
Net reserve for losses and loss expenses	424,723
Reinsurance | Professional lines | 2007
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	37,980	41,989	42,115	43,261	41,037	41,956	43,988	49,539	51,283	46,031
Cumulative paid	32,771	33,144	30,796	28,121	21,259	16,764	10,694	5,649	2,310	144
IBNR reserves	$ 1,539
Cumulative number of reported claims | Claims	310
Reinsurance | Professional lines | 2008
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 39,059	41,599	42,863	44,526	47,084	44,672	47,154	50,276	41,797
Cumulative paid	33,434	32,873	30,169	26,811	22,496	12,752	6,200	2,156	341
IBNR reserves	$ 1,171
Cumulative number of reported claims | Claims	262
Reinsurance | Professional lines | 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 38,720	36,474	36,560	35,771	40,763	41,681	43,003	41,430
Cumulative paid	32,329	27,039	23,469	19,184	15,666	7,963	3,330	1,033
IBNR reserves	$ 2,098
Cumulative number of reported claims | Claims	204
Reinsurance | Professional lines | 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 45,024	46,661	53,825	62,185	67,335	58,567	58,153
Cumulative paid	36,181	36,100	31,313	24,511	14,481	7,348	2,249
IBNR reserves	$ 3,733
Cumulative number of reported claims | Claims	110
Reinsurance | Professional lines | 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 31,390	36,691	44,921	55,286	56,535	55,812
Cumulative paid	22,142	20,124	15,168	9,405	4,943	1,685
IBNR reserves	$ 4,828
Cumulative number of reported claims | Claims	57
Reinsurance | Professional lines | 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 30,576	36,707	43,426	42,443	43,519
Cumulative paid	13,757	9,147	4,204	1,929	965
IBNR reserves	$ 5,803
Cumulative number of reported claims | Claims	81
Reinsurance | Professional lines | 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 41,403	45,382	49,513	48,933
Cumulative paid	11,636	6,694	2,561	997
IBNR reserves	$ 21,619
Cumulative number of reported claims | Claims	48
Reinsurance | Professional lines | 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 90,713	88,915	91,943
Cumulative paid	22,822	6,446	1,149
IBNR reserves	$ 50,367
Cumulative number of reported claims | Claims	62
Reinsurance | Professional lines | 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 130,832	130,595
Cumulative paid	14,357	2,941
IBNR reserves	$ 99,261
Cumulative number of reported claims | Claims	55
Reinsurance | Professional lines | 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 148,671
Cumulative paid	1,920
IBNR reserves	$ 139,857
Cumulative number of reported claims | Claims	10
Reinsurance | Specialty
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 1,052,826
Cumulative paid	730,394
Reserve for losses and loss expenses from accident year 2006 and prior, net of reinsurance	24,265
Adjustment for unallocated claim expenses	6,119
Net reserve for losses and loss expenses	352,816
Reinsurance | Specialty | 2007
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	174,205	183,044	185,743	187,949	187,961	189,577	193,084	197,905	202,655	229,505
Cumulative paid	169,673	177,082	175,948	174,059	169,797	160,113	153,622	143,800	123,632	$ 16,023
IBNR reserves	$ 435
Cumulative number of reported claims | Claims	288
Reinsurance | Specialty | 2008
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 67,604	73,745	75,348	77,556	79,052	79,903	92,039	94,050	125,389
Cumulative paid	61,384	65,005	64,489	61,915	58,971	52,461	47,410	38,261	$ 15,525
IBNR reserves	$ 3,549
Cumulative number of reported claims | Claims	195
Reinsurance | Specialty | 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 62,501	62,834	65,333	67,605	69,691	73,387	81,269	98,431
Cumulative paid	55,068	52,635	52,481	47,556	43,804	39,439	33,142	$ 13,286
IBNR reserves	$ 4,414
Cumulative number of reported claims | Claims	170
Reinsurance | Specialty | 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 82,937	84,817	85,252	86,949	97,718	107,630	123,741
Cumulative paid	74,797	72,072	68,915	64,199	57,822	48,043	$ 15,110
IBNR reserves	$ 1,856
Cumulative number of reported claims | Claims	218
Reinsurance | Specialty | 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 82,014	82,984	82,514	86,832	100,639	111,517
Cumulative paid	75,760	73,730	68,869	61,019	44,494	$ 22,755
IBNR reserves	$ 2,565
Cumulative number of reported claims | Claims	274
Reinsurance | Specialty | 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 85,852	92,162	99,700	111,813	135,448
Cumulative paid	74,517	72,510	64,242	53,695	$ 29,756
IBNR reserves	$ 5,174
Cumulative number of reported claims | Claims	294
Reinsurance | Specialty | 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 83,806	92,119	93,335	103,014
Cumulative paid	62,458	52,015	37,621	$ 14,696
IBNR reserves	$ 9,865
Cumulative number of reported claims | Claims	329
Reinsurance | Specialty | 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 108,392	116,642	120,335
Cumulative paid	66,813	49,847	$ 23,579
IBNR reserves	$ 19,693
Cumulative number of reported claims | Claims	342
Reinsurance | Specialty | 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 149,473	150,288
Cumulative paid	70,659	$ 18,994
IBNR reserves	$ 35,118
Cumulative number of reported claims | Claims	318
Reinsurance | Specialty | 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 156,042
Cumulative paid	19,265
IBNR reserves	$ 111,660
Cumulative number of reported claims | Claims	134

Reserve For Losses And Loss E84

Reserve For Losses And Loss Expenses (Reconciliation of Claims Development) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net reserve for losses and loss expenses	$ 3,692,009
Reinsurance recoverable on unpaid losses	1,213,129	$ 907,944	$ 670,795	$ 593,755
Reserve for losses and loss expenses	4,905,138	4,510,415	3,846,859	$ 4,002,259
Insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Reserve for losses and loss expenses	2,798,989	2,493,894	2,123,772
Insurance | Agriculture
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net reserve for losses and loss expenses	131,055
Reinsurance recoverable on unpaid losses	116,832
Reserve for losses and loss expenses	247,887
Insurance | Casualty and other specialty
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net reserve for losses and loss expenses	881,797
Reinsurance recoverable on unpaid losses	490,447
Reserve for losses and loss expenses	1,372,244
Insurance | Professional lines
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net reserve for losses and loss expenses	406,260
Reinsurance recoverable on unpaid losses	305,114
Reserve for losses and loss expenses	711,374
Insurance | Property, marine/energy and aviation
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net reserve for losses and loss expenses	274,396
Reinsurance recoverable on unpaid losses	193,088
Reserve for losses and loss expenses	467,484
Reinsurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Reserve for losses and loss expenses	2,106,149	$ 2,016,521	$ 1,723,087
Reinsurance | Catastrophe
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net reserve for losses and loss expenses	170,425
Reinsurance recoverable on unpaid losses	39,419
Reserve for losses and loss expenses	209,844
Reinsurance | Property
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net reserve for losses and loss expenses	318,879
Reinsurance recoverable on unpaid losses	1,466
Reserve for losses and loss expenses	320,345
Reinsurance | Casualty
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net reserve for losses and loss expenses	731,658
Reinsurance recoverable on unpaid losses	1,175
Reserve for losses and loss expenses	732,833
Reinsurance | Professional lines
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net reserve for losses and loss expenses	424,723
Reinsurance recoverable on unpaid losses	449
Reserve for losses and loss expenses	425,172
Reinsurance | Specialty
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net reserve for losses and loss expenses	352,816
Reinsurance recoverable on unpaid losses	65,139
Reserve for losses and loss expenses	$ 417,955

Reserve For Losses And Loss E85

Reserve For Losses And Loss Expenses (Claims Duration) (Details)	Dec. 31, 2016
Insurance | Agriculture
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	73.30%
Year 2	24.10%
Year 3	0.10%
Year 4	0.30%
Year 5	0.00%
Year 6	0.00%
Year 7	0.00%
Year 8	0.00%
Year 9	0.00%
Year 10	0.00%
Insurance | Casualty and other specialty
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	5.50%
Year 2	11.30%
Year 3	15.50%
Year 4	15.10%
Year 5	12.80%
Year 6	7.10%
Year 7	4.50%
Year 8	2.70%
Year 9	3.70%
Year 10	1.40%
Insurance | Professional lines
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	1.50%
Year 2	7.80%
Year 3	11.00%
Year 4	14.30%
Year 5	15.00%
Year 6	14.40%
Year 7	10.30%
Year 8	8.90%
Year 9	8.30%
Year 10	7.20%
Insurance | Property, marine/energy and aviation
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	24.40%
Year 2	39.30%
Year 3	18.00%
Year 4	9.90%
Year 5	4.30%
Year 6	2.10%
Year 7	3.20%
Year 8	0.40%
Year 9	1.10%
Year 10	0.20%
Reinsurance | Catastrophe
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	32.40%
Year 2	36.10%
Year 3	15.40%
Year 4	7.60%
Year 5	3.40%
Year 6	1.70%
Year 7	0.20%
Year 8	0.30%
Year 9	1.30%
Year 10	1.00%
Reinsurance | Property
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	24.10%
Year 2	39.40%
Year 3	19.50%
Year 4	6.50%
Year 5	3.50%
Year 6	2.70%
Year 7	0.50%
Year 8	0.90%
Year 9	0.90%
Year 10	0.30%
Reinsurance | Casualty
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	9.20%
Year 2	12.60%
Year 3	12.70%
Year 4	11.90%
Year 5	9.90%
Year 6	8.20%
Year 7	6.30%
Year 8	5.50%
Year 9	4.40%
Year 10	3.20%
Reinsurance | Professional lines
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	1.90%
Year 2	6.70%
Year 3	12.10%
Year 4	18.50%
Year 5	16.90%
Year 6	12.20%
Year 7	8.20%
Year 8	6.40%
Year 9	4.30%
Year 10	3.30%
Reinsurance | Specialty
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	13.90%
Year 2	37.70%
Year 3	20.60%
Year 4	7.00%
Year 5	7.60%
Year 6	4.60%
Year 7	2.20%
Year 8	3.10%
Year 9	0.60%
Year 10	0.00%

Reinsurance (Narrative) (Detail

Reinsurance (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reinsurance Disclosures [Abstract]
Ceded losses	$ 824.3	$ 833.7	$ 575.7

Reinsurance (Effects Of Reinsur

Reinsurance (Effects Of Reinsurance On Premiums Earned And Written) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reinsurance Disclosures [Abstract]
Direct premiums earned									$ 2,336,314	$ 1,938,830	$ 1,521,648
Assumed premiums earned									1,635,379	1,331,831	1,132,370
Ceded premiums earned									(1,608,033)	(1,292,208)	(790,040)
Net premiums earned	$ 600,705	$ 610,156	$ 599,608	$ 553,191	$ 573,456	$ 557,003	$ 458,135	$ 389,859	2,363,660	1,978,453	1,863,978
Direct premiums written									2,570,494	2,085,901	1,716,128
Assumed premiums written									1,631,676	1,234,960	1,177,948
Ceded premiums written									(1,832,235)	(1,370,391)	(959,870)
Net premiums written									$ 2,369,935	$ 1,950,470	$ 1,934,206

Reinsurance (Losses Recoverable

Reinsurance (Losses Recoverable On Paid And Unpaid Losses By Rating) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Ceded Credit Risk [Line Items]
Reinsurance Recoverables	$ 1,486,918	$ 1,195,970
Collateralized [Member]
Ceded Credit Risk [Line Items]
Reinsurance Recoverables	493,300	321,500
U.S. Government sponsored program
Ceded Credit Risk [Line Items]
Reinsurance Recoverables	141,443	234,596
A plus and above
Ceded Credit Risk [Line Items]
Reinsurance Recoverables	889,814	458,255
A
Ceded Credit Risk [Line Items]
Reinsurance Recoverables	397,691	476,184
A-
Ceded Credit Risk [Line Items]
Reinsurance Recoverables	5,805	7,060
Not rated
Ceded Credit Risk [Line Items]
Reinsurance Recoverables	$ 52,165	$ 19,875

Debt And Financing Arrangemen89

Debt And Financing Arrangements (Credit Facility) (Details) - USD ($) $ in Thousands	Mar. 23, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Apr. 19, 2012
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 450,000				$ 700,000
Amount outstanding under credit facility		$ 0	$ 0
Amount of letters of credit outstanding		$ 222,300	341,600
Line Of Credit Facility Used Capacity Commitment Fee Percentage		0.40%
Line of Credit Facility, Commitment Fee Percentage		0.125%
Aggregate interest payments		$ 42,700	40,500	$ 40,400
High
Line of Credit Facility [Line Items]
Leverage ratio		35.00%
Credit Facility [Member]
Line of Credit Facility [Line Items]
Term of facility	5 years
Amount of letters of credit outstanding		$ 199,800	329,900
Increase to credit facility		100,000
LOC Agreements [Member]
Line of Credit Facility [Line Items]
Amount of letters of credit outstanding		$ 22,500	$ 11,700
LOC Agreements [Member] | Low
Line of Credit Facility [Line Items]
Line Of Credit Facility Used Capacity Commitment Fee Percentage		0.30%
LOC Agreements [Member] | High
Line of Credit Facility [Line Items]
Line Of Credit Facility Used Capacity Commitment Fee Percentage		0.45%
LIBOR | Trust Preferred Securities [Member]
Line of Credit Facility [Line Items]
Interest rate spread on LIBOR rate		3.80%

Debt And Financing Arrangemen90

Debt And Financing Arrangements (Senior Notes and Trust Preferred Securities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Aggregate interest payments	$ 42.7	$ 40.5	$ 40.4
LIBOR swap
Debt Instrument [Line Items]
Stated interest rate	4.905%
Term of LIBOR swap	5 years
Seven Percent Senior Notes [Member]
Debt Instrument [Line Items]
Principal amount	$ 335
Stated interest rate	7.00%
Six Point One Five Percent Senior Notes [Member]
Debt Instrument [Line Items]
Principal amount	$ 200
Stated interest rate	6.15%
Four Point Seven Percent Senior Notes [Member]
Debt Instrument [Line Items]
Principal amount	$ 300
Stated interest rate	4.70%
Trust Preferred Securities [Member]
Debt Instrument [Line Items]
Principal amount	$ 100
Debt Instrument, Description of Variable Rate Basis	3-month
Debt Instrument, Redemption Price, Percentage	100.00%

Debt And Financing Arrangemen91

Debt And Financing Arrangements (Credit Agreements) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	May 06, 2016	Mar. 23, 2016	Dec. 31, 2015	Apr. 19, 2012
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	$ 222,300			$ 341,600
Maximum borrowing capacity			$ 450,000		$ 700,000
Blue Capital Reinsurance Holdings [Member]
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	0
Maximum borrowing capacity		$ 20,000
Blue Capital Global Reinsurance Fund [Member]
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	$ 0
Maximum borrowing capacity		$ 20,000
LIBOR | Blue Capital Reinsurance Holdings [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%
LIBOR | Blue Capital Global Reinsurance Fund [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%

Derivatives (Narrative) (Detail

Derivatives (Narrative) (Details) - Cash Flow Hedging [Member] $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Senior Notes, stated interest rate	7.00%
Notional amount	$ 125
Percentage of protection	50.00%
U.S. treasury benchmark in years	30 years
Payment for interest rate lock derivative	$ 2.7

Derivatives (Schedule Of The Fa

Derivatives (Schedule Of The Fair Values And The Related Notional Values Of Derivatives Included In The Company's Consolidated Balance Sheet) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Derivatives recorded in other assets, fair value	$ 166,716	$ 68,892
Derivatives recorded in other liabilities, fair value	84,069	46,088
Net derivative asset	82,647	22,804
Derivative assets traded under master netting agreements	166,700	68,900
Derivative liabilities traded under master netting agreements	84,100	46,100
Securities for Reverse Repurchase Agreements	$ 0	30,000
Low
Derivatives, Fair Value [Line Items]
Required Collateral Percentage	102.00%
Foreign exchange forward contracts
Derivatives, Fair Value [Line Items]
Derivatives recorded in other assets, fair value	$ 629	425
Derivatives recorded in other liabilities, fair value	1,204	372
Derivative recorded in other assets, notional principal amount	34,630	38,818
Derivative recorded in other liabilities, notional principal amount	32,080	30,400
Credit default swaps
Derivatives, Fair Value [Line Items]
Derivatives recorded in other assets, fair value	266	36
Derivatives recorded in other liabilities, fair value	21	276
Derivative recorded in other assets, notional principal amount	5,450	4,225
Derivative recorded in other liabilities, notional principal amount	$ 2,744	7,800
Credit default swaps | High
Derivatives, Fair Value [Line Items]
Original term of credit default swap, in years	5 years
Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivatives recorded in other assets, fair value	$ 374	0
Derivatives recorded in other liabilities, fair value	59	7
Derivative recorded in other assets, notional principal amount	7,000	0
Derivative recorded in other liabilities, notional principal amount	1,100	42,000
Interest rate swaptions
Derivatives, Fair Value [Line Items]
Derivatives recorded in other liabilities, fair value	34	0
Derivative recorded in other liabilities, notional principal amount	5,400	0
Interest rate futures
Derivatives, Fair Value [Line Items]
Derivatives recorded in other liabilities, fair value	0	8
Derivative recorded in other liabilities, notional principal amount	0	54,488
ILWs
Derivatives, Fair Value [Line Items]
Derivatives recorded in other assets, fair value	1,010	0
Derivatives recorded in other liabilities, fair value	184	259
Derivative recorded in other assets, notional principal amount	20,000	0
Derivative recorded in other liabilities, notional principal amount	14,209	19,500
LIBOR swap
Derivatives, Fair Value [Line Items]
Derivatives recorded in other liabilities, fair value	27	233
Derivative recorded in other liabilities, notional principal amount	$ 100,000	100,000
Term of LIBOR swap	5 years
Stated interest rate	4.905%
TBAs
Derivatives, Fair Value [Line Items]
Derivatives recorded in other assets, fair value	$ 121,402	26,924
Derivatives recorded in other liabilities, fair value	50,704	0
Derivative recorded in other assets, notional principal amount	120,300	25,700
Derivative recorded in other liabilities, notional principal amount	50,400	0
Loss development cover
Derivatives, Fair Value [Line Items]
Derivatives recorded in other liabilities, fair value	2,818	2,904
Derivative recorded in other liabilities, notional principal amount	24,451	22,322
Energy and weather contracts
Derivatives, Fair Value [Line Items]
Derivatives recorded in other assets, fair value	43,035	41,507
Derivatives recorded in other liabilities, fair value	29,018	42,029
Derivative recorded in other assets, notional principal amount	101,436	70,388
Derivative recorded in other liabilities, notional principal amount	$ 162,900	$ 148,325

Derivatives (Schedule Of The Ga

Derivatives (Schedule Of The Gains And Losses On Derivative Instruments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative [Line Items]
Total (losses) gains included in net realized and unrealized (losses) gains	$ (2,180)	$ (328)	$ 327
Total gain (loss) included in other underwriting loss	2,706	862	(315)
Total gains from derivatives	1,042	2,629	1,892
Foreign exchange forward contracts
Derivative [Line Items]
Total gain included in net foreign exchange (gains) losses from foreign exchange forward contracts	516	2,095	1,880
Interest rate futures
Derivative [Line Items]
Total (losses) gains included in net realized and unrealized (losses) gains	(160)	79	121
Credit default swaps
Derivative [Line Items]
Total (losses) gains included in net realized and unrealized (losses) gains	7	(50)	30
Interest rate swaps
Derivative [Line Items]
Total (losses) gains included in net realized and unrealized (losses) gains	124	(915)	(4,239)
Interest rate swaptions
Derivative [Line Items]
Total (losses) gains included in net realized and unrealized (losses) gains	(20)	56	477
ILWs
Derivative [Line Items]
Total (losses) gains included in net realized and unrealized (losses) gains	(1,675)	(326)	0
LIBOR swap
Derivative [Line Items]
Total (losses) gains included in net realized and unrealized (losses) gains	206	332	0
TBAs
Derivative [Line Items]
Total (losses) gains included in net realized and unrealized (losses) gains	(662)	496	3,938
Energy and weather contracts
Derivative [Line Items]
Total gain (loss) included in other underwriting loss	4,835	2,281	(315)
Loss development cover
Derivative [Line Items]
Total gain (loss) included in other underwriting loss	$ (2,129)	$ (1,419)	$ 0

Segment Reporting (Summary Of T

Segment Reporting (Summary Of The Segment Revenues, Results And Reserve For Losses And Loss Expenses And Carrying Value Of Goodwill) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Gross premiums written										$ 4,202,170	$ 3,320,861	$ 2,894,076
Ceded premiums written										(1,832,235)	(1,370,391)	(959,870)
Net premiums written										2,369,935	1,950,470	1,934,206
Net premiums earned		$ 600,705	$ 610,156	$ 599,608	$ 553,191	$ 573,456	$ 557,003	$ 458,135	$ 389,859	2,363,660	1,978,453	1,863,978
Other underwriting loss										(909)	(3,694)	(5,786)
Total revenue										2,362,751	1,974,759	1,858,192
Net losses and loss expenses		370,150	331,462	376,112	243,328	242,057	263,993	239,122	171,936	1,321,052	917,108	970,162
Acquisition expenses										460,483	347,885	319,513
General and administrative expenses										248,146	259,791	247,387
Total expenses										2,029,681	1,524,784	1,537,062
Underwriting income										333,070	449,975	321,130
Net investment income		59,196	62,236	43,977	11,181	23,180	16,533	32,252	41,861	176,590	113,826	131,543
Corporate expenses										(51,706)	(114,429)	(66,200)
Net foreign exchange gains		11,628	18,576	32,751	11,729	2,190	(8,621)	(12,981)	(7,552)	74,684	(26,964)	(3,839)
Net realized and unrealized (losses) gains		(45,958)	13,405	6,347	13,787	(20,238)	5,029	9,680	18,189	(12,419)	12,660	14,283
Net impairment losses recognized in earnings		(122)	$ (183)	$ (9,841)	$ (623)	(2,604)	$ (38)	$ (424)	$ (649)	(10,769)	(3,715)	(625)
Amortization of intangibles										(84,624)	(30,620)	(6,484)
Interest expense										(43,860)	(41,260)	(40,968)
Income before income taxes										$ 380,966	$ 359,473	$ 348,840
Net loss ratio										55.90%	46.40%	52.10%
Acquisition expense ratio										19.50%	17.60%	17.10%
General and administrative expense ratio	[1]									12.70%	18.90%	16.80%
Combined ratio										88.10%	82.90%	86.00%
Reserve for losses and loss expenses		4,905,138				4,510,415				$ 4,905,138	$ 4,510,415	$ 3,846,859	$ 4,002,259
Goodwill		175,482				176,455				175,482	176,455	91,238
Insurance
Segment Reporting Information [Line Items]
Gross premiums written										2,570,494	2,085,901	1,716,128
Ceded premiums written										(1,514,240)	(1,205,528)	(855,722)
Net premiums written										1,056,254	880,373	860,406
Net premiums earned										1,009,375	824,552	833,912
Other underwriting loss										0	0	0
Total revenue										1,009,375	824,552	833,912
Net losses and loss expenses										684,178	500,867	594,561
Acquisition expenses										149,763	80,252	65,368
General and administrative expenses										140,742	140,012	148,475
Total expenses										974,683	721,131	808,404
Underwriting income										$ 34,692	$ 103,421	$ 25,508
Net loss ratio										67.90%	60.80%	71.40%
Acquisition expense ratio										14.80%	9.70%	7.80%
General and administrative expense ratio	[1]									13.90%	17.00%	17.70%
Combined ratio										96.60%	87.50%	96.90%
Reserve for losses and loss expenses		2,798,989				2,493,894				$ 2,798,989	$ 2,493,894	$ 2,123,772
Goodwill		83,550				84,525				83,550	84,525	47,925
Reinsurance
Segment Reporting Information [Line Items]
Gross premiums written										1,631,676	1,234,960	1,177,948
Ceded premiums written										(317,995)	(164,863)	(104,148)
Net premiums written										1,313,681	1,070,097	1,073,800
Net premiums earned										1,354,285	1,153,901	1,030,066
Other underwriting loss										(909)	(3,694)	(5,786)
Total revenue										1,353,376	1,150,207	1,024,280
Net losses and loss expenses										636,874	416,241	375,601
Acquisition expenses										310,720	267,633	254,145
General and administrative expenses										107,404	119,779	98,912
Total expenses										1,054,998	803,653	728,658
Underwriting income										$ 298,378	$ 346,554	$ 295,622
Net loss ratio										47.10%	36.00%	36.40%
Acquisition expense ratio										22.90%	23.20%	24.70%
General and administrative expense ratio	[1]									7.90%	10.40%	9.60%
Combined ratio										77.90%	69.60%	70.70%
Reserve for losses and loss expenses		2,106,149				2,016,521				$ 2,106,149	$ 2,016,521	$ 1,723,087
Goodwill		$ 91,932				$ 91,930				$ 91,932	$ 91,930	$ 43,313
[1]	Total general and administrative expense ratio includes general and administrative expenses and corporate expenses.

Segment Reporting (Schedule Of

Segment Reporting (Schedule Of Gross Premiums Written By Line Of Business) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue, Major Customer [Line Items]
Gross premiums written	$ 4,202,170	$ 3,320,861	$ 2,894,076
Agriculture
Revenue, Major Customer [Line Items]
Gross premiums written	760,877	840,445	866,025
Casualty and other specialty
Revenue, Major Customer [Line Items]
Gross premiums written	657,558	514,203	396,113
Professional lines
Revenue, Major Customer [Line Items]
Gross premiums written	461,552	344,482	263,538
Property, marine/energy and aviation
Revenue, Major Customer [Line Items]
Gross premiums written	690,507	386,771	190,452
Catastrophe
Revenue, Major Customer [Line Items]
Gross premiums written	506,300	311,914	343,213
Property
Revenue, Major Customer [Line Items]
Gross premiums written	250,447	209,392	287,326
Casualty
Revenue, Major Customer [Line Items]
Gross premiums written	245,092	176,506	159,533
Professional lines
Revenue, Major Customer [Line Items]
Gross premiums written	256,337	248,610	174,656
Specialty
Revenue, Major Customer [Line Items]
Gross premiums written	373,500	288,538	213,220
Insurance
Revenue, Major Customer [Line Items]
Gross premiums written	2,570,494	2,085,901	1,716,128
Reinsurance
Revenue, Major Customer [Line Items]
Gross premiums written	$ 1,631,676	$ 1,234,960	$ 1,177,948

Segment Reporting (Schedule O97

Segment Reporting (Schedule Of Geographic Distribution Of Gross Premiums Written) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Geographic Distribution Of Gross Premiums Category [Line Items]
Gross premiums written	$ 4,202,170	$ 3,320,861	$ 2,894,076
United States
Geographic Distribution Of Gross Premiums Category [Line Items]
Gross premiums written	2,823,950	2,305,301	2,054,431
Worldwide
Geographic Distribution Of Gross Premiums Category [Line Items]
Gross premiums written	794,289	566,664	456,078
Europe
Geographic Distribution Of Gross Premiums Category [Line Items]
Gross premiums written	265,100	209,729	172,077
Asia
Geographic Distribution Of Gross Premiums Category [Line Items]
Gross premiums written	105,838	75,165	38,442
Japan
Geographic Distribution Of Gross Premiums Category [Line Items]
Gross premiums written	82,864	58,524	45,618
Australasia
Geographic Distribution Of Gross Premiums Category [Line Items]
Gross premiums written	49,727	41,309	61,994
Other
Geographic Distribution Of Gross Premiums Category [Line Items]
Gross premiums written	$ 80,402	$ 64,169	$ 65,436

Goodwill And Intangible Asset98

Goodwill And Intangible Assets (Narrative) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible asset impairment loss	[1]	$ 0	$ 0	$ (5,450)
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Amortization of intangible assets with finite lives, 2017		63,700
Amortization of intangible assets with finite lives, 2018		37,700
Amortization of intangible assets with finite lives, 2019		27,500
Amortization of intangible assets with finite lives, 2020		22,800
Amortization of intangible assets with finite lives, 2021		21,600
Amortization of intangible assets with finite lives, after 2021		$ 53,000
[1]	For additional information on the Company's intangible assets, see Note 11, Goodwill and intangible assets.

Goodwill And Intangible Asset99

Goodwill And Intangible Assets (Schedule Of Goodwill And Intangible Assets) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Schedule Of Goodwill And Intangible Assets [Line Items]
Net beginning balance		$ 553,960	$ 153,405
Additions		(962)	438,185	[1]
Amortization		(84,624)	(30,620)		$ (6,484)
Goodwill impairment loss		0	0
Intangible asset impairment loss	[2]	0	0		(5,450)
Goodwill and intangible assets, foreign currency translation			7,010
Gross balance		683,732
Intangible assets with finite lives, accumulated amortization		(202,898)
Accumulated impairment losses		(5,450)
Accumulated foreign currency translation		(7,010)
Net balance		468,374	553,960		153,405
Goodwill
Schedule Of Goodwill And Intangible Assets [Line Items]
Net beginning balance		176,455	91,238
Additions		(973)	87,367	[1]
Amortization		0	0
Goodwill, foreign currency translation			(2,150)
Gross balance		177,632
Intangible assets with finite lives, accumulated amortization		0
Goodwill accumulated impairment loss		0
Accumulated foreign currency translation		(2,150)
Net balance		175,482	176,455		91,238
Intangible assets with indefinite lives
Schedule Of Goodwill And Intangible Assets [Line Items]
Net beginning balance		66,641	11,779
Additions		0	57,600	[1]
Amortization		0	0
Indefinite-lived intangible assets, foreign currency translation			(2,738)
Intangible assets with indefinite lives, Gross balance		74,829
Intangible assets with finite lives, accumulated amortization		0
Accumulated impairment losses		(5,450)
Accumulated foreign currency translation		(2,738)
Net balance		66,641	66,641		11,779
Intangible assets with finite lives
Schedule Of Goodwill And Intangible Assets [Line Items]
Net beginning balance		310,864	50,388
Additions		11	293,218	[1]
Amortization		(84,624)	(30,620)
Finite-lived intangible assets, foreign currency translation			(2,122)
Intangible assets with finite lives, Gross balance		431,271
Intangible assets with finite lives, accumulated amortization		(202,898)
Intangible assets with finite lives, accumulated impairment losses		0
Accumulated foreign currency translation		(2,122)
Net balance		$ 226,251	$ 310,864		$ 50,388
[1]	For additional information on the intangible assets acquired during 2015, see Note 3, Acquisition of Montpelier.
[2]	For additional information on the Company's intangible assets, see Note 11, Goodwill and intangible assets.

Commitments And Contingencie100

Commitments And Contingencies (Narrative) (Details) $ in Thousands	Dec. 31, 2016USD ($)custodian	Dec. 31, 2015USD ($)
Commitments and Contingencies Disclosure [Abstract]
Collateral held related to ceded reinsurance agreements	$ 493,300	$ 321,500
Securities pledged as collateral obligation	$ 106,800	108,900
Number of custodians | custodian	6
Ceded Credit Risk [Line Items]
Reinsurance Recoverables	$ 1,486,918	1,195,970
U.S. Government Sponsored Reinsurance Program [Member]
Ceded Credit Risk [Line Items]
Reinsurance Recoverables	141,400	234,600
A- or better by A.M. Best or Standard And Poors [Member]
Ceded Credit Risk [Line Items]
Reinsurance Recoverables	$ 1,293,300	$ 941,500

Commitments And Contingencie101

Commitments And Contingencies (Schedule Of Percentage Of Gross Premiums Written) (Details) - Sales [Member]	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue, Major Customer [Line Items]
Percentage of gross premium written	44.10%	41.80%	42.90%
Marsh & McLennan Companies, Inc.
Revenue, Major Customer [Line Items]
Percentage of gross premium written	20.90%	19.80%	19.10%
Aon Benfield
Revenue, Major Customer [Line Items]
Percentage of gross premium written	14.30%	12.80%	13.20%
Willis Companies
Revenue, Major Customer [Line Items]
Percentage of gross premium written	8.90%	9.20%	10.60%

Commitments And Contingencie102

Commitments And Contingencies (LOC) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Cash and investments pledged under letters of credit facility	$ 252.2	$ 383.3
Amount of letters of credit outstanding	$ 222.3	$ 341.6

Commitments And Contingencie103

Commitments And Contingencies (Deposits) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
United States
Statutory Accounting Practices [Line Items]
Assets Held by Insurance Regulators	$ 207.8	$ 208.3

Commitments And Contingencie104

Commitments And Contingencies (Assets Held In Trust) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets Held In Trust [Line Items]
Cash and cash equivalents	$ 1,149,541	$ 1,177,750	$ 745,472	$ 845,851
Blue Water Re Trust [Member]
Assets Held In Trust [Line Items]
Assets Held-in-trust	427,800	438,900
BW Retrocessional Agreement [Member]
Assets Held In Trust [Line Items]
Cash and cash equivalents	191,400	195,300
Blue Capital Re ILS Trusts [Member]
Assets Held In Trust [Line Items]
Assets Held-in-trust	3,300	5,200
Endurance Reinsurance Trust [Member]
Assets Held In Trust [Line Items]
Assets Held-in-trust	783,900	94,100
Reduced Collateral Trust [Member]
Assets Held In Trust [Line Items]
Assets Held-in-trust	16,400	10,800
MUSIC Trust [Member]
Assets Held In Trust [Line Items]
Assets Held-in-trust	24,600	21,300
Lloyd's Premiums Trust Funds [Member]
Assets Held In Trust [Line Items]
Assets Held-in-trust	184,100	231,900
Endurance Bermuda | Lloyd's Capital Trust [Member]
Assets Held In Trust [Line Items]
Assets Held-in-trust	$ 323,600	$ 276,800

Commitments And Contingencie105

Commitments And Contingencies (Lloyd's New Central Fund) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Levy Imposed As Percentage Of Premiums Written	0.35%	0.50%
Additional Contribution As Percentage Of Underwriting Capacity Maximum	3.00%
Estimated Obligation To Central Fund For Annual Contribution	$ 1.1	$ 1
Annual Subscription Charge As Percentage Of Premium Written	0.45%	0.50%
Estimated Obligation For Annual Subscription Charges	$ 1.4	$ 1

Commitments And Contingencie106

Commitments And Contingencies (Schedule Of Future Minimum Lease Commitments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
2,017	$ 15,895
2,018	19,945
2,019	22,420
2,020	21,060
2,021	19,099
2,022	103,443
Total	201,862
Total lease expense under operating leases	12,800	$ 16,500	$ 14,700
Total sublease income under operating leases	$ 400	$ 1,300	$ 1,300

Shareholders' Equity (Narrative

Shareholders' Equity (Narrative) (Details) $ / shares in Units, $ in Thousands	Jun. 01, 2016$ / sharesshares	Dec. 24, 2015shares	Nov. 24, 2015USD ($)$ / sharesshares	Jun. 01, 2011USD ($)shares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)shares	Dec. 31, 2014USD ($)	Feb. 25, 2016shares
Class of Stock [Line Items]
Preferred Stock, Shares Issued					9,200	9,209,200
Number of restricted shares outstanding					1,396,538
Net proceeds on issuance of preferred shares | $					$ 0	$ 222,963	$ 0
Shares authorized to be repurchased								5,000,000
Treasury Stock, Shares, Acquired					0
Total authorized repurchases remaining shares					5,000,000	5,000,000
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Shares redeemed		8,000,000
Preferred stock, dividend percentage		7.75%
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued				9,200,000		9,200,000
Shares redeemed	9,200,000
Preferred stock, dividend percentage				7.50%
Net proceeds on issuance of preferred shares | $				$ 224,000
Preferred stock redemption price per share | $ / shares	$ 25
Series C Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued			9,200		9,200	0
Preferred stock, dividend percentage			6.35%
Preferred Stock Shares Issued Depositary Shares			9,200,000
Preferred stock price at issue | $ / shares			$ 25,000
Preferred Stock Price At Issue Depositary Shares | $ / shares			$ 25
Net proceeds on issuance of preferred shares | $			$ 222,000
Preferred stock redemption price per share | $ / shares			$ 25,000
Preferred Stock Redemption Price Per Depositary Share | $ / shares			25
Preferred Stock Early Redemption Amount Depositary Share | $ / shares			26
Preferred stock redemption price per share before stated redemption date | $ / shares			26,000
Preferred stock, liquidation price per share | $ / shares			25,000
Preferred Stock Liquidation Preference Depositary Shares | $ / shares			$ 25
Preferred Stock Interest In Share			0.001

Shareholders' Equity (Schedule

Shareholders' Equity (Schedule Of Company's Share Capital) (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Capital Unit [Line Items]
Preferred Stock, Shares Authorized	9,200	9,209,200
Preferred Stock, Shares Issued	9,200	9,209,200
Preferred Stock, Shares Outstanding	9,200	9,209,200
Common Stock, Shares Authorized	120,000,000	120,000,000
Common shares, ordinary, number of shares issued	67,627,901	66,797,991
Common shares, ordinary, number of shares outstanding	67,627,901	66,797,991
Preferred Stock, Par or Stated Value Per Share	$ 1
Common Stock, Par or Stated Value Per Share	$ 1
Preferred shares, total liquidation preference	$ 230,000	$ 460,000
Series B Preferred Stock [Member]
Capital Unit [Line Items]
Preferred Stock, Shares Issued	0	9,200,000
Preferred Stock, Shares Outstanding	0	9,200,000
Preferred Stock, Par or Stated Value Per Share		$ 1
Preferred shares, total liquidation preference	$ 0	$ 230,000
Series C Preferred Stock [Member]
Capital Unit [Line Items]
Preferred Stock, Shares Issued	9,200	9,200
Preferred Stock, Shares Outstanding	9,200	9,200
Preferred Stock, Par or Stated Value Per Share	$ 1
Preferred shares, total liquidation preference	$ 230,000	$ 230,000

Shareholders' Equity (Schedu109

Shareholders' Equity (Schedule Of Changes In Accumulated Other Comprehensive (Loss) Income By Component) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive (Loss) Income [Line Items]
Beginning balance		$ (46,634)	$ 76,706
Other comprehensive (loss) income before reclassifications		(32,037)	(90,631)
Amounts reclassified from accumulated other comprehensive loss	[1]	19,922	(32,709)
Net current period other comprehensive loss		(12,115)	(123,340)	$ 13,975
Ending balance		(58,749)	(46,634)	76,706
Losses on cash flow hedges
Accumulated Other Comprehensive (Loss) Income [Line Items]
Beginning balance		(1,678)	(1,766)
Other comprehensive (loss) income before reclassifications		0	0
Amounts reclassified from accumulated other comprehensive loss	[1]	88	88
Net current period other comprehensive loss		88	88
Ending balance		(1,590)	(1,678)	(1,766)
Unrealized (losses) gains on available for sale securities
Accumulated Other Comprehensive (Loss) Income [Line Items]
Beginning balance		(12,638)	86,100
Other comprehensive (loss) income before reclassifications		54,287	(65,941)
Amounts reclassified from accumulated other comprehensive loss	[1]	19,834	(32,797)
Net current period other comprehensive loss		74,121	(98,738)
Ending balance		61,483	(12,638)	86,100
Foreign currency translation adjustments
Accumulated Other Comprehensive (Loss) Income [Line Items]
Beginning balance		(32,318)	(7,628)
Other comprehensive (loss) income before reclassifications		(86,324)	(24,690)
Amounts reclassified from accumulated other comprehensive loss	[1]	0	0
Net current period other comprehensive loss		(86,324)	(24,690)
Ending balance		$ (118,642)	$ (32,318)	$ (7,628)
[1]	All amounts are net of tax.

Shareholders' Equity (Schedu110

Shareholders' Equity (Schedule Of Reclassifications Out Of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Interest expense									$ 43,860	$ 41,260	$ 40,968
Net realized and unrealized (losses) gains	$ 45,958	$ (13,405)	$ (6,347)	$ (13,787)	$ 20,238	$ (5,029)	$ (9,680)	$ (18,189)	12,419	(12,660)	(14,283)
Net impairment losses recognized in earnings	122	183	9,841	623	2,604	38	424	649	10,769	3,715	625
Income before income taxes									(380,966)	(359,473)	(348,840)
Income tax benefit (expense)									181	(4,362)	(390)
Total net of income taxes	$ (23,801)	$ (133,721)	$ (83,914)	$ (115,581)	$ (99,587)	$ (51,823)	$ (84,206)	$ (108,479)	(357,017)	(344,095)	$ (348,450)
Reclassification Adjustment Out Of Accumulated Other Comprehensive (Loss) Income [Member] | Losses on cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Interest expense									88	88
Income before income taxes									88	88
Income tax benefit (expense)									0	0
Total net of income taxes									88	88
Reclassification Adjustment Out Of Accumulated Other Comprehensive (Loss) Income [Member] | Unrealized losses (gains) on available for sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Net realized and unrealized (losses) gains									7,984	(37,245)
Net impairment losses recognized in earnings									10,769	3,715
Income before income taxes									18,753	(33,530)
Income tax benefit (expense)									(1,081)	(733)
Total net of income taxes									$ 19,834	$ (32,797)

Earnings Per Share (Schedule Of

Earnings Per Share (Schedule Of Computation Of Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income available to common and participating common shareholders		$ 20,149	$ 130,070	$ 76,621	$ 106,378	$ 91,401	$ 43,635	$ 76,018	$ 100,291	$ 333,218	$ 311,345	$ 315,700
Less amount allocated to participating common shareholders	[1]									(6,973)	(8,749)	(9,118)
Net income allocated to common shareholders										$ 326,245	$ 302,596	$ 306,582
Weighted average shares - basic										65,991,947	52,707,390	43,368,062
Weighted average shares - diluted										66,135,373	52,828,503	43,415,243
Basic earnings per common share		$ 0.30	$ 1.93	$ 1.14	$ 1.58	$ 1.36	$ 0.73	$ 1.69	$ 2.24	$ 4.94	$ 5.74	$ 7.07
Diluted earnings per common share		$ 0.30	$ 1.92	$ 1.14	$ 1.58	$ 1.36	$ 0.73	$ 1.68	$ 2.23	$ 4.93	$ 5.73	$ 7.06
Restricted Stock [Member]
Share equivalents:										78,075	2,721	70
Employee Stock Option [Member]
Share equivalents:										65,351	118,392	47,111
[1]	Represents earnings and dividends attributable to holders of unvested restricted shares and restricted share units issued under the Company's stock compensation plans that are considered participating. In periods of loss, no losses are allocated to participating common shareholders (unvested restricted shares and restricted share units).

Earnings Per Share (Schedule112

Earnings Per Share (Schedule Of Dividends Declared) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Dividends Declared [Line Items]
Dividends declared per common share	$ 1.52	$ 1.40	$ 1.36
Series A Preferred Stock [Member]
Dividends Declared [Line Items]
Dividends declared per preferred share	0	1.937500	1.937500
Series B Preferred Stock [Member]
Dividends Declared [Line Items]
Dividends declared per preferred share	0.8646	1.875000	1.875000
Series C Preferred Stock [Member]
Dividends Declared [Line Items]
Dividends declared per preferred share	$ 1,680.10	$ 0	$ 0

Earnings Per Share (Narrative)

Earnings Per Share (Narrative) (Details) - Series B Preferred Stock [Member]	Jun. 01, 2016$ / sharesshares
Class of Stock [Line Items]
Shares redeemed | shares	9,200,000
Preferred stock redemption price per share | $ / shares	$ 25

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands, shares in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Investment expenses	$ 16,525	$ 16,486	$ 14,284
BlackRock Inc [Member]
Related Party Transaction [Line Items]
Ordinary shares owned by related parties	4.9
Percentage of ordinary shares owned by related parties	7.30%
Investment expenses	$ 4,600	3,600	$ 3,200
Accrued investment expenses	$ 2,800	$ 1,600

Stock-Based Employee Compens115

Stock-Based Employee Compensation And Other Stock Plans (Narrative) (Details)

Aug. 03, 2015shares

Jul. 31, 2015shares

May 28, 2013shares

Dec. 31, 2016USD ($)shares

Dec. 31, 2015USD ($)shares

Dec. 31, 2014USD ($)shares

May 20, 2015shares

May 11, 2011shares

Feb. 23, 2011shares

Feb. 11, 2010shares

Feb. 28, 2007shares

Oct. 26, 2005shares

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of ordinary shares authorized for issuance

2,071,035

2,463,798

Number of additional ordinary shares authorized after acquisition of Montpelier

842,755

Contractual life of stock options

10 years

Number of options granted

0

Number of options expired

0

0

0

Number of options vested

160,000

160,000

160,000

Number of options exercised

160,000

Total intrinsic value of options exercised | $

$ 3,200,000

$ 9,500,000

$ 300,000

Proceeds from stock options exercised | $

7,700,000

Unrecognized stock based compensation expenses related to unvested stock options | $

$ 200,000

$ 1,000,000

Vesting period for employee awards

4 years

Restricted share awards to non-employee directors, vesting period

1 year

Number of restricted shares granted

638,217

1,388,179

505,997

Restricted shares weighted average grant date, aggregate fair value | $

$ 38,500,000

$ 91,200,000

$ 26,700,000

Aggregate fair value of restricted shares and RSUs vested | $

44,300,000

60,000,000

18,700,000

Compensation costs not yet recognized related to unvested restricted shares and restricted share units | $

$ 26,200,000

$ 26,700,000

Exchange ratio

0.472

RSUs assumed

841,926

Weighted average remaining contractual life in years, options outstanding, end of year

6 years 4 months 28 days

Employee Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock options vesting rate

20.00%

Contractual life of stock options

10 years

Vesting period for employee awards

5 years

Compensation costs recognized | $

$ 800,000

$ 1,600,000

3,100,000

Restricted Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period for employee awards

4 years

Restricted share awards to non-employee directors, vesting period

12 months

Compensation costs recognized | $

$ 35,700,000

53,900,000

27,900,000

Percentage of compensation expense to be expensed next year

65.30%

Performance Shares [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period for employee awards

3 years

Stock Based Employee Compensation Plans Two Thousand Seven Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of ordinary shares authorized for issuance

5,763,104

1,795,000

2,100,000

Number of additional ordinary shares authorized after acquisition of Montpelier

1,025,349

2005 Employee Share Purchase Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Shares reserved for issuance under ESPP

400,000

200,000

200,000

2015 Employee Stock Purchase Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Period shares are restricted from sale, transfer, or certification

1 year

Shares reserved for issuance under ESPP

300,000

Percentage of employee share purchase plans discount closing market price

15.00%

Expenses related to employee stock purchase plan | $

$ 425,000

$ 298,000

$ 234,000

Chief Executive Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of restricted shares granted

708,890

Share-based Compensation Award, Tranche One [Member] | Performance Shares [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting rate of restricted shares on death, disability or change of control, percentage

50.00%

Restricted Stock [Member] | Chief Executive Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of tranches

5

Stock-Based Employee Compens116

Stock-Based Employee Compensation And Other Stock Plans (Options Narrative) (Details)	May 28, 2013$ / sharesshares	Dec. 31, 2016$ / sharesshares	Dec. 31, 2015shares	Dec. 31, 2014shares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of options granted		0
Weighted average exercise price of options granted in period | $ / shares		$ 0
Number of options expired		0	0	0
Contractual life of stock options	10 years
Chief Executive Officer [Member]
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of options granted	800,000
Weighted average exercise price of options granted in period | $ / shares	$ 48.20
Chief Executive Officer [Member] | Employee Stock Option [Member]
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of tranches	5
Chief Executive Officer [Member] | Restricted Stock [Member]
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of tranches	5

Stock-Based Employee Compens117

Stock-Based Employee Compensation And Other Stock Plans (Summary Of Stock Option Activity) (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Weighted average remaining contractual life in years, options outstanding, end of year	6 years 4 months 28 days
Number of options granted	0
Aggregate Intrinsic Value, Outstanding, end of year | $	$ 7,072
Aggregate Intrinsic Value, Exercisable and vested options, end of year | $	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of options, beginning of year	320,000
Number of options granted	0
Number of options exercised	(160,000)
Number of options forfeited	0
Number of options outstanding, end of year	160,000
Number of options exercisable and vested, end of year	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price, Beginning of year | $ / shares	$ 48.20
Weighted average Exercise Price, Granted | $ / shares	0
Weighted Average Exercise Price, Exercised | $ / shares	48.20
Weighted Average Exercise Price, Forfeited | $ / shares	0
Weighted Average Exercise Price, Outstanding, end of year | $ / shares	48.20
Weighted Average Exercise Price, Exercisable and vested options, end of year | $ / shares	$ 0

Stock-Based Employee Compens118

Stock-Based Employee Compensation And Other Stock Plans (Restricted Share And Restricted Share Unit Activity) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested, beginning of year	1,663,582
Granted	638,217
Settled	(769,445)
Forfeited	(65,638)
Unvested, end of year	1,466,716
Number of Shares/Units, Outstanding, end of year	1,663,582	1,466,716
Aggregate Intrinsic Value, Outstanding, end of year		$ 135,525

Pension Plan (Details)

Pension Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Contribution Plan Disclosure [Line Items]
Expenses related to contributions	$ 15.8	$ 13.8	$ 12.6
Low
Defined Contribution Plan Disclosure [Line Items]
Percentage of defined contributions per employee	4.00%
High
Defined Contribution Plan Disclosure [Line Items]
Percentage of defined contributions per employee	12.00%

Statutory Requirements And D120

Statutory Requirements And Dividend Restrictions (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Statutory Requirements And Dividend Restrictions [Line Items]
Retained earnings	$ 2,911,634	$ 2,681,053
Contributed surplus	$ 1,961,917	2,145,836
Period to notify the PRA, days	28 days
Armtech [Member]
Statutory Requirements And Dividend Restrictions [Line Items]
Payable dividend without prior regulatory approval	$ 3,300	3,500
Endurance Bermuda
Statutory Requirements And Dividend Restrictions [Line Items]
Payable dividend without prior regulatory approval	1,109,300	1,034,400
Endurance Bermuda | Low
Statutory Requirements And Dividend Restrictions [Line Items]
Required statutory capital	$ 100,000
Endurance US Subsidiaries
Statutory Requirements And Dividend Restrictions [Line Items]
Dividend payable rate, maximum	10.00%
Blue Water Re
Statutory Requirements And Dividend Restrictions [Line Items]
Statutory net assets	$ 263,100	269,600
Blue Water Re II
Statutory Requirements And Dividend Restrictions [Line Items]
Statutory net assets	11,300	212,500
Blue Capital Re
Statutory Requirements And Dividend Restrictions [Line Items]
Payable dividend without prior regulatory approval	45,900	50,600
Lloyd's Capital Trust [Member] | Endurance Bermuda
Statutory Requirements And Dividend Restrictions [Line Items]
Assets Held-in-trust	$ 323,600	$ 276,800

Statutory Requirements And D121

Statutory Requirements And Dividend Restrictions (Combined Statutory Capital and Statutory Net Income (Loss)) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Bermuda
Statutory Accounting Practices [Line Items]
Required statutory capital	[1],[2]	$ 1,614,465	$ 1,276,453
Actual statutory capital	[1],[2]	4,525,290	4,307,249
Statutory net income (loss)		486,254	417,298	$ 453,127
United States
Statutory Accounting Practices [Line Items]
Required statutory capital		350,947	281,905
Actual statutory capital		810,704	768,791
Statutory net income (loss)		64,688	70,398	28,450
United Kingdom
Statutory Accounting Practices [Line Items]
Required statutory capital	[3]	184,799	84,086
Actual statutory capital	[3]	451,257	538,265
Statutory net income (loss)		79,912	969	4,135
Singapore
Statutory Accounting Practices [Line Items]
Required statutory capital		3,461	3,524
Actual statutory capital		59,025	49,842
Statutory net income (loss)		$ 10,460	$ 17,542	$ 4,111
[1]	{F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOjc3NjNhMmJhMjQ4MzRmYjk4MWUzOWY1YzBlMDY4OGYyfFRleHRTZWxlY3Rpb246NEE0NDk0MDYwMUIwMUFDMEI0OUMwREQ2MkVFREFCMkYM}
[2]	{F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOjc3NjNhMmJhMjQ4MzRmYjk4MWUzOWY1YzBlMDY4OGYyfFRleHRTZWxlY3Rpb246NUVCNEIwRkQ4MjUxNDNBNDJENzIwREQ2MkVFREU0NzAM}
[3]	U.K. includes the statutory capital of Endurance U.K.

Taxes (Narrative) (Details)

Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Expense Benefit [Line Items]
Current income tax expense	$ (10,993)	$ (6,262)	$ (1,804)
Deferred income tax benefit	$ 11,174	1,900	1,414
Combined effective tax rate (Bermuda)	0.00%
Total income tax paid	$ (7,800)	(2,400)	(900)
Valuation allowance	(104,808)	(131,138)
United States
Income Tax Expense Benefit [Line Items]
Current income tax expense	1,800	4,200	1,800
Deferred income tax benefit	(5,200)	(700)	$ (1,400)
Net operating loss carryforwards	119,800
United Kingdom
Income Tax Expense Benefit [Line Items]
Current income tax expense	4,200	2,200
Deferred income tax benefit	(1,700)	(200)
Net operating loss carryforwards	45,900
Switzerland
Income Tax Expense Benefit [Line Items]
Current income tax expense	5,000	0
Net operating loss carryforwards	44,500
Singapore
Income Tax Expense Benefit [Line Items]
Net operating loss carryforwards	61,100
Bermuda
Income Tax Expense Benefit [Line Items]
Deferred income tax benefit	$ (4,200)	$ (1,000)

Taxes (Income Tax Expense) (Det

Taxes (Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Current income tax expense	$ (10,993)	$ (6,262)	$ (1,804)
Deferred income tax benefit	11,174	1,900	1,414
Income tax benefit (expense)	$ 181	$ (4,362)	$ (390)

Taxes (Income Tax Rate Reconcil

Taxes (Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Computed expected tax expense	$ 0	$ 0	$ 0
Tax expense effect on foreign taxes	(26,149)	(8,071)	(1,661)
Change in valuation allowance	26,330	3,709	1,271
Income tax benefit (expense)	$ 181	$ (4,362)	$ (390)

Taxes (Schedule Of Net Deferred

Taxes (Schedule Of Net Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Unearned premiums	$ 28,523	$ 25,172
Loss reserves	26,594	27,370
Net operating loss carryforward	66,315	92,844
Deferred compensation	26,451	25,268
Deferred interest	48,359	46,568
Unrealized investment losses	1,803	1,568
Realized investment losses	4,010	4,972
Other	3,830	11,077
Total deferred income tax assets	205,885	234,839
Deferred acquisition costs	(1,325)	(8,179)
Unrealized foreign exchange gains	0	(4,087)
Temporary differences related to acquisition	(29,033)	(35,461)
Start up costs	(1,989)	(1,565)
Other	(10,002)	(7,561)
Total deferred income tax liabilities	(42,349)	(56,853)
Valuation allowance	(104,808)	(131,138)
Net deferred income tax asset	$ 58,728	$ 46,848

Taxes (Schedule Of Distribution

Taxes (Schedule Of Distribution Of Income Before Income Taxes) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
U.S. (domestic)		$ 40,872	$ 95,649	$ 60,112
Non-U.S. (foreign)	[1]	340,094	263,824	288,728
Income before income taxes		$ 380,966	$ 359,473	$ 348,840
[1]	The Company's non-U.S. (foreign) operating subsidiaries write business that is exposed to risks originating in the United States.

Taxes (Montpelier Valuation All

Taxes (Montpelier Valuation Allowance) (Details) - Montpelier Re Holdings Ltd [Member] $ in Millions	Dec. 31, 2016USD ($)
Valuation Allowance [Line Items]
Operating Loss Carryforwards, Valuation Allowance	$ 11.6
Capital Loss Carryforwards Valuation Allowance	0.7
Loss Carryforward Available Per Year	$ 0.2

Condensed Unaudited Quarterl128

Condensed Unaudited Quarterly Financial Data (Summary Of The Unaudited Quarterly Data) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								5 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Net premiums earned	$ 600,705	$ 610,156	$ 599,608	$ 553,191	$ 573,456	$ 557,003	$ 458,135	$ 389,859		$ 2,363,660	$ 1,978,453	$ 1,863,978
Net investment income	59,196	62,236	43,977	11,181	23,180	16,533	32,252	41,861		176,590	113,826	131,543
Net realized and unrealized gains	(45,958)	13,405	6,347	13,787	(20,238)	5,029	9,680	18,189		(12,419)	12,660	14,283
Net impairment losses recognized in earnings	(122)	(183)	(9,841)	(623)	(2,604)	(38)	(424)	(649)		(10,769)	(3,715)	(625)
Subtotal	613,821	685,614	640,091	577,536	573,794	578,527	499,643	449,260
Net losses and loss expenses	370,150	331,462	376,112	243,328	242,057	263,993	239,122	171,936		1,321,052	917,108	970,162
Acquisition, general and administrative, and corporate expenses	192,546	201,081	178,870	187,838	194,726	225,558	152,570	149,251
Net foreign exchange (gains) losses	(11,628)	(18,576)	(32,751)	(11,729)	(2,190)	8,621	12,981	7,552		(74,684)	26,964	3,839
Net income	29,475	139,400	87,628	124,644	107,896	54,530	84,206	108,479		381,147	355,111	348,450
Net income attributable to non-controlling interests	(5,674)	(5,679)	(3,714)	(9,063)	(8,309)	(2,707)	0	0	$ (11,016)	(24,130)	(11,016)	0
Net income available to Endurance Holdings	23,801	133,721	83,914	115,581	99,587	51,823	84,206	108,479		357,017	344,095	348,450
Preferred dividends	(3,652)	(3,651)	(7,293)	(9,203)	(8,186)	(8,188)	(8,188)	(8,188)		(23,799)	(32,750)	(32,750)
Net income available to Endurance Holdings' common and participating common shareholders	$ 20,149	$ 130,070	$ 76,621	$ 106,378	$ 91,401	$ 43,635	$ 76,018	$ 100,291		$ 333,218	$ 311,345	$ 315,700
Basic earnings per share	$ 0.30	$ 1.93	$ 1.14	$ 1.58	$ 1.36	$ 0.73	$ 1.69	$ 2.24		$ 4.94	$ 5.74	$ 7.07
Diluted earnings per share	$ 0.30	$ 1.92	$ 1.14	$ 1.58	$ 1.36	$ 0.73	$ 1.68	$ 2.23		$ 4.93	$ 5.73	$ 7.06

Schedule I Summary Of Invest129

Schedule I Summary Of Investments Other Than Investments In Related Parties (Summary Of Investments Other Than Investments In Related Parties) (Details) $ in Thousands	Dec. 31, 2016USD ($)
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	$ 7,622,386	[1]
Market Value	7,810,974
Amount at Which Shown on the Balance Sheet	7,810,974
Fixed maturity investments
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	6,265,498	[1]
Market Value	6,312,821
Amount at Which Shown on the Balance Sheet	6,312,821
Short-term investments
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	408,811	[1]
Market Value	408,704
Amount at Which Shown on the Balance Sheet	408,704
Equity securities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	477,778	[1]
Market Value	501,141
Amount at Which Shown on the Balance Sheet	501,141
Other investments
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	470,299	[1]
Market Value	588,308
Amount at Which Shown on the Balance Sheet	588,308
U.S. government and government agencies and authorities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	1,003,969	[1]
Market Value	1,001,882
Amount at Which Shown on the Balance Sheet	1,001,882
States, municipalities and political subdivisions
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	17,115	[1]
Market Value	18,357
Amount at Which Shown on the Balance Sheet	18,357
Foreign governments
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	180,583	[1]
Market Value	178,919
Amount at Which Shown on the Balance Sheet	178,919
Corporate bonds
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	2,120,463	[1]
Market Value	2,151,610
Amount at Which Shown on the Balance Sheet	2,151,610
Agency mortgage-backed securities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	1,461,354	[1]
Market Value	1,472,343
Amount at Which Shown on the Balance Sheet	1,472,343
Non-agency mortgage-backed securities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	603,293	[1]
Market Value	607,791
Amount at Which Shown on the Balance Sheet	607,791
Collateralized loan and debt obligations
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	369,126	[1]
Market Value	371,256
Amount at Which Shown on the Balance Sheet	371,256
Asset-backed securities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	509,595	[1]
Market Value	510,663
Amount at Which Shown on the Balance Sheet	$ 510,663
[1]	Investments in fixed maturity investments and short-term investments are shown at amortized cost.

Schedule II Condensed Financ130

Schedule II Condensed Financial Statement Information Of The Registrant (Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Jul. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Preferred Stock, Shares Issued	9,200	9,209,200
Preferred Stock, Shares Outstanding	9,200	9,209,200
Common shares, ordinary, number of shares issued	67,627,901	66,797,991
Common shares, ordinary, number of shares outstanding	67,627,901	66,797,991
Assets [Abstract]
Cash and cash equivalents	$ 1,149,541	$ 1,177,750		$ 745,472	$ 845,851
Goodwill and intangible assets	468,374	553,960		153,405
Other assets	288,510	187,383
Total assets	14,122,861	13,241,525
Liabilities [Abstract]
Debt	705,292	717,650
Deferred tax liability	13,074	17,315
Other liabilities	383,036	344,596
Total liabilities	8,980,728	8,117,453
Stockholders' Equity Attributable to Parent [Abstract]
Series B and C, non-cumulative - 9,200 issued and outstanding (2015 - 9,209,200)	9	9,209
Common shares, ordinary - 67,627,901 issued and outstanding (2015 - 66,797,991)	67,628	66,798
Additional paid-in capital	1,961,917	2,145,836
Accumulated other comprehensive loss	(58,749)	(46,634)		76,706
Retained earnings	2,911,634	2,681,053
Total shareholders' equity available to Endurance Holdings	4,882,439	4,856,262		3,185,182
Non-controlling interests	259,694	267,810	$ 258,529	0
Total shareholders' equity	5,142,133	5,124,072		3,185,182
Total liabilities and shareholders' equity	$ 14,122,861	$ 13,241,525
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Preferred Stock, Shares Issued	9,200	9,209,200
Preferred Stock, Shares Outstanding	9,200	9,209,200
Common shares, ordinary, number of shares issued	67,627,901	66,797,991
Common shares, ordinary, number of shares outstanding	67,627,901	66,797,991
Assets [Abstract]
Investment in subsidiary	$ 5,296,821	$ 5,683,801
Cash and cash equivalents	3,375	3,206		$ 240	$ 6,517
Amounts due from subsidiaries	513,621	105,497
Goodwill and intangible assets	45,710	51,938
Other assets	12,833	14,435
Total assets	5,872,360	5,858,877
Liabilities [Abstract]
Debt	708,378	707,591
Other liabilities	21,849	27,214
Total liabilities	730,227	734,805
Stockholders' Equity Attributable to Parent [Abstract]
Series B and C, non-cumulative - 9,200 issued and outstanding (2015 - 9,209,200)	9	9,209
Common shares, ordinary - 67,627,901 issued and outstanding (2015 - 66,797,991)	67,628	66,798
Additional paid-in capital	1,961,917	2,145,836
Accumulated other comprehensive loss	(58,749)	(46,634)
Retained earnings	2,911,634	2,681,053
Total shareholders' equity available to Endurance Holdings	4,882,439	4,856,262
Non-controlling interests	259,694	267,810
Total shareholders' equity	5,142,133	5,124,072
Total liabilities and shareholders' equity	$ 5,872,360	$ 5,858,877

Schedule II Condensed Financ131

Schedule II Condensed Financial Statement Information Of The Registrant (Statements of Income) (Details) - USD ($) $ in Thousands	3 Months Ended								5 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues
Net investment income	$ 59,196	$ 62,236	$ 43,977	$ 11,181	$ 23,180	$ 16,533	$ 32,252	$ 41,861		$ 176,590	$ 113,826	$ 131,543
Net realized and unrealized gains	(45,958)	13,405	6,347	13,787	(20,238)	5,029	9,680	18,189		(12,419)	12,660	14,283
Total revenues										2,516,153	2,097,530	2,003,393
Expenses
General and administrative expenses										248,146	259,791	247,387
Amortization of intangibles										84,624	30,620	6,484
Net foreign exchange (gains) losses	(11,628)	(18,576)	(32,751)	(11,729)	(2,190)	8,621	12,981	7,552		(74,684)	26,964	3,839
Interest expense										43,860	41,260	40,968
Income before income taxes										380,966	359,473	348,840
Income tax benefit										181	(4,362)	(390)
Net income	29,475	139,400	87,628	124,644	107,896	54,530	84,206	108,479		381,147	355,111	348,450
Net income attributable to non-controlling interests	(5,674)	(5,679)	(3,714)	(9,063)	(8,309)	(2,707)	0	0	$ (11,016)	(24,130)	(11,016)	0
Net income available to Endurance Holdings	23,801	133,721	83,914	115,581	99,587	51,823	84,206	108,479		357,017	344,095	348,450
Preferred dividends	(3,652)	(3,651)	(7,293)	(9,203)	(8,186)	(8,188)	(8,188)	(8,188)		(23,799)	(32,750)	(32,750)
Net income available to common and participating common shareholders	$ 20,149	$ 130,070	$ 76,621	$ 106,378	$ 91,401	$ 43,635	$ 76,018	$ 100,291		333,218	311,345	315,700
Parent Company [Member]
Revenues
Net investment income										5	9	248
Net realized and unrealized gains										206	332	1,957
Other income										10,200	10,200	10,200
Total revenues										10,411	10,541	12,405
Expenses
General and administrative expenses										41,879	93,237	61,325
Amortization of intangibles										6,228	1,558	0
Net foreign exchange (gains) losses										(20)	5	(1)
Interest expense										43,833	41,188	40,968
Total expenses										91,920	135,988	102,292
Loss before income taxes and equity in net income of subsidiaries										(81,509)	(125,447)	(89,887)
Equity in net income of subsidiaries										462,656	480,558	438,337
Net income										381,147	355,111	348,450
Net income attributable to non-controlling interests										(24,130)	(11,016)	0
Net income available to Endurance Holdings										357,017	344,095	348,450
Preferred dividends										(23,799)	(32,750)	(32,750)
Net income available to common and participating common shareholders										$ 333,218	$ 311,345	$ 315,700

Schedule II Condensed Financ132

Schedule II Condensed Financial Statement Information Of The Registrant (Statements Of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows used in operating activities:
Net income	$ 29,475	$ 139,400	$ 87,628	$ 124,644	$ 107,896	$ 54,530	$ 84,206	$ 108,479	$ 381,147	$ 355,111	$ 348,450
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization									105,026	51,457	27,234
Net realized and unrealized gains									12,419	(12,660)	(14,283)
Deferred taxes									(19,709)	(2,727)	(1,414)
Stock-based compensation expense									36,445	55,512	31,006
Other assets									(6,855)	(25,683)	(17,132)
Other liabilities									(28,081)	76,194	127,037
Net cash flows provided by operating activities									415,492	245,457	266,261
Cash flows provided by investing activities:
Proceeds from sales and maturities of available for sale investments									3,477,688	5,725,794	4,145,940
Purchases of available for sale investments									(2,752,599)	(5,421,949)	(4,449,225)
Purchases of fixed assets									(17,568)	(26,988)	(40,932)
Net cash flows (used in) provided by investing activities									(19,222)	486,793	(236,881)
Cash flows used in financing activities
Issuance of common shares									10,076	24,823	2,305
Issuance of Series C, non-cumulative preferred shares									0	222,963	0
Redemption of Series A and B, non-cumulative preferred shares									(230,000)	(200,000)	0
Offering and registration costs paid									(319)	(617)	0
Bridge facility costs paid									0	0	(4,750)
Settlement of restricted shares									(11,732)	(14,535)	(4,039)
Repayments of debt									(13,683)	(199,454)	(686)
Dividends paid on preferred shares									(23,799)	(32,750)	(32,750)
Dividends paid on common shares									(102,417)	(78,473)	(60,524)
Net cash flows used in financing activities									(403,583)	(274,774)	(99,738)
Net (decrease) increase in cash and cash equivalents									(28,209)	432,278	(100,379)
Cash and cash equivalents, beginning of year				1,177,750				745,472	1,177,750	745,472	845,851
Cash and cash equivalents, end of year	1,149,541				1,177,750				1,149,541	1,177,750	745,472
Parent Company [Member]
Cash flows used in operating activities:
Net income									381,147	355,111	348,450
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization									8,380	3,738	6,785
Net realized and unrealized gains									(206)	(332)	(1,957)
Stock-based compensation expense									9,339	28,604	15,093
Equity in net earnings of subsidiary									(462,656)	(480,558)	(438,337)
Other assets									327	(893)	(177)
Other liabilities									(3,524)	(17,377)	1,626
Net cash flows provided by operating activities									(67,193)	(111,707)	(68,517)
Cash flows provided by investing activities:
Proceeds from sales and maturities of available for sale investments									0	0	26,094
Purchases of available for sale investments									0	0	(24,137)
Contributions of capital made to subsidiaries									4,655	0	0
Dividends received from subsidiary									809,840	341,524	145,203
Net amounts paid to subsidiaries									(379,632)	35,383	14,819
Purchases of fixed assets									0	(11,626)	0
Proceeds from disposals of fixed assets									0	6,606	19
Net cash received for subsidiary acquisition									0	19,875	0
Net cash flows (used in) provided by investing activities									425,553	391,762	161,998
Cash flows used in financing activities
Issuance of common shares									10,076	24,823	2,305
Issuance of Series C, non-cumulative preferred shares									0	222,963	0
Redemption of Series A and B, non-cumulative preferred shares									(230,000)	(200,000)	0
Offering and registration costs paid									(319)	(617)	0
Bridge facility costs paid									0	0	(4,750)
Settlement of restricted shares									(11,732)	(14,535)	(4,039)
Repayments of debt									0	(198,500)	0
Dividends paid on preferred shares									(23,799)	(32,750)	(32,750)
Dividends paid on common shares									(102,417)	(78,473)	(60,524)
Net cash flows used in financing activities									(358,191)	(277,089)	(99,758)
Net (decrease) increase in cash and cash equivalents									169	2,966	(6,277)
Cash and cash equivalents, beginning of year				$ 3,206				$ 240	3,206	240	6,517
Cash and cash equivalents, end of year	$ 3,375				$ 3,206				$ 3,375	$ 3,206	$ 240

Schedule III Supplementary I133

Schedule III Supplementary Insurance Information (Supplementary Insurance Information) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs		$ 276,639	$ 255,501	$ 207,368
Reserve for Losses and Loss Expenses		4,905,138	4,510,415	3,846,859
Unearned Premiums		1,994,676	1,789,148	1,254,519
Net Premiums Earned		2,363,660	1,978,453	1,863,978
Net Investment Income	[1]	176,590	113,826	131,543
Net Losses and Loss Expenses		1,321,052	917,108	970,162
Amortization of Deferred Acquisition Costs		460,483	347,885	319,513
Other Operating Expenses	[2]	248,146	259,791	247,387
Net Premiums Written		2,369,935	1,950,470	1,934,206
Reinsurance
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs		204,137	197,285	172,787
Reserve for Losses and Loss Expenses		2,106,149	2,016,521	1,723,087
Unearned Premiums		870,317	886,996	611,740
Net Premiums Earned		1,354,285	1,153,901	1,030,066
Net Investment Income	[1]	0	0	0
Net Losses and Loss Expenses		636,874	416,241	375,601
Amortization of Deferred Acquisition Costs		310,720	267,633	254,145
Other Operating Expenses	[2]	107,404	119,779	98,912
Net Premiums Written		1,313,681	1,070,097	1,073,800
Insurance
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs		72,502	58,216	34,581
Reserve for Losses and Loss Expenses		2,798,989	2,493,894	2,123,772
Unearned Premiums		1,124,359	902,152	642,779
Net Premiums Earned		1,009,375	824,552	833,912
Net Investment Income	[1]	0	0	0
Net Losses and Loss Expenses		684,178	500,867	594,561
Amortization of Deferred Acquisition Costs		149,763	80,252	65,368
Other Operating Expenses	[2]	140,742	140,012	148,475
Net Premiums Written		$ 1,056,254	$ 880,373	$ 860,406
[1]	Because the Company does not manage its assets by segment, investment income is not allocated to the individual segments.
[2]	General and administrative expenses incurred by segments are allocated directly. Remaining general and administrative expenses not incurred by the segments are classified as corporate expenses and are not allocated to the individual business segments.

Schedule IV Reinsurance (Summar

Schedule IV Reinsurance (Summary Of Reinsurance) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount	$ 2,570,494	$ 2,085,901	$ 1,716,128
Ceded to Other Companies	1,832,235	1,370,391	959,870
Assumed from Other Companies	1,631,676	1,234,960	1,177,948
Net premiums written	2,369,935	1,950,470	1,934,206
Property and liability insurance
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount	2,570,494	2,085,901	1,716,128
Ceded to Other Companies	1,832,235	1,370,391	959,870
Assumed from Other Companies	1,631,676	1,234,960	1,177,948
Net premiums written	$ 2,369,935	$ 1,950,470	$ 1,934,206
Percentage of Amount Assumed to Net	69.00%	63.00%	61.00%

Schedule V - Valuation and Q135

Schedule V - Valuation and Qualifying Accounts (Details) - Valuation allowance for deferred tax assets - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year		$ 131,138	$ 121,409	$ 122,680
Charged to costs and expenses		0	0	0
Charged to other accounts		0	13,300	0
Deductions	[1]	26,330	3,571	1,271
Balance at End of Year		$ 104,808	$ 131,138	$ 121,409
[1]	Credited to the related asset account

Schedule VI Underwriters (Sched

Schedule VI Underwriters (Schedule Of Underwriters) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Deferred Acquisition Costs		$ 276,639	$ 255,501	$ 207,368
Reserve for Losses and Loss Expenses		4,905,138	4,510,415	3,846,859
Discount if any, Reserve for Losses and Loss Expenses		0	0	0
Unearned Premiums		1,994,676	1,789,148	1,254,519
Net Premiums Earned		2,363,660	1,978,453	1,863,978
Net Investment Income	[1]	176,590	113,826	131,543
Net Losses And Loss Expenses, Current year		1,542,602	1,160,572	1,203,977
Net Losses And Loss Expenses, Prior Year		(221,550)	(243,464)	(233,815)
Amortization of Deferred Acquisition Costs		460,483	347,885	319,513
Paid Losses and Loss Expenses		1,185,890	1,133,637	1,158,212
Net Premiums Written		2,369,935	1,950,470	1,934,206
Reinsurance
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Deferred Acquisition Costs		204,137	197,285	172,787
Reserve for Losses and Loss Expenses		2,106,149	2,016,521	1,723,087
Discount if any, Reserve for Losses and Loss Expenses		0	0	0
Unearned Premiums		870,317	886,996	611,740
Net Premiums Earned		1,354,285	1,153,901	1,030,066
Net Investment Income	[1]	0	0	0
Net Losses And Loss Expenses, Current year		781,287	577,704	528,846
Net Losses And Loss Expenses, Prior Year		(144,413)	(161,463)	(153,245)
Amortization of Deferred Acquisition Costs		310,720	267,633	254,145
Paid Losses and Loss Expenses		593,872	507,031	457,636
Net Premiums Written		1,313,681	1,070,097	1,073,800
Insurance
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Deferred Acquisition Costs		72,502	58,216	34,581
Reserve for Losses and Loss Expenses		2,798,989	2,493,894	2,123,772
Discount if any, Reserve for Losses and Loss Expenses		0	0	0
Unearned Premiums		1,124,359	902,152	642,779
Net Premiums Earned		1,009,375	824,552	833,912
Net Investment Income	[1]	0	0	0
Net Losses And Loss Expenses, Current year		761,315	582,868	675,131
Net Losses And Loss Expenses, Prior Year		(77,137)	(82,001)	(80,570)
Amortization of Deferred Acquisition Costs		149,763	80,252	65,368
Paid Losses and Loss Expenses		592,018	626,606	700,576
Net Premiums Written		$ 1,056,254	$ 880,373	$ 860,406
[1]	Because the Company does not manage its assets by segment, investment income is not allocated to the individual segments.