Validus 10-Q 2 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 31, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	VALIDUS HOLDINGS LTD
Entity Central Index Key	1,348,259
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		79,461,813

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets
Fixed maturity investments trading, at fair value (amortized cost: 2017—$5,421,546; 2016—$5,584,599)	$ 5,419,966	$ 5,543,030
Short-term investments trading, at fair value (amortized cost: 2017—$2,992,939; 2016—$2,796,358)	2,993,246	2,796,170
Other investments, at fair value (cost: 2017—$439,991; 2016—$380,130)	471,300	405,712
Investments in investment affiliates, equity method (cost: 2017—$60,228; 2016—$84,840)	92,079	100,431
Cash and cash equivalents	965,630	419,976
Restricted cash	89,403	70,956
Total investments and cash	10,031,624	9,336,275
Premiums receivable	1,569,374	725,390
Deferred acquisition costs	258,078	209,227
Prepaid reinsurance premiums	207,618	77,996
Securities lending collateral	2,115	9,779
Loss reserves recoverable	1,335,016	430,421
Paid losses recoverable	77,730	35,247
Income taxes recoverable	9,704	4,870
Deferred tax asset	52,228	43,529
Receivable for investments sold	37,493	3,901
Intangible assets	173,398	115,592
Goodwill	227,701	196,758
Accrued investment income	27,976	26,488
Other assets	591,185	134,282
Total assets	14,601,240	11,349,755
Liabilities
Reserve for losses and loss expenses	4,935,637	2,995,195
Unearned premiums	1,526,465	1,076,049
Reinsurance balances payable	527,881	54,781
Securities lending payable	2,581	10,245
Deferred tax liability	4,198	3,331
Payable for investments purchased	84,431	29,447
Accounts payable and accrued expenses	478,892	587,648
Notes payable to AlphaCat investors	1,107,618	278,202
Senior notes payable	245,513	245,362
Debentures payable	538,910	537,226
Total liabilities	9,452,126	5,817,486
Commitments and contingent liabilities
Redeemable noncontrolling interests	1,133,880	1,528,001
Shareholders' equity
Preferred shares (Issued and Outstanding: 2017—16,000; 2016—6,000)	400,000	150,000
Common shares (Issued: 2017—161,956,886; 2016—161,279,976; Outstanding: 2017—79,457,253; 2016—79,132,252)	28,342	28,224
Treasury shares (2017—82,499,633; 2016—82,147,724)	(14,437)	(14,376)
Additional paid-in capital	812,266	821,023
Accumulated other comprehensive loss	(18,430)	(23,216)
Retained earnings	2,728,546	2,876,636
Total shareholders' equity available to Validus	3,936,287	3,838,291
Noncontrolling interests	78,947	165,977
Total shareholders' equity	4,015,234	4,004,268
Total liabilities, noncontrolling interests and shareholders’ equity	$ 14,601,240	$ 11,349,755

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Assets
Fixed maturities, at amortized cost or cost	$ 5,421,546	$ 5,584,599
Short-term investments, at amortized cost or cost	2,992,939	2,796,358
Other investments, at amortized cost or cost	439,991	380,130
Investments in and advance to affiliates, subsidiaries, associates, and joint ventures, at cost	$ 60,228	$ 84,840
Preferred shares - Shareholders' Equity
Preferred shares, shares issued	16,000	6,000	6,000	0
Preferred shares, shares outstanding	16,000	6,000	6,000	0
Common Shares - Shareholders' Equity
Common shares, shares issued	161,956,886	161,279,976	161,273,353	160,570,772
Common shares, shares outstanding	79,457,253	79,132,252	79,443,030
Treasury shares, common shares	82,499,633	82,147,724	81,830,323

Consolidated Statements of Inco

Consolidated Statements of Income and Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues
Gross premiums written	$ 523,856	$ 372,418	$ 2,507,615	$ 2,309,251
Reinsurance premiums ceded	(116,860)	(45,006)	(373,188)	(249,070)
Net premiums written	406,996	327,412	2,134,427	2,060,181
Change in unearned premiums	316,212	236,363	(204,816)	(351,415)
Net premiums earned	723,208	563,775	1,929,611	1,708,766
Net investment income	44,458	43,514	128,913	112,232
Net realized gains on investments	906	4,397	2,016	6,537
Change in net unrealized (losses) gains on investments	(5,197)	5,459	24,472	84,331
Income (loss) from investment affiliates	1,011	453	15,665	(4,249)
Other insurance related income and other income (loss)	3,571	(610)	6,240	1,627
Foreign exchange (losses) gains	(1,404)	(766)	(7,164)	11,765
Total revenues	766,553	616,222	2,099,753	1,921,009
Expenses
Losses and loss expenses	1,254,602	258,394	1,820,336	789,971
Policy acquisition costs	115,590	113,434	344,486	328,593
General and administrative expenses	70,342	82,443	254,615	258,339
Share compensation expenses	9,443	10,501	30,080	32,465
Finance expenses	14,523	14,521	42,675	43,890
Transaction expenses	0	0	4,427	0
Total expenses	1,464,500	479,293	2,496,619	1,453,258
(Loss) income before taxes, (loss) from operating affiliate and loss (income) attributable to AlphaCat investors	(697,947)	136,929	(396,866)	467,751
Tax benefit (expense)	2,632	(1,830)	7,168	(1,418)
(Loss) from operating affiliate	0	0	0	(23)
Loss (income) attributable to AlphaCat investors	74,130	(5,564)	54,797	(16,278)
Net (loss) income	(621,185)	129,535	(334,901)	450,032
Net (income) attributable to noncontrolling interests	376,366	(37,439)	290,144	(96,163)
Net (loss) income (attributable) available to Validus	(244,819)	92,096	(44,757)	353,869
Dividends on preferred shares	(5,627)	(2,252)	(10,033)	(2,252)
Net (loss) income (attributable) available to Validus common shareholders	(250,446)	89,844	(54,790)	351,617
Comprehensive (loss) income
Net (loss) income	(621,185)	129,535	(334,901)	450,032
Other comprehensive income (loss)
Change in foreign currency translation adjustments	1,481	(1,370)	3,567	(6,685)
Change in minimum pension liability, net of tax	0	(1,101)	1,252	(705)
Change in fair value of cash flow hedge	13	(439)	(33)	(1,133)
Other comprehensive income (loss)	1,494	(2,910)	4,786	(8,523)
Comprehensive loss (income) attributable to noncontrolling interests	376,366	(37,439)	290,144	(96,163)
Comprehensive (loss) income (attributable) available to Validus	$ (243,325)	$ 89,186	$ (39,971)	$ 345,346
Earnings per common share
Basic (loss) earnings per share (attributable) available to Validus common shareholders	$ (3.17)	$ 1.12	$ (0.69)	$ 4.31
(Loss) earnings per diluted share (attributable) available to Validus common shareholders	(3.17)	1.11	(0.69)	4.24
Cash dividends declared per common share	$ 0.38	$ 0.35	$ 1.14	$ 1.05
Weighted average number of common shares and common share equivalents outstanding:
Basic (in shares)	78,994,335	80,134,394	79,132,856	81,635,496
Diluted (in shares)	78,994,335	81,244,556	79,132,856	82,938,624

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred shares	Common shares	Treasury shares	Additional paid-in capital	Accumulated other comprehensive loss	Retained earnings
Balance - Beginning of period at Dec. 31, 2015		$ 0	$ 28,100	$ (13,592)	$ 1,002,980	$ (12,569)	$ 2,634,056
Preferred shares issued		150,000
Common shares issued (redeemed), net			123		(7,754)
Offering expenses on preferred shares					(5,148)
Repurchase of common shares				(728)	(195,287)
Share compensation expenses					32,465
Other comprehensive (loss) income	$ (8,523)					(8,523)
Net (loss) income	450,032						450,032
Net (income) attributable to noncontrolling interests	(96,163)						(96,163)
Dividends on preferred shares							(2,252)
Dividends on common shares							(88,120)
Balance - End of period at Sep. 30, 2016	3,867,620	150,000	28,223	(14,320)	827,256	(21,092)	2,897,553
Noncontrolling interests at Sep. 30, 2016	222,996
Total shareholders' equity at Sep. 30, 2016	4,090,616					(21,092)
Other comprehensive (loss) income	(2,910)
Net (loss) income	129,535
Net (income) attributable to noncontrolling interests	(37,439)
Balance - End of period at Sep. 30, 2016	3,867,620	150,000	28,223	(14,320)	827,256	(21,092)	2,897,553
Noncontrolling interests at Sep. 30, 2016	222,996
Total shareholders' equity at Sep. 30, 2016	4,090,616					(21,092)
Balance - Beginning of period at Dec. 31, 2016	3,838,291	150,000	28,224	(14,376)	821,023	(23,216)	2,876,636
Preferred shares issued		250,000
Common shares issued (redeemed), net			118		(12,241)
Offering expenses on preferred shares					(8,314)
Repurchase of common shares				(61)	(18,282)
Share compensation expenses					30,080
Other comprehensive (loss) income	4,786					4,786
Net (loss) income	(334,901)						(334,901)
Net (income) attributable to noncontrolling interests	290,144						290,144
Dividends on preferred shares							(10,033)
Dividends on common shares							(93,300)
Balance - End of period at Sep. 30, 2017	3,936,287	400,000	28,342	(14,437)	812,266	(18,430)	2,728,546
Noncontrolling interests at Sep. 30, 2017	78,947
Total shareholders' equity at Sep. 30, 2017	4,015,234					(18,430)
Other comprehensive (loss) income	1,494
Net (loss) income	(621,185)
Net (income) attributable to noncontrolling interests	376,366
Balance - End of period at Sep. 30, 2017	3,936,287	$ 400,000	$ 28,342	$ (14,437)	$ 812,266	(18,430)	$ 2,728,546
Noncontrolling interests at Sep. 30, 2017	78,947
Total shareholders' equity at Sep. 30, 2017	$ 4,015,234					$ (18,430)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows provided by (used in) operating activities
Net (loss) income	$ (334,901)	$ 450,032
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Share compensation expenses	30,080	32,465
Loss on deconsolidation of AlphaCat ILS fund	402	0
Amortization of discount on senior notes	81	81
(Income) loss from investment affiliates	(15,665)	4,249
Net realized and change in net unrealized gains on investments	(26,488)	(90,868)
Amortization of intangible assets	6,115	4,248
Loss from operating affiliate	0	23
Foreign exchange gains included in net income	(14,179)	(4,585)
Amortization of premium on fixed maturities	11,178	13,381
Change in:
Premiums receivable	(275,782)	(288,048)
Deferred acquisition costs	(52,967)	(68,920)
Prepaid reinsurance premiums	97,535	(41,813)
Loss reserves recoverable	(847,186)	(97,742)
Paid losses recoverable	(24,598)	(13,165)
Reserve for losses and loss expenses	1,822,992	66,561
Unearned premiums	43,767	393,228
Reinsurance balances payable	177,798	2,726
Other operational balance sheet items, net	(294,300)	(107,257)
Net cash provided by operating activities	303,882	254,596
Cash flows provided by (used in) investing activities
Proceeds on sales of fixed maturity investments	2,533,122	2,047,496
Proceeds on maturities of fixed maturity investments	356,073	256,082
Purchases of fixed maturity investments	(2,746,360)	(2,317,674)
Purchases of short-term investments, net	(188,928)	(540,102)
Purchases of other investments, net	(53,617)	(53,627)
Decrease (increase) in securities lending collateral	7,664	(5,766)
Redemption from operating affiliates	0	369
Distributions from (investments in) investment affiliates, net	24,017	(16,307)
Increase in restricted cash	(18,447)	(39,778)
Purchase of subsidiary, net of cash acquired	183,923	0
Net cash used in investing activities	(270,399)	(669,307)
Cash flows provided by (used in) financing activities
Net proceeds on issuance of notes payable to AlphaCat investors	310,548	296,527
Net proceeds on issuance of preferred shares	241,686	144,852
Redemption of common shares, net	(12,123)	(7,631)
Purchases of common shares under share repurchase program	(18,343)	(196,015)
Dividends paid on preferred shares	(10,033)	(2,252)
Dividends paid on common shares	(93,615)	(87,901)
(Decrease) increase in securities lending payable	(7,664)	5,766
Third party investment in redeemable noncontrolling interests	237,199	381,950
Third party redemption of redeemable noncontrolling interests	(157,534)	(17,284)
Third party investment in noncontrolling interests	258,300	171,674
Third party distributions of noncontrolling interests	(197,250)	(127,103)
Third party subscriptions deployed in AlphaCat Funds and Sidecars	(57,452)	(412,736)
Net cash provided by financing activities	493,719	149,847
Effect of foreign currency rate changes on cash and cash equivalents	18,452	(14,253)
Net increase (decrease) in cash and cash equivalents	545,654	(279,117)
Cash and cash equivalents - beginning of period	419,976	723,109
Cash and cash equivalents - end of period	965,630	443,992
Supplemental disclosure of cash flow information:
Taxes paid during the period	2,810	5,914
Interest paid during the period	$ 46,388	$ 46,072

Basis of preparation and consol

Basis of preparation and consolidation	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of presentation and consolidation	Basis of preparation and consolidation These unaudited Consolidated Financial Statements (the “Consolidated Financial Statements”) have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 in Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In addition, the year-end balance sheet data was derived from audited financial statements but does not include all disclosures required by U.S. GAAP. This Quarterly Report on Form 10-Q should be read in conjunction with the financial statements and related notes included in Validus Holdings, Ltd.’s (the “Company”) Annual Report on Form 10-K for the year ended December 31, 2016 , as filed with the U.S. Securities and Exchange Commission (the “SEC”). The Company consolidates in these Consolidated Financial Statements the results of operations and financial position of all voting interest entities (“VOE”) in which the Company has a controlling financial interest and all variable interest entities (“VIE”) in which the Company is considered to be the primary beneficiary. The consolidation assessment, including the determination as to whether an entity qualifies as a VIE or VOE, depends on the facts and circumstances surrounding each entity. In the opinion of management, these unaudited Consolidated Financial Statements reflect all adjustments (including normal recurring adjustments) considered necessary for a fair statement of the Company’s financial position and results of operations as at the end of and for the periods presented. All significant intercompany accounts and transactions have been eliminated. The results of operations for any interim period are not necessarily indicative of the results for a full year. The preparation of these financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported 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. While management believes that the amounts included in the Consolidated Financial Statements reflect its best estimates and assumptions, actual results could differ materially from those estimates. The Company’s principal estimates include: • reserve for losses and loss expenses; • premium estimates for business written on a line slip or proportional basis; • the valuation of goodwill and intangible assets; • reinsurance recoverable balances including the provision for uncollectible amounts; and • investment valuation of financial assets. The term “ASC” used in these notes refers to Accounting Standard Codification issued by the United States Financial Accounting Standards Board (the “FASB”).

Recent accounting pronouncement

Recent accounting pronouncements	9 Months Ended
	Sep. 30, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent accounting pronouncements	Recent accounting pronouncements Recently issued accounting standards not yet adopted In August 2017, the FASB issued ASU 2017-12, “Derivatives and Hedging (Topic 815).” This ASU is directed at targeted improvements to accounting for hedging activities. This ASU is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The Company is currently evaluating the impact of this guidance on the Company’s Consolidated Financial Statements.

Business combination

Business combination	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Business combination	Business combination On May 1, 2017, Western World Insurance Group, Inc. (“Western World”), a wholly owned subsidiary of the Company acquired all of the outstanding capital stock of Crop Risk Services (“CRS”) for an aggregate purchase price of $185,576 in cash. CRS is a primary crop insurance managing general agent (“MGA”) based in Decatur, Illinois with 1,170 agents across 36 states. CRS does not have insurance licenses of its own, but acts solely as an MGA in that it can produce business for any properly licensed entity on a commission basis. Concurrent with closing of the transaction, Stratford Insurance Company (“Stratford”), a wholly–owned subsidiary of Western World, was granted the required licenses to write crop insurance in the United States and executed several agreements to transfer the related agriculture book of business to Stratford. The CRS acquisition was undertaken to expand the Company’s presence in U.S. primary specialty lines. For segmental reporting purposes, the results of CRS’ operations, including the related agricultural book of business have been included within the Western World segment in the Consolidated Financial Statements from the date of acquisition. On closing, the Company recorded intangible assets totaling $63,921 for Distribution Channels, Brand Name and Technology. Distribution Channels and Brand Name were estimated to have finite useful economic lives of ten years on acquisition and are being amortized on a straight line basis over such period. Technology was estimated to have a finite useful economic life of two years on acquisition and is being amortized on a straight line basis over such a period. The purchase price was allocated to the acquired assets and liabilities of CRS based on estimated fair values on May 1, 2017, the date the transaction closed, as detailed below. The Company recognized goodwill of $30,943 primarily attributable to CRS’s assembled workforce and synergies expected to result upon the integration of CRS and its related book of business into the Company’s operations. The estimates of fair values for tangible assets acquired and liabilities assumed were determined by management based on various market and income analyses. The Company estimated the fair values of intangible assets acquired based on variations of the income and cost approaches. Significant judgment was required to arrive at these estimates of fair value and changes to assumptions used could have led to materially different results. The purchase of CRS was a taxable transaction and as such, goodwill and intangibles recorded at closing will be deductible for income tax purposes. The Company has recognized and recorded a deferred tax asset of $6,443 which results from the excess of tax-deductible goodwill over book value goodwill as recognized in the purchase price allocation. The fair value of net assets acquired, including GAAP adjustments, are summarized as follows: Total purchase price $ 185,576 Assets acquired Cash and cash equivalents $ 1,653 Premiums receivable 564,453 Prepaid reinsurance premiums 227,157 Other assets 157,146 Assets acquired 950,409 Liabilities acquired Reinsurance balances payable $ 294,201 Unearned premiums 406,649 Net loss reserves 42,575 Other liabilities 122,715 Liabilities acquired 866,140 Excess purchase price $ 101,307 Goodwill and other intangible assets acquired Intangible asset - Distribution channels $ 52,898 Intangible asset - Brand name 9,568 Intangible asset - Technology 1,455 Total intangible assets 63,921 Goodwill 30,943 Deferred tax arising on Goodwill 6,443 Total goodwill and intangible assets $ 101,307 The Company also incurred transaction expenses related to the CRS acquisition of $4,427 . Transaction expenses included legal, financial advisory and audit related services. The following tables reconcile the carrying amount of goodwill and intangible assets from December 31, 2016 to September 30, 2017 : Goodwill Nine Months Ended September 30, 2017 Talbot Western World Total Balance at December 31, 2016 $ 20,393 $ 176,365 $ 196,758 Additions — 30,943 30,943 Balance at September 30, 2017 $ 20,393 $ 207,308 $ 227,701 Intangible assets Nine Months Ended September 30, 2017 Talbot Western World Total Balance at December 31, 2016 $ 93,924 $ 21,668 $ 115,592 Additions — 63,921 63,921 Amortization (2,081 ) (4,034 ) (6,115 ) Balance at September 30, 2017 $ 91,843 $ 81,555 $ 173,398 Intangible assets Nine Months Ended September 30, 2017 With a Finite Life With an Indefinite Life Total Balance at December 31, 2016 $ 11,424 $ 104,168 $ 115,592 Additions 63,921 — 63,921 Amortization (6,115 ) — (6,115 ) Balance at September 30, 2017 $ 69,230 $ 104,168 $ 173,398 Operating results of CRS have been included in the Consolidated Financial Statements from the May 1, 2017 acquisition date. The following selected unaudited information has been provided to present a summary of the results of CRS that have been included in the Consolidated Financial Statements for the three and nine months ended September 30, 2017 . Three Months Ended September 30, 2017 Nine Months Ended September 30, 2017 Net premiums written $ 32,852 $ 39,840 Net premiums earned $ 98,757 $ 148,801 Total underwriting deductions $ 84,826 $ 129,606 Underwriting income, before general and administrative expenses $ 13,931 $ 19,195

Investments

Investments	9 Months Ended
	Sep. 30, 2017
Investments [Abstract]
Investments	Investments Managed investments represent assets governed by the Company’s investment policy statement (“IPS”) whereas, non-managed investments represent assets held in support of consolidated AlphaCat VIEs which are not governed by the Company’s IPS. Refer to Note 6 , “Variable interest entities,” for further details. The Company classifies its fixed maturity and short-term investments as trading and accounts for its other investments in accordance with ASC Topic 825 “ Financial Instruments. ” As such, all investments are carried at fair value with interest and dividend income and realized and unrealized gains and losses included in net income for the period. The amortized cost (or cost) and fair value of the Company’s investments as at September 30, 2017 and December 31, 2016 were as follows: September 30, 2017 December 31, 2016 Amortized Amortized Fair Value Managed investments U.S. government and government agency $ 598,607 $ 595,694 $ 809,392 $ 804,126 Non-U.S. government and government agency 288,296 290,538 245,651 240,791 U.S. states, municipalities and political subdivisions 205,880 206,667 271,742 271,830 Agency residential mortgage-backed securities 830,542 828,400 684,490 679,595 Non-agency residential mortgage-backed securities 38,806 38,993 15,858 15,477 U.S. corporate 1,457,073 1,466,739 1,540,036 1,534,508 Non-U.S. corporate 390,519 392,242 418,520 410,227 Bank loans 471,855 464,464 579,121 570,399 Asset-backed securities 520,594 522,524 528,563 526,814 Commercial mortgage-backed securities 315,585 314,221 333,740 330,932 Total fixed maturities 5,117,757 5,120,482 5,427,113 5,384,699 Short-term investments 258,339 258,646 228,574 228,386 Other investments Fund of hedge funds — — 1,457 955 Hedge funds 11,292 19,233 11,292 17,381 Private equity investments 88,299 107,230 66,383 82,627 Fixed income investment funds 282,707 285,034 247,967 249,275 Overseas deposits 55,775 55,775 50,106 50,106 Mutual funds 1,918 4,028 2,925 5,368 Total other investments 439,991 471,300 380,130 405,712 Investments in investment affiliates (a) 60,228 92,079 84,840 100,431 Total managed investments $ 5,876,315 $ 5,942,507 $ 6,120,657 $ 6,119,228 Non-managed investments Catastrophe bonds $ 303,789 $ 299,484 $ 157,486 $ 158,331 Short-term investments 2,734,600 2,734,600 2,567,784 2,567,784 Total non-managed investments 3,038,389 3,034,084 2,725,270 2,726,115 Total investments $ 8,914,704 $ 8,976,591 $ 8,845,927 $ 8,845,343 (a) The Company’s investments in investment affiliates have been treated as equity method investments with the corresponding gains and losses recorded in income as “Income (loss) from investment affiliates.” (a) Fixed maturity investments The following table sets forth certain information regarding the investment ratings of the Company’s fixed maturity investments as at September 30, 2017 and December 31, 2016 . September 30, 2017 December 31, 2016 Fair Value % of Total Fair Value % of Total Managed fixed maturities AAA $ 2,349,803 43.3 % $ 2,405,597 43.4 % AA 437,215 8.1 % 538,289 9.7 % A 1,060,849 19.6 % 1,081,949 19.5 % BBB 752,808 13.9 % 740,861 13.4 % Total investment grade managed fixed maturities 4,600,675 84.9 % 4,766,696 86.0 % BB 177,667 3.2 % 213,568 3.9 % B 156,590 2.9 % 177,737 3.2 % CCC 5,286 0.1 % 13,371 0.2 % NR 180,264 3.4 % 213,327 3.8 % Total non-investment grade fixed maturities 519,807 9.6 % 618,003 11.1 % Total managed fixed maturities $ 5,120,482 94.5 % $ 5,384,699 97.1 % Non-managed catastrophe bonds AAA $ 1,650 0.0 % $ — 0.0 % Total investment grade non-managed fixed maturities 1,650 0.0 % — 0.0 % BB 28,031 0.5 % 29,731 0.6 % B 2,755 0.1 % 4,524 0.1 % NR 267,048 4.9 % 124,076 2.2 % Total non-investment grade non-managed fixed maturities 297,834 5.5 % 158,331 2.9 % Total non-managed fixed maturities 299,484 5.5 % 158,331 2.9 % Total fixed maturities $ 5,419,966 100.0 % $ 5,543,030 100.0 % The amortized cost and fair value amounts for the Company’s fixed maturity investments held at September 30, 2017 and December 31, 2016 are shown below by contractual maturity. Actual maturity may differ from contractual maturity because certain borrowers may have the right to call or prepay certain obligations with or without call or prepayment penalties. September 30, 2017 December 31, 2016 Amortized Cost Fair Value Amortized Cost Fair Value Managed fixed maturities Due in one year or less $ 279,069 $ 278,118 $ 350,733 $ 346,161 Due after one year through five years 2,418,737 2,416,963 2,954,856 2,933,146 Due after five years through ten years 534,922 535,538 430,365 426,647 Due after ten years 179,502 185,725 128,508 125,927 3,412,230 3,416,344 3,864,462 3,831,881 Asset-backed and mortgage-backed securities 1,705,527 1,704,138 1,562,651 1,552,818 Total managed fixed maturities $ 5,117,757 $ 5,120,482 $ 5,427,113 $ 5,384,699 Non-managed catastrophe bonds Due in one year or less $ 88,949 $ 88,202 $ 43,664 $ 45,418 Due after one year through five years 209,340 206,117 112,572 111,656 Due after five years through ten years 5,500 5,165 1,250 1,257 Total non-managed fixed maturities 303,789 299,484 157,486 158,331 Total fixed maturities $ 5,421,546 $ 5,419,966 $ 5,584,599 $ 5,543,030 (b) Other investments The following tables set forth certain information regarding the Company’s other investment portfolio as at September 30, 2017 and December 31, 2016 : September 30, 2017 Fair Value Investments with redemption restrictions Investments without redemption restrictions Redemption frequency (a) Redemption notice period (a) Hedge funds 19,233 19,233 — Private equity investments 107,230 107,230 — Fixed income investment funds 285,034 249,999 35,035 Daily Daily to 2 days Overseas deposits 55,775 55,775 — Mutual funds 4,028 — 4,028 Daily Daily Total other investments $ 471,300 $ 432,237 $ 39,063 December 31, 2016 Fair Value Investments with redemption restrictions Investments without redemption restrictions Redemption frequency (a) Redemption notice period (a) Fund of hedge funds $ 955 $ 955 $ — Hedge funds 17,381 17,381 — Private equity investments 82,627 82,627 — Fixed income investment funds 249,275 218,333 30,942 Daily 2 days Overseas deposits 50,106 50,106 — Mutual funds 5,368 — 5,368 Daily Daily Total other investments $ 405,712 $ 369,402 $ 36,310 (a) The redemption frequency and notice periods only apply to investments without redemption restrictions. Other investments include alternative investments in various funds and pooled investment schemes. These alternative investments employ various investment strategies primarily involving, but not limited to, investments in collateralized obligations, fixed income securities, private equities, distressed debt and equity securities. Certain debt-like investments totaling $274,651 are either rated or consist of underlying securities or instruments which carry credit ratings issued by nationally recognized statistical rating organizations. Other equity-like investments totaling $196,649 are unrated given the nature of their underlying assets, such as private equity investments, and as such do not carry credit ratings. Certain securities included in other investments are subject to redemption restrictions and are unable to be redeemed from the funds. Distributions from these funds will be received as the underlying investments of the funds are liquidated. Currently, it is not known to the Company when these underlying assets will be sold by their investment managers; however, it is estimated that the majority of the underlying assets of the investments would liquidate over five to ten years from inception of the funds. In addition, one of the investment funds with a fair value of $195,903 ( December 31, 2016 : $184,749 ), has various lock-up periods of approximately two years or less as at September 30, 2017 and may also impose a redemption gate. A lock-up period refers to the initial amount of time an investor is contractually required to remain invested before having the ability to redeem. Typically, the imposition of a gate delays a portion of the requested redemption, with the remaining portion settled in cash shortly after the redemption date. The underlying investments held in the overseas deposit funds are liquid and will generally trade freely in an open market. However, the Company’s ability to withdraw from the overseas deposit funds is restricted by an annual and quarterly funding and release process for Lloyd’s market participants. The Company’s maximum exposure to any of these alternative investments is limited to the amount invested and any remaining capital commitments. Refer to Note 15 , “ Commitments and contingencies ,” for further details. As at September 30, 2017 , the Company does not have any plans to sell any of the other investments listed above. (c) Investments in investment affiliates Included in the Company’s managed investment portfolio as at September 30, 2017 were investments in Aquiline Financial Services Fund II L.P. (“Aquiline II”), Aquiline Financial Services Fund III L.P. (“Aquiline III”) and Aquiline Technology Growth Fund L.P. (“Aquiline Tech”). Aquiline II and III For further information regarding Aquiline II and III please refer to Note 7(c), “Investments in investment affiliates,” included within the Company’s Annual Report on Form 10-K for the year ended December 31, 2016 . As at September 30, 2017 , the Company’s total unfunded investment commitment to Aquiline II and III was $3,229 and $66,285 , respectively ( December 31, 2016 : $2,040 and $62,031 ). Aquiline Tech On March 20, 2017, the Company entered into a Subscription Agreement (the “Subscription Agreement”) with Aquiline Technology Growth GP Ltd, (the “General Partner”) pursuant to which the Company committed and agreed to purchase limited partnership or other comparable limited liability equity interests in Aquiline Tech, a Cayman Islands exempted limited partnership, with a capital commitment in an amount equal to $20,000 . The limited partnership interests are governed by the terms of an amended and restated exempted limited partnership agreement. As at September 30, 2017 , the unfunded investment commitment to Aquiline Tech was $17,858 . The following table presents a reconciliation of the Company’s beginning and ending investments in investment affiliates for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Investments in investment affiliates, beginning of period $ 103,377 $ 99,278 $ 100,431 $ 87,673 Net capital (distributions) contributions (12,309 ) — (24,017 ) 16,307 Income (loss) from investment affiliates 1,011 453 15,665 (4,249 ) Investments in investment affiliates, end of period $ 92,079 $ 99,731 $ 92,079 $ 99,731 The following table presents the Company’s investments in investment affiliates as at September 30, 2017 and December 31, 2016 : September 30, 2017 Investment at cost Voting ownership % Equity ownership % Carrying value Aquiline II $ 33,349 — % 8.1 % $ 50,695 Aquiline III 24,737 — % 9.0 % 39,530 Aquiline Tech 2,142 — % 10.6 % 1,854 Total investments in investment affiliates $ 60,228 $ 92,079 December 31, 2016 Investment at cost Voting ownership % Equity ownership % Carrying value Aquiline II $ 46,871 — % 8.1 % $ 61,999 Aquiline III 37,969 — % 9.0 % 38,432 Total investments in investment affiliates $ 84,840 $ 100,431 (d) Net investment income Net investment income was derived from the following sources: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Managed investments Fixed maturities and short-term investments $ 30,823 $ 30,572 $ 93,706 $ 89,210 Other investments 7,391 11,768 21,832 20,666 Cash and cash equivalents and restricted cash 1,230 891 2,556 2,136 Securities lending income 3 22 23 39 Total gross investment income 39,447 43,253 118,117 112,051 Investment expenses (2,356 ) (2,182 ) (6,771 ) (6,208 ) Total managed net investment income $ 37,091 $ 41,071 $ 111,346 $ 105,843 Non managed investments Fixed maturities and short-term investments $ 3,941 $ 1,970 $ 11,501 $ 5,242 Restricted cash, cash and cash equivalents 3,426 473 6,066 1,147 Total non-managed net investment income 7,367 2,443 17,567 6,389 Total net investment income $ 44,458 $ 43,514 $ 128,913 $ 112,232 Net investment income from other investments includes distributed and undistributed net income from hedge funds, overseas deposits and certain fixed income investment funds. (e) Net realized and change in net unrealized (losses) gains on investments The following table sets forth an analysis of net realized gains and the change in net unrealized (losses) gains on investments: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Managed fixed maturities, short-term and other investments Gross realized gains $ 5,170 $ 4,544 $ 13,035 $ 11,067 Gross realized (losses) (4,267 ) (464 ) (12,755 ) (5,553 ) Net realized gains on investments 903 4,080 280 5,514 Change in net unrealized gains on investments 941 4,652 31,232 81,782 Total net realized and change in net unrealized gains on managed investments $ 1,844 $ 8,732 $ 31,512 $ 87,296 Non-managed fixed maturities and short-term investments Gross realized gains $ 3 $ 317 $ 1,736 $ 1,032 Gross realized (losses) — — — (9 ) Net realized gains on investments 3 317 1,736 1,023 Change in net unrealized (losses) gains on investments (6,138 ) 807 (6,760 ) 2,549 Total net realized and change in net unrealized (losses) gains on non-managed investments (6,135 ) 1,124 (5,024 ) 3,572 Total net realized and change in net unrealized (losses) gains on total investments $ (4,291 ) $ 9,856 $ 26,488 $ 90,868 (f) Pledged cash and investments As at September 30, 2017 , the Company had $5,433,107 ( December 31, 2016 : $5,173,966 ) of cash and cash equivalents, restricted cash, short-term investments and fixed maturity investments that were pledged during the normal course of business. Of those, $5,368,025 were held in trust ( December 31, 2016 : $5,068,092 ). Pledged assets are generally for the benefit of the Company’s cedants and policyholders, to support AlphaCat’s fully collateralized reinsurance transactions and to facilitate the accreditation of Validus Reinsurance, Ltd., Validus Reinsurance (Switzerland) Ltd. (“Validus Re Swiss”) and Talbot as an alien Insurer/Reinsurer by certain regulators. In addition, the Company has pledged cash and investments as collateral under the Company’s credit facilities in the total amount of $265,089 ( December 31, 2016 : $442,184 ). For further details on the credit facilities, please refer to Note 13 , “ Debt and financing arrangements .”

Fair value measurements

Fair value measurements	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair value measurements	Fair value measurements (a) Classification within the fair value hierarchy Fair value is defined as the price to sell an asset or transfer a liability in an orderly transaction between market participants. Under U.S. GAAP, a company must determine the appropriate level in the fair value hierarchy for each fair value measurement. The fair value hierarchy prioritizes the inputs, which refer broadly to assumptions market participants would use in pricing an asset or liability, into three levels. It gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The level in the fair value hierarchy within which a fair value measurement in its entirety falls is determined based on the lowest level input that is significant to the fair value measurement in its entirety. The three levels of the fair value hierarchy are described below: Level 1 - Fair values are measured based on unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access. Level 2 - Fair values are measured based on quoted prices in active markets for similar assets or liabilities, quoted prices for identical assets or liabilities in inactive markets, or for which significant inputs are observable (e.g., interest rates, yield curves, prepayment speeds, default rates, loss severities, etc.) or can be corroborated by observable market data. Level 3 - Fair values are measured based on inputs that are unobservable and significant to the overall fair value measurement. The unobservable inputs reflect the Company’s own judgments about assumptions where there is little, if any, market activity for that asset or liability that market participants might use. The availability of observable inputs can vary from financial instrument to financial instrument and is affected by a wide variety of factors including, for example, the type of financial instrument, whether the financial instrument is new and not yet established in the marketplace, and other characteristics particular to the instrument. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires significantly more judgment. Accordingly, the degree of judgment exercised by management in determining fair value is greatest for instruments categorized in Level 3. In periods of market dislocation, the observability of prices and inputs may be reduced for many instruments. This may lead the Company to change the selection of our valuation technique (for example, from market to cash flow approach) or to use multiple valuation techniques to estimate the fair value of a financial instrument. These circumstances could cause an instrument to be reclassified between levels within the fair value hierarchy. At September 30, 2017 , the Company’s investments were allocated between Levels 1, 2 and 3 as follows: Level 1 Level 2 Level 3 Fair value based on NAV practical expedient (a) Total Managed investments U.S. government and government agency $ — $ 595,694 $ — $ — $ 595,694 Non-U.S. government and government agency — 290,538 — — 290,538 U.S. states, municipalities and political subdivisions — 206,667 — — 206,667 Agency residential mortgage-backed securities — 828,400 — — 828,400 Non-agency residential mortgage-backed securities — 38,993 — — 38,993 U.S. corporate — 1,466,739 — — 1,466,739 Non-U.S. corporate — 392,242 — — 392,242 Bank loans — 240,563 223,901 — 464,464 Asset-backed securities — 486,537 35,987 — 522,524 Commercial mortgage-backed securities — 314,221 — — 314,221 Total fixed maturities — 4,860,594 259,888 — 5,120,482 Short-term investments 251,578 7,068 — — 258,646 Other investments Hedge funds — — — 19,233 19,233 Private equity investments — — — 107,230 107,230 Fixed income investment funds — 35,145 16,886 233,003 285,034 Overseas deposits — — — 55,775 55,775 Mutual funds — 4,028 — — 4,028 Total other investments — 39,173 16,886 415,241 471,300 Investments in investment affiliates (b) — — — — 92,079 Total managed investments $ 251,578 $ 4,906,835 $ 276,774 $ 415,241 $ 5,942,507 Non-managed investments Catastrophe bonds $ — $ 230,775 $ 68,709 $ — $ 299,484 Short-term investments 2,734,600 — — — 2,734,600 Total non-managed investments 2,734,600 230,775 68,709 — 3,034,084 Total investments $ 2,986,178 $ 5,137,610 $ 345,483 $ 415,241 $ 8,976,591 (a) In accordance with ASC Topic 820 “Fair Value Measurements,” investments measured at fair value using the net asset value (“NAV”) per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. (b) In accordance with ASC Topic 825 “Financial Instruments,” the Company’s investments in investment affiliates have not been classified in the fair value hierarchy. At December 31, 2016 , the Company’s investments were allocated between Levels 1, 2 and 3 as follows: Level 1 Level 2 Level 3 Fair value based on NAV practical expedient (a) Total Managed investments U.S. government and government agency $ — $ 804,126 $ — $ — $ 804,126 Non-U.S. government and government agency — 240,791 — — 240,791 U.S. states, municipalities and political subdivisions — 271,830 — — 271,830 Agency residential mortgage-backed securities — 679,595 — — 679,595 Non-agency residential mortgage-backed securities — 15,477 — — 15,477 U.S. corporate — 1,534,508 — — 1,534,508 Non-U.S. corporate — 410,227 — — 410,227 Bank loans — 323,903 246,496 — 570,399 Asset-backed securities — 502,883 23,931 — 526,814 Commercial mortgage-backed securities — 330,932 — — 330,932 Total fixed maturities — 5,114,272 270,427 — 5,384,699 Short-term investments 209,651 18,735 — — 228,386 Other investments Fund of hedge funds — — — 955 955 Hedge funds — — — 17,381 17,381 Private equity investments — — — 82,627 82,627 Fixed income investment funds — 30,941 12,168 206,166 249,275 Overseas deposits — — — 50,106 50,106 Mutual funds — 5,368 — — 5,368 Total other investments — 36,309 12,168 357,235 405,712 Investments in investment affiliates (b) — — — — 100,431 Total managed investments $ 209,651 $ 5,169,316 $ 282,595 $ 357,235 $ 6,119,228 Non-managed investments Catastrophe bonds $ — $ 109,956 $ 48,375 $ — $ 158,331 Short-term investments 2,567,784 — — — 2,567,784 Total non-managed investments 2,567,784 109,956 48,375 — 2,726,115 Total investments $ 2,777,435 $ 5,279,272 $ 330,970 $ 357,235 $ 8,845,343 (a) In accordance with ASC Topic 820 “Fair Value Measurements,” investments measured at fair value using the net asset value (“NAV”) per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. (b) In accordance with ASC Topic 825 “Financial Instruments,” the Company’s investments in investment affiliates have not been classified in the fair value hierarchy. At September 30, 2017 , managed Level 3 investments totaled $276,774 (December 31, 2016 : $282,595 ), representing 4.7% (December 31, 2016 : 4.6% ) of total managed investments. (b) Valuation techniques There have been no material changes in the Company’s valuation techniques during the period, or periods, represented by these Consolidated Financial Statements. The following methods and assumptions were used in estimating the fair value of each class of financial instrument recorded in the Consolidated Balance Sheets. Fixed maturity investments In general, valuation of the Company’s fixed maturity investment portfolio is provided by pricing services, such as index providers and pricing vendors, as well as broker quotations. The pricing vendors provide valuations for a high volume of liquid securities that are actively traded. For securities that do not trade on an exchange, the pricing services generally utilize market data and other observable inputs in matrix pricing models to determine month end prices. Prices are generally verified using third party data. Securities which are priced by an index provider are generally included in the index. In general, broker-dealers value securities through their trading desks based on observable inputs. The methodologies include mapping securities based on trade data, bids or offers, observed spreads, and performance on newly issued securities. Broker-dealers also determine valuations by observing secondary trading of similar securities. Prices obtained from broker quotations are considered non-binding, however they are based on observable inputs and by observing secondary trading of similar securities obtained from active, non-distressed markets. The Company considers these Level 2 inputs as they are corroborated with other market observable inputs. The techniques generally used to determine the fair value of the Company’s fixed maturity investments are detailed below by asset class. U.S. government and government agency U.S. government and government agency securities consist primarily of debt securities issued by the U.S. Treasury and mortgage pass-through agencies such as the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation and the Government National Mortgage Association. Fixed maturity investments included in U.S. government and government agency securities are primarily priced by pricing services. When evaluating these securities, the pricing services gather information from market sources and integrate other observations from markets and sector news. Evaluations are updated by obtaining broker dealer quotes and other market information including actual trade volumes, when available. The fair value of each security is individually computed using analytical models which incorporate option adjusted spreads and other daily interest rate data. As the significant inputs used to price these securities are observable, the fair value of these investments are classified as Level 2. Non-U.S. government and government agency Non-U.S. government and government agency securities consist of debt securities issued by non-U.S. governments and their agencies along with supranational organizations (also known as sovereign debt securities). Securities held in these sectors are primarily priced by pricing services who employ proprietary discounted cash flow models to value the securities. Key quantitative inputs for these models are daily observed benchmark curves for treasury, swap and high issuance credits. The pricing services then apply a credit spread for each security which is developed by in-depth and real time market analysis. For securities in which trade volume is low, the pricing services utilize data from more frequently traded securities with similar attributes. These models may also be supplemented by daily market and credit research for international markets. As the significant inputs used to price these securities are observable, the fair value of these investments are classified as Level 2. U.S. states, municipalities and political subdivisions The Company’s U.S. states, municipalities and political subdivisions portfolio contains debt securities issued by U.S. domiciled state and municipal entities. These securities are generally priced by independent pricing services using the techniques described for U.S. government and government agency securities described above. As the significant inputs used to price these securities are observable, the fair value of these investments are classified as Level 2. Agency residential mortgage-backed securities The Company’s agency residential mortgage-backed investments are primarily priced by pricing services using a mortgage pool specific model which utilizes daily inputs from the active to be announced market which is very liquid, as well as the U.S. treasury market. The model also utilizes additional information, such as the weighted average maturity, weighted average coupon and other available pool level data which is provided by the sponsoring agency. Valuations are also corroborated with daily active market quotes. As the significant inputs used to price these securities are observable, the fair value of these investments are classified as Level 2. Non-agency residential mortgage-backed securities The Company’s non-agency mortgage-backed investments include non-agency prime residential mortgage-backed fixed maturity investments. The Company has no fixed maturity investments classified as sub-prime held in its fixed maturity investments portfolio. Securities held in these sectors are primarily priced by pricing services using an option adjusted spread model or other relevant models, which principally utilize inputs including benchmark yields, available trade information or broker quotes, and issuer spreads. The pricing services also review collateral prepayment speeds, loss severity and delinquencies among other collateral performance indicators for the securities valuation, when applicable. As the significant inputs used to price these securities are observable, the fair value of these investments are classified as Level 2. U.S. corporate U.S. corporate debt securities consist primarily of investment-grade debt of a wide variety of U.S. corporate issuers and industries. The Company’s corporate fixed maturity investments are primarily priced by pricing services. When evaluating these securities, the pricing services gather information from market sources regarding the issuer of the security and obtain credit data, as well as other observations, from markets and sector news. Evaluations are updated by obtaining broker dealer quotes and other market information including actual trade volumes, when available. The pricing services also consider the specific terms and conditions of the securities, including any specific features which may influence risk. In certain instances, securities are individually evaluated using a spread which is added to the U.S. treasury curve or a security specific swap curve as appropriate. As the significant inputs used to price these securities are observable, the fair value of these investments are classified as Level 2. Non-U.S. corporate Non-U.S. corporate debt securities consist primarily of investment-grade debt of a wide variety of non-U.S. corporate issuers and industries. The Company’s non-U.S. corporate fixed maturity investments are primarily priced by pricing services. When evaluating these securities, the pricing services gather information from market sources regarding the issuer of the security and obtain credit data, as well as other observations, from markets and sector news. Evaluations are updated by obtaining broker dealer quotes and other market information including actual trade volumes, when available. The pricing services also consider the specific terms and conditions of the securities, including any specific features which may influence risk. As the significant inputs used to price these securities are observable, the fair value of these investments are classified as Level 2. Bank loans The Company’s bank loan investments consist primarily of below-investment-grade debt of a wide variety of corporate issuers and industries. The Company’s bank loans are primarily priced by pricing services. When evaluating these securities, the pricing services gather information from market sources regarding the issuer of the security and obtain credit data, as well as other observations, from markets and sector news. Evaluations are updated by obtaining broker dealer quotes and other market information including actual trade volumes, when available. The pricing services also consider the specific terms and conditions of the securities, including any specific features which may influence risk. As the significant inputs used to price these securities are observable, the fair value of these investments are classified as Level 2. Also, included in the bank loan portfolio is a collection of loan participations held through an intermediary. A third party pricing service provides monthly valuation reports for each loan and participation using a combination of quotations from loan pricing services, leveraged loan indices or market price quotes obtained directly from the intermediary. Significant unobservable inputs used to price these securities include credit spreads and default rates; therefore, the fair value of these investments are classified as Level 3. Asset-backed securities Asset backed securities include mostly investment-grade debt securities backed by pools of loans with a variety of underlying collateral, including automobile loan receivables, student loans, credit card receivables, and collateralized loan obligations originated by a variety of financial institutions. Securities held in these sectors are primarily priced by pricing services. The pricing services apply dealer quotes and other available trade information such as bids and offers, prepayment speeds which may be adjusted for the underlying collateral or current price data, the U.S. treasury curve and swap curve as well as cash settlement. The pricing services determine the expected cash flows for each security held in this sector using historical prepayment and default projections for the underlying collateral and current market data. In addition, a spread is applied to the relevant benchmark and used to discount the cash flows noted above to determine the fair value of the securities held in this sector. As the significant inputs used to price these securities are observable, the fair value of these investments are classified as Level 2. Where pricing is unavailable from pricing services, we obtain non-binding quotes from broker-dealers. This is generally the case when there is a low volume of trading activity and current transactions are not orderly. Broker-dealer quotes for which significant observable inputs are unable to be corroborated with market observable information are classified as Level 3. Commercial mortgage-backed securities Commercial mortgage backed securities are investment-grade debt primarily priced by pricing services. The pricing services apply dealer quotes and other available trade information such as bids and offers, prepayment speeds which may be adjusted for the underlying collateral or current price data, the U.S. treasury curve and swap curve as well as cash settlement. The pricing services determine the expected cash flows for each security held in this sector using historical prepayment and default projections for the underlying collateral and current market data. In addition, a spread is applied to the relevant benchmark and used to discount the cash flows noted above to determine the fair value of the securities held in this sector. As the significant inputs used to price these securities are observable, the fair value of these investments are classified as Level 2. Catastrophe bonds Catastrophe bonds are priced based on broker or underwriter bid indications. As the significant inputs used to price these securities are observable, the fair value of these investments are classified as Level 2. To the extent that these indications are based on significant unobservable inputs, the fair value of the relevant bonds will be classified as a Level 3. Short-term investments Short-term investments consist primarily of highly liquid securities, all with maturities of less than one year from the date of purchase. The fair value of the portfolio is generally determined using amortized cost which approximates fair value. As the highly liquid money market-type funds are actively traded, the fair value of these investments are classified as Level 1. To the extent that the remaining securities are not actively traded due to their approaching maturity, the fair value of these investments are classified as Level 2. Other investments Fund of hedge funds During the three months ended June 30, 2017, the Company’s investment in a fund of hedge funds was liquidated. Prior to liquidation, the fund’s administrator provided a monthly reported NAV with a three month delay in its valuation. The fund manager provided an estimate of the fund NAV at year end based on the estimated performance provided from the underlying funds. To determine the reasonableness of the estimated NAV, the Company compared the fund administrator’s NAV to the fund manager’s estimated NAV that incorporates relevant valuation sources. Prior to liquidation, the fair value of these investments were measured using the NAV practical expedient and therefore were not categorized within the fair value hierarchy. Hedge funds The hedge fund’s administrator provides quarterly NAVs with a three month delay in valuation. The fair value of this investment is measured using the NAV practical expedient and therefore has not been categorized within the fair value hierarchy. Private equity investments The private equity funds provide quarterly or semi-annual partnership capital statements with a three or six month delay which are used as a basis for valuation. These private equity investments vary in investment strategies and are not actively traded in any open markets. The fair value of these investments are measured using the NAV practical expedient and therefore have not been categorized within the fair value hierarchy. Fixed income investment funds The Company’s investment funds classified as Level 2 consist of a pooled investment fund. The pooled investment is invested in fixed income securities with high credit ratings and is only open to Lloyd’s Trust Fund participants. The fair value of units in the investment fund is based on the NAV of the fund and is traded on a daily basis. Included in investment funds is a residual equity tranche of a structured credit fund valued using a dynamic yield that calculates an income accrual based on an underlying valuation model with a typical cash flow waterfall structure. Significant unobservable inputs used to price this fund include default rates and prepayment rates; therefore, the fair value of the investment fund is classified as Level 3. The fair value of the Company’s remaining investment funds is based on the NAV of the fund as reported by the independent fund administrator. The fund’s administrators provide a monthly reported NAV with a one or three month delay in their valuation. The fair value of these investments are measured using the NAV practical expedient and therefore have not been categorized within the fair value hierarchy. Overseas deposits The Company’s share of a portfolio of Lloyd’s overseas deposits are managed centrally by Lloyd’s and invested according to local regulatory requirements. The composition of the portfolio varies and the deposits are made across the market. The fair value of the deposits is based on the portfolio level reporting that is provided by Lloyd’s. The fair value of these investments are measured using the NAV practical expedient and therefore have not been categorized within the fair value hierarchy. Mutual funds Mutual funds consist of an investment fund which invests in various quoted investments. The fair value of units in the mutual fund is based on the NAV of the fund as reported by the fund manager. The mutual fund has daily liquidity which allows us to redeem our holdings at the applicable NAV in the near term. As such, the Company has classified this investment as Level 2. (c) Level 3 investments The following table presents a reconciliation of the beginning and ending balances for all investments measured at fair value on a recurring basis using Level 3 inputs during the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, 2017 Bank Loans Catastrophe Bonds Fixed Income Investment Funds Asset Backed Securities Total Level 3 investments, beginning of period $ 224,172 $ 68,025 $ 16,400 $ 35,921 $ 344,518 Purchases 31,312 — — — 31,312 Sales — — — (71 ) (71 ) Settlements (29,796 ) (1,000 ) 486 — (30,310 ) Change in net unrealized (losses) gains (1,787 ) 1,684 — 137 34 Level 3 investments, end of period $ 223,901 $ 68,709 $ 16,886 $ 35,987 $ 345,483 Three Months Ended September 30, 2016 Bank Loans Catastrophe Bonds Asset Backed Securities Total Level 3 investments, beginning of period $ 243,148 $ 37,518 $ 12,383 $ 293,049 Purchases 21,256 — 11,513 32,769 Sales (12,388 ) — — (12,388 ) Change in net unrealized gains 484 517 — 1,001 Level 3 investments, end of period $ 252,500 $ 38,035 $ 23,896 $ 314,431 Nine Months Ended September 30, 2017 Bank Loans Catastrophe Bonds Fixed Income Investment Funds Asset Backed Securities Total Level 3 investments—beginning of period $ 246,496 $ 48,375 $ 12,168 $ 23,931 $ 330,970 Purchases 71,245 66,091 3,432 11,053 151,821 Sales — — — (124 ) (124 ) Settlements (91,799 ) (49,996 ) 1,286 — (140,509 ) Net realized gains — 3,350 — — 3,350 Change in net unrealized (losses) gains (2,041 ) 889 — 1,127 (25 ) Level 3 investments—end of period $ 223,901 $ 68,709 $ 16,886 $ 35,987 $ 345,483 Nine Months Ended September 30, 2016 Bank Loans Catastrophe Bonds Asset Backed Securities Total Level 3 investments—beginning of period $ 232,337 $ 13,500 $ — $ 245,837 Purchases 72,244 23,272 23,896 119,412 Sales (14,777 ) — — (14,777 ) Settlements (34,033 ) (125 ) — (34,158 ) Change in net unrealized (losses) gains (3,271 ) 1,388 — (1,883 ) Level 3 investments—end of period $ 252,500 $ 38,035 $ 23,896 $ 314,431 There have not been any transfers into or out of Level 3 during the three and nine months ended September 30, 2017 or 2016 . (d) Financial instruments not carried at fair value ASC Topic 825 “Financial Instruments” is also applicable to disclosures of financial instruments not carried at fair value, except for certain financial instruments, including insurance contracts and investments in affiliates. The carrying values of cash and cash equivalents, restricted cash, accrued investment income, other assets, net payable for investments purchased and accounts payable and accrued expenses approximated their fair values at September 30, 2017 , due to their respective short maturities. As these financial instruments are not actively traded, their respective fair values are classified within Level 2.

Variable interest entities

Variable interest entities	9 Months Ended
	Sep. 30, 2017
Variable Interest Entities Disclosure [Abstract]
Variable interest entities	Variable interest entities The Company consolidates all VOEs in which it has a controlling financial interest and all VIEs in which it is considered to be the primary beneficiary. The Company’s VIEs are primarily entities in the AlphaCat segment. (a) Consolidated VIEs AlphaCat sidecars Beginning on May 25, 2011, the Company joined with other investors in capitalizing a series of sidecars for the purpose of investing in collateralized reinsurance and retrocessional contracts. Certain of these sidecars deployed their capital through transactions entered into by AlphaCat Reinsurance Ltd. (“AlphaCat Re”). Each of these entities return capital once the risk period expires and all losses have been paid out. The AlphaCat sidecars are VIEs and are consolidated by the Company as the primary beneficiary. The Company’s maximum exposure to any of the sidecars is the amount of capital invested at any given time. AlphaCat ILS funds The AlphaCat ILS funds received third party subscriptions beginning on December 17, 2012 . The Company and third party investors invest in the AlphaCat ILS funds for the purpose of investing in instruments with returns linked to property catastrophe reinsurance, retrocession and ILS contracts. The AlphaCat ILS funds have varying risk profiles and are categorized by the expected loss of the fund. Expected loss represents the average annual loss over the set of simulation scenarios divided by the total limit. Lower risk ILS funds are defined as having a maximum permitted portfolio expected loss of less than 7% , whereas higher risk ILS funds have a maximum permitted portfolio expected loss of greater than 7% . The AlphaCat ILS funds primarily deploy their capital through transactions entered into by AlphaCat Re and AlphaCat Master Fund Ltd. (“AlphaCat Master Fund”). All of the AlphaCat ILS funds are VIEs and were consolidated by the Company as the primary beneficiary through May 31, 2017. However, on June 1, 2017, the Company redeemed its investment in one of the lower risk AlphaCat ILS funds. As a result, the Company was no longer deemed to be the primary beneficiary and therefore this fund was deconsolidated effective June 1, 2017. The deconsolidation resulted in a loss of $402 which is included in the Consolidated Statements of Comprehensive Income as other insurance related income for the nine months ended September 30, 2017 . The Company’s maximum exposure to any of the funds is the amount of capital invested at any given time and any remaining capital commitments. Refer to Note 15 , “Commitments and contingencies,” for further details. AlphaCat Re and AlphaCat Master Fund The Company utilizes AlphaCat Re and AlphaCat Master Fund (collectively the “master funds”), both market facing entities, for the purpose of writing collateralized reinsurance and investing in capital markets products, respectively, on behalf of certain entities within the AlphaCat segment and direct third party investors. AlphaCat Re enters into transactions on behalf of the AlphaCat sidecars and ILS funds (collectively the “feeder funds”) and direct third party investors, whereas AlphaCat Master Fund only enters into transactions on behalf of certain AlphaCat ILS funds. All of the risks and rewards of the underlying transactions are allocated to the feeder funds and direct third party investors using variable funding notes. The master funds are VIEs and are consolidated by the Company as the primary beneficiary. Notes Payable to AlphaCat Investors The master funds issue variable funding notes to the feeder funds, and direct to third party investors, in order to write collateralized reinsurance and invest in capital markets products on their behalf. The Company’s investments in the feeder funds, together with investments made by third parties in the feeder funds and on a direct basis, are provided as consideration for the notes to the master funds. The duration of the underlying collateralized reinsurance contracts and capital market products is typically twelve months ; however, the variable funding notes do not have a stated maturity date or principal amount since repayment is dependent on the settlement and income or loss of the underlying transactions. Therefore, the notes are subsequently redeemed as the underlying transactions are settled. The income or loss generated by the underlying transactions is then transferred to the feeder funds and direct third party investors via the variable funding notes. Any notes issued by the master funds to the consolidated feeder funds are eliminated on consolidation and only variable funding notes issued by AlphaCat Re to direct third party investors and non-consolidated feeder funds remain on the Consolidated Balance Sheets as notes payable to AlphaCat investors with the related income or loss included in the Consolidated Statements of Income and Comprehensive Income as (income) attributable to AlphaCat investors. To the extent that the income has not been returned to the investors, it is included in accounts payable and accrued expenses in the Consolidated Balance Sheets. During 2017 and 2016, one of the AlphaCat ILS funds (the “Fund”) issued both common shares and structured notes to the Company and other third party investors in order to capitalize the fund. The Fund deploys its capital through AlphaCat Re; therefore, the structured notes do not have a stated maturity date or principal amount since repayment is dependent on the settlement and income or loss of the variable funding notes with AlphaCat Re. The structured notes rank senior to the common shares of the Fund and earn an interest rate of 7% (2016: 8% ) per annum, payable on a cumulative basis in arrears. As the Fund is consolidated by the Company, the structured notes issued to the Company are eliminated on consolidation and only the structured notes issued to third party investors remain on the Consolidated Balance Sheets as notes payable to AlphaCat investors with any related interest included in the Consolidated Statements of Income and Comprehensive Income as (income) attributable to AlphaCat investors. To the extent that the accrued interest on the structured notes has not been returned to the investors, it is included in accounts payable and accrued expenses in the Consolidated Balance Sheets. The following tables present a reconciliation of the beginning and ending notes payable to AlphaCat investors for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, 2017 Variable Funding Notes Structured Notes Total Notes payable to AlphaCat investors, beginning of period $ 893,959 $ 172,200 $ 1,066,159 Issuance of notes payable to AlphaCat investors 59,530 — 59,530 Redemption of notes payable to AlphaCat investors (18,627 ) — (18,627 ) Foreign exchange losses 556 — 556 Notes payable to AlphaCat investors, end of period $ 935,418 $ 172,200 $ 1,107,618 Three Months Ended September 30, 2016 Variable Funding Notes Structured Notes Total Notes payable to AlphaCat investors, beginning of period $ 276,656 $ 94,326 $ 370,982 Issuance of notes payable to AlphaCat investors 13,808 — 13,808 Redemption of notes payable to AlphaCat investors (12,028 ) — (12,028 ) Foreign exchange gains (32 ) — (32 ) Notes payable to AlphaCat investors, end of period $ 278,404 $ 94,326 $ 372,730 Nine Months Ended September 30, 2017 Variable Funding Notes Structured Notes Total Notes payable to AlphaCat investors, beginning of period $ 278,202 $ — $ 278,202 Notes payable to AlphaCat investors recognized on deconsolidation of AlphaCat ILS fund 423,269 — 423,269 Issuance of notes payable to AlphaCat investors 601,407 172,200 773,607 Redemption of notes payable to AlphaCat investors (367,733 ) — (367,733 ) Foreign exchange losses 273 — 273 Notes payable to AlphaCat investors, end of period $ 935,418 $ 172,200 $ 1,107,618 Nine Months Ended September 30, 2016 Variable Funding Notes Structured Notes Total Notes payable to AlphaCat investors, beginning of period $ 75,493 $ — $ 75,493 Issuance of notes payable to AlphaCat investors 311,913 94,326 406,239 Redemption of notes payable to AlphaCat investors (109,712 ) — (109,712 ) Foreign exchange losses 710 — 710 Notes payable to AlphaCat investors, end of period $ 278,404 $ 94,326 $ 372,730 As at December 31, 2016 , $1,000 of the structured notes redeemed during the year were payable to AlphaCat investors and included in accounts payable and accrued expenses. The loss attributable to AlphaCat investors for the three and nine months ended September 30, 2017 was $74,130 and $54,797 ( 2016 : income of $5,564 and $16,278 ), with $9,737 included in accounts payable and accrued expenses as at September 30, 2017 (December 31, 2016 : $17,068 ). BetaCat ILS funds The BetaCat ILS funds invest exclusively in catastrophe bonds (principal-at-risk variable rate notes and other event-linked securities, being referred to collectively as “Cat Bonds”) focused on property and casualty risk and issued under Rule 144A of the Securities Act of 1933, as amended, following a passive buy-and-hold investment strategy. Two of the funds are VIEs, one of which is consolidated by the Company as the primary beneficiary. The remaining fund is a VOE and is consolidated by the Company as it owns all of the voting equity interests. The Company’s maximum exposure to any of the funds is the amount of capital invested at any given time. The following table presents the total assets and total liabilities of the Company’s consolidated VIEs, excluding intercompany eliminations, as at September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 Total Assets Total Liabilities Total Assets Total Liabilities AlphaCat sidecars $ 30,598 $ 3,708 $ 40,041 $ 3,206 AlphaCat ILS funds - Lower Risk (a) 1,019,072 234,192 1,498,276 42,457 AlphaCat ILS funds - Higher Risk (a) 947,135 541,466 972,633 381,332 AlphaCat Re and AlphaCat Master Fund 3,427,625 3,427,455 2,510,415 2,510,245 BetaCat ILS funds 144,766 291 82,471 30,663 (a) Lower risk AlphaCat ILS funds have a maximum permitted portfolio expected loss of less than 7%, whereas higher risk AlphaCat ILS funds have a maximum permitted portfolio expected loss of greater than 7%. Expected loss represents the average annual loss over the set of simulation scenarios divided by the total limit. Assets of consolidated VIEs can only be used to settle obligations and liabilities of the consolidated VIEs and do not have recourse to the general credit of the Company. Investments held by these entities are presented separately in Note 4 , “ Investments ,” as non-managed investments. (b) Non-Consolidated VIEs The Company invests in private equity and other investment vehicles as part of the Company’s investment portfolio. The activities of these VIEs are generally limited to holding investments and the Company’s involvement in these entities is passive in nature. The Company’s maximum exposure to the VIEs is the amount of capital invested at any given time, and the Company does not have the power to direct the activities which most significantly impact the VIEs economic performance. The Company is therefore not the primary beneficiary of these VIEs.

Noncontrolling interest

Noncontrolling interest	9 Months Ended
	Sep. 30, 2017
Noncontrolling Interest [Abstract]
Noncontrolling interest	Noncontrolling interests Investors in certain of the AlphaCat and BetaCat ILS funds have rights that enable them, subject to certain limitations, to redeem their shares. The third party equity is therefore recorded in the Company’s Consolidated Balance Sheets as redeemable noncontrolling interests. When and if a redemption notice is received, the fair value of the redemption is reclassified to a liability. The AlphaCat sidecars and one of the AlphaCat ILS funds have no shareholder redemption rights. Therefore, the third party equity is recorded in the Company’s Consolidated Balance Sheets as noncontrolling interests. The following tables present a reconciliation of the beginning and ending balances of redeemable noncontrolling interests and noncontrolling interests for the three and nine months ended September 30, 2017 and 2016 : Redeemable noncontrolling interests Noncontrolling interests Total Three Months Ended September 30, Three Months Ended September 30, Three Months Ended September 30, 2017 2016 2017 2016 2017 2016 Balance, beginning of period $ 1,251,660 $ 1,532,283 $ 415,658 $ 212,154 $ 1,667,318 $ 1,744,437 Issuance of shares 26,999 700 — — 26,999 700 (Loss) income attributable to noncontrolling interests (140,781 ) 26,597 (235,585 ) 10,842 (376,366 ) 37,439 Redemption of shares / distributions (3,998 ) — (101,126 ) — (105,124 ) — Balance, end of period $ 1,133,880 $ 1,559,580 $ 78,947 $ 222,996 $ 1,212,827 $ 1,782,576 Redeemable noncontrolling interests Noncontrolling interests Total Nine Months Ended September 30, Nine Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 2017 2016 Balance, beginning of period $ 1,528,001 $ 1,111,714 $ 165,977 $ 154,662 $ 1,693,978 $ 1,266,376 Issuance of shares 237,199 381,950 258,300 171,674 495,499 553,624 Adjustment to noncontrolling interests as a result of deconsolidation (459,021 ) — — — (459,021 ) — (Loss) income attributable to noncontrolling interests (86,296 ) 72,400 (203,848 ) 23,763 (290,144 ) 96,163 Redemption of shares / distributions (86,003 ) (6,484 ) (141,482 ) (127,103 ) (227,485 ) (133,587 ) Balance, end of period $ 1,133,880 $ 1,559,580 $ 78,947 $ 222,996 $ 1,212,827 $ 1,782,576 As at September 30, 2017 , redemptions of $nil and distributions of $nil (December 31, 2016 : $71,530 and $16,144 ) were payable to redeemable noncontrolling interests and noncontrolling interests, respectively. These amounts are classified within accounts payable and accrued expenses on the Company’s Consolidated Balance Sheets.

Derivative instruments

Derivative instruments	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative instruments	Derivative instruments The Company enters into derivative instruments for risk management purposes, specifically to hedge unmatched foreign currency exposures, interest rate exposures and to shorten the duration of the Company’s fixed maturities portfolio. (a) Derivatives not designated as hedging instruments The following table summarizes information on the classification and amount of the fair value of derivatives not designated as hedging instruments for accounting purposes within the Company’s Consolidated Balance Sheets as at September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 Derivatives not designated as hedging instruments Notional Exposure Asset Derivative at Fair Value (a) Liability Derivative at Fair Value (a) Notional Exposure Asset Derivative at Fair Value (a) Liability Derivative at Fair Value (a) Foreign currency forward contracts $ 267,206 $ 1,522 $ 1,379 $ 181,375 $ 2,351 $ 3,421 Interest rate swap contracts $ 200,000 $ 440 $ 1,607 $ — $ — $ — (a) Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses, respectively, within the Company’s consolidated balance sheets. The following table summarizes information on the classification and net impact on earnings, recognized in the Company’s Consolidated Statements of Income and Comprehensive Income relating to the foreign currency forward and interest rate swap contracts that were not designated as hedging instruments for accounting purposes during the three and nine months ended September 30, 2017 and 2016 : Derivatives not designated as hedging instruments Classification of (losses) gains recognized in earnings Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Foreign currency forward contracts Foreign exchange (losses) gains $ (1,927 ) $ 1,326 $ (7,999 ) $ 209 Foreign currency forward contracts Other loss $ — $ (155 ) $ (979 ) $ (35 ) Interest rate swap contracts Change in unrealized (losses) gains on investments $ (848 ) $ 566 $ (1,167 ) $ 566 (b) Derivatives designated as hedging instruments The following table summarizes information on the classification and amount of the fair value of derivatives designated as hedging instruments for accounting purposes on the Consolidated Balance Sheets as at September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 Derivatives designated as hedging instruments Notional Exposure Asset Derivative at Fair Value (a) Liability Derivative at Fair Value (a) Notional Exposure Asset Derivative at Fair Value (a) Liability Derivative at Fair Value (a) Interest rate swap contracts $ 552,263 $ 20 $ 1,347 $ 552,263 $ 20 $ 1,479 (a) Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses, respectively, within the Company’s consolidated balance sheets. Derivative instruments designated as a cash flow hedge The Company designates its interest rate derivative instruments as cash flow hedges for accounting purposes and formally and contemporaneously documents all relationships between the hedging instruments and hedged items and links the derivative instruments to specific assets and liabilities. The Company assesses the effectiveness of the hedges, both at inception and on an on-going basis and determines whether the hedges are highly effective in offsetting changes in fair value of the linked hedged items. The Company currently applies the long haul method when assessing the hedge’s effectiveness. The following table provides the total impact on other comprehensive income (loss) and earnings relating to the derivative instruments formally designated as cash flow hedges along with the impact of the related hedged items for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, Interest rate swap contracts 2017 2016 2017 2016 Amount of effective portion recognized in other comprehensive income $ 1,918 $ 3,155 $ 6,294 $ 9,505 Amount of effective portion subsequently reclassified to earnings $ (1,931 ) $ (2,717 ) $ (6,261 ) $ (8,373 ) Amount of ineffective portion excluded from effectiveness testing $ 13 $ (438 ) $ (33 ) $ (1,132 ) The above balances relate to interest payments and have therefore been classified as finance expenses in the Consolidated Statements of Income and Comprehensive Income. (c) Classification within the fair value hierarchy As described in Note 5 , “ Fair value measurements ,” under U.S. GAAP, a company must determine the appropriate level in the fair value hierarchy for each fair value measurement. The assumptions used within the valuation of the Company’s derivative instruments are observable in the marketplace, can be derived from observable data or are supported by observable levels at which other similar transactions are executed in the marketplace. Accordingly, these derivatives were classified within Level 2 of the fair value hierarchy. (d) Balance sheet offsetting There was no balance sheet offsetting activity as at September 30, 2017 or December 31, 2016 . The Company currently provides cash collateral as security for interest rate swap contracts. The Company does not provide cash collateral or financial instruments as security for foreign currency forward contracts. Our derivative instruments are generally traded under International Swaps and Derivatives Association master netting agreements, which establish terms that apply to all transactions. On a periodic basis, the amounts receivable from or payable to the counterparties are settled in cash. The Company has not elected to settle multiple transactions with an individual counterparty on a net basis.

Reserve for losses and loss exp

Reserve for losses and loss expenses	9 Months Ended
	Sep. 30, 2017
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]
Reserve for losses and loss expenses	Reserve for losses and loss expenses Reserves for losses and loss expenses are based in part upon the estimation of case reserves from broker, insured and ceding company reported data. The Company also uses statistical and actuarial methods to estimate ultimate expected losses and loss expenses, from which incurred but not reported losses (“IBNR”) can be calculated. The period of time from the occurrence of a loss to the reporting of a loss to the Company and to the settlement of the Company’s liability may be several months or years. During this period, additional facts and trends may be revealed. As these factors become apparent, reserves will be adjusted, sometimes requiring an increase or decrease in the overall reserves of the Company, and at other times requiring a reallocation of incurred but not reported reserves to specific case reserves. These estimates are reviewed and adjusted regularly, and such adjustments, if any, are reflected in earnings in the period in which they become known. While management believes that it has made a reasonable estimate of ultimate losses, there can be no assurances that ultimate losses and loss expenses will not exceed this estimate. The following table summarizes the total reserve for losses and loss expenses as at September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 Case reserves $ 1,271,580 $ 1,237,772 IBNR 3,664,057 1,757,423 Total reserve for losses and loss expenses $ 4,935,637 $ 2,995,195 The following table represents an analysis of paid and unpaid losses and loss expenses incurred and a reconciliation of the beginning and ending unpaid losses and loss expenses for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Reserve for losses and loss expenses, beginning of period $ 3,305,191 $ 3,122,717 $ 2,995,195 $ 2,996,567 Loss reserves recoverable (600,207 ) (442,987 ) (430,421 ) (350,586 ) Net reserves for losses and loss expenses, beginning of period 2,704,984 2,679,730 2,564,774 2,645,981 Net reserves acquired (a) — — 23,753 — Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in: Current year 1,329,666 311,279 1,999,921 959,376 Prior years (75,064 ) (52,885 ) (179,585 ) (169,405 ) Total net incurred losses and loss expenses 1,254,602 258,394 1,820,336 789,971 Less net losses and loss expenses paid in respect of losses occurring in: Current year (191,612 ) (178,707 ) (242,068 ) (240,362 ) Prior years (181,094 ) (166,539 ) (612,448 ) (596,618 ) Total net paid losses (372,706 ) (345,246 ) (854,516 ) (836,980 ) Foreign exchange losses (gains) 13,741 (1,500 ) 46,274 (7,594 ) Net reserve for losses and loss expenses, end of period 3,600,621 2,591,378 3,600,621 2,591,378 Loss reserves recoverable 1,335,016 444,609 1,335,016 444,609 Reserve for losses and loss expenses, end of period $ 4,935,637 $ 3,035,987 $ 4,935,637 $ 3,035,987 (a) Equals net reserves acquired of $42,575 less net reserves commuted at closing of $18,822 . Incurred losses and loss expenses comprise: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Gross losses and loss expenses $ 2,104,914 $ 284,413 $ 2,866,722 $ 952,129 Reinsurance recoverable (850,312 ) (26,019 ) (1,046,386 ) (162,158 ) Net incurred losses and loss expenses $ 1,254,602 $ 258,394 $ 1,820,336 $ 789,971 The net favorable development on prior years by segment and line of business for the three and nine months ended September 30, 2017 and 2016 was as follows: Three Months Ended September 30, 2017 Property Marine Specialty Liability Total Validus Re $ (26,372 ) $ (7,105 ) $ (14,660 ) $ — $ (48,137 ) Talbot (8,752 ) (2,737 ) (12,125 ) — (23,614 ) Western World 464 — — (526 ) (62 ) AlphaCat (1,471 ) — (1,780 ) — (3,251 ) Net favorable development $ (36,131 ) $ (9,842 ) $ (28,565 ) $ (526 ) $ (75,064 ) The net favorable loss reserve development on prior accident years of $75.1 million during the three months ended September 30, 2017 included favorable development on loss events and attritional losses of $16.1 million and $58.9 million , respectively. Three Months Ended September 30, 2016 Property Marine Specialty Liability Total Validus Re $ (19,736 ) $ (8,504 ) $ (4,793 ) $ — $ (33,033 ) Talbot (2,429 ) (4,547 ) (11,715 ) — (18,691 ) Western World (553 ) — — (327 ) (880 ) AlphaCat (265 ) — (16 ) — (281 ) Net favorable development $ (22,983 ) $ (13,051 ) $ (16,524 ) $ (327 ) $ (52,885 ) The net favorable loss reserve development on prior accident years of $52.9 million during the three months ended September 30, 2016 included favorable development on loss events and attritional losses of $20.3 million and $32.6 million , respectively. Nine Months Ended September 30, 2017 Property Marine Specialty Liability Total Validus Re $ (30,614 ) $ (38,847 ) $ (30,555 ) $ — $ (100,016 ) Talbot (19,980 ) (35,789 ) (12,535 ) — (68,304 ) Western World (2,838 ) — — 2,094 (744 ) AlphaCat (8,963 ) — (1,558 ) — (10,521 ) Net (favorable) adverse development $ (62,395 ) $ (74,636 ) $ (44,648 ) $ 2,094 $ (179,585 ) The net favorable loss reserve development on prior accident years of $179.6 million during the nine months ended September 30, 2017 included favorable development on loss events and attritional losses of $31.5 million and $148.0 million , respectively. Nine Months Ended September 30, 2016 Property Marine Specialty Liability Total Validus Re $ (52,036 ) $ (14,967 ) $ (22,591 ) $ — $ (89,594 ) Talbot (30,969 ) (10,511 ) (28,259 ) — (69,739 ) Western World (2,576 ) — — (5,888 ) (8,464 ) AlphaCat (742 ) — (866 ) — (1,608 ) Net favorable development $ (86,323 ) $ (25,478 ) $ (51,716 ) $ (5,888 ) $ (169,405 ) The net favorable development on prior accident years of $169.4 million during the nine months ended September 30, 2016 included favorable development on loss events and attritional losses of $9.0 million and $160.4 million , respectively.

Reinsurance

Reinsurance	9 Months Ended
	Sep. 30, 2017
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance The Company’s reinsurance balances recoverable at September 30, 2017 and December 31, 2016 were as follows: September 30, 2017 December 31, 2016 Loss reserves recoverable on unpaid: Case reserves $ 207,368 $ 165,328 IBNR 1,127,648 265,093 Total loss reserves recoverable 1,335,016 430,421 Paid losses recoverable 77,730 35,247 Total reinsurance balances recoverable $ 1,412,746 $ 465,668 The Company enters into reinsurance and retrocession agreements in order to mitigate its accumulation of loss, reduce its liability on individual risks, enable it to underwrite policies with higher limits and increase its aggregate capacity. The cession of insurance and reinsurance does not legally discharge the Company from its primary liability for the full amount of the policies, and the Company is required to pay the loss and bear collection risk if the reinsurer fails to meet its obligations under the reinsurance or retrocession agreement. Amounts recoverable from reinsurers are estimated in a manner consistent with the underlying liabilities. Credit risk The Company evaluates the financial condition of its reinsurers and monitors concentration of credit risk arising from its exposure to individual reinsurers. The reinsurance program is generally placed with reinsurers whose rating, at the time of placement, was A- or better as rated by Standard & Poor’s or the equivalent with other rating agencies. Exposure to a single reinsurer is also controlled with restrictions dependent on rating. As at September 30, 2017 , $1,400,430 or 99.1% ( December 31, 2016 : $461,369 or 99.1% ) of the Company’s reinsurance balances recoverable were either fully collateralized or recoverable from reinsurers rated A- or better. Reinsurance balances recoverable by reinsurer as at September 30, 2017 and December 31, 2016 were as follows: September 30, 2017 December 31, 2016 Reinsurance Recoverable % of Total Reinsurance Recoverable % of Total Top 10 reinsurers $ 1,208,003 85.5 % $ 395,308 84.9 % Other reinsurers’ balances > $1 million 198,774 14.1 % 66,944 14.4 % Other reinsurers’ balances < $1 million 5,969 0.4 % 3,416 0.7 % Total $ 1,412,746 100.0 % $ 465,668 100.0 % The following tables show the reinsurance balances recoverable due from, and the ratings associated with, the Company’s top ten reinsurers as at September 30, 2017 and December 31, 2016 : September 30, 2017 Top 10 Reinsurers Rating Reinsurance Recoverable % of Total Fully collateralized reinsurers NR $ 564,714 40.0 % Munich Re AA- 164,131 11.6 % Everest Re A+ 95,759 6.8 % Lloyd's Syndicates A+ 94,845 6.7 % Swiss Re AA- 81,921 5.8 % Hannover Re AA- 62,715 4.4 % Federal Crop Insurance Corporation (a) 49,503 3.5 % Qatar Insurance Company A 38,061 2.7 % Transatlantic Re A+ 29,795 2.1 % XL Catlin A+ 26,559 1.9 % Total $ 1,208,003 85.5 % (a) The Company participates in a crop reinsurance program sponsored by the U.S. federal government. The Company remains obligated for amounts ceded in the event that its reinsurers or retrocessionaires do not meet their obligations, except for amounts ceded to the U.S. federal government in the agriculture line of business. December 31, 2016 Top 10 Reinsurers Rating Reinsurance Recoverable % of Total Lloyd's Syndicates A+ $ 84,419 18.2 % Swiss Re AA- 84,044 18.1 % Fully collateralized reinsurers NR 83,088 17.8 % Hannover Re AA- 50,603 10.9 % Everest Re A+ 36,912 7.9 % Munich Re AA- 18,214 3.9 % Transatlantic Re A+ 10,593 2.3 % Hamilton Re A- 10,343 2.2 % Toa Re A+ 9,510 2.0 % National Indemnity Company AA+ 7,582 1.6 % Total $ 395,308 84.9 % At September 30, 2017 and December 31, 2016 , the provision for uncollectible reinsurance relating to reinsurance balances recoverable was $8,326 and $5,153 , respectively. To estimate this provision for uncollectible reinsurance, reinsurance balances recoverable are first allocated to applicable reinsurers. This determination is based on a process rather than an estimate, although an element of judgment is applied, especially in relation to ceded IBNR. The Company then uses default factors to determine the portion of a reinsurer’s balance deemed to be uncollectible. Default factors require considerable judgment and are determined in part using the current rating, or rating equivalent, of each reinsurer as well as other key considerations and assumptions.

Share capital

Share capital	9 Months Ended
	Sep. 30, 2017
Stockholders' Equity Note [Abstract]
Share capital	Share capital The Company is authorized to issue up to an aggregate of 571,428,571 common and preferred shares with a par value of $0.175 per share. (a) Preferred shares On June 12, 2017, the Company issued 10,000 shares of its 5.800% Non-Cumulative Preferred Shares, Series B (the “Series B Preferred Shares”) (equivalent to 10,000,000 Depositary Shares, each of which represents a 1/1,000th interest in a Series B Preferred Share), $0.175 par value and $25,000 liquidation preference per share (equivalent to $25 per Depositary Share). The Series B Preferred Shares were registered and sold under the Securities Act of 1933, as amended, and were issued at a price to the public of $25,000 per share (equivalent to $25 per Depositary Share). After underwriting discounts and expenses, the Company received net proceeds of $241,686 which was used for general corporate purposes. The Depositary Shares, representing the Series B Preferred Shares, are traded on the New York Stock Exchange (“NYSE”) under the symbol “VRPRB.” The Series B Preferred Shares have no stated maturity date and are redeemable, in whole or in part, at the Company’s option on and after June 21, 2022, at a redemption price of $25,000 per Series B Preferred Share (equivalent to $25 per Depository Share), plus declared and unpaid dividends. The Company may also redeem all, but not less than all, of the Series B Preferred Shares before the redemption date at a redemption price of $26,000 per share (equivalent to $26 per Depository Share), plus declared and unpaid dividends, if the Company is required to submit a proposal to the holders of the Series B Preferred Shares concerning an amalgamation, consolidation, merger or other similar corporate transaction or change in Bermuda law. The Series B Preferred Shares may also be redeemed before the redemption date at a redemption price of $25,000 per Series B Preferred Share (equivalent to $25 per Depository Share), plus declared and unpaid dividends, in whole, if there is a certain change in tax law, or in whole or in part, in the case of a capital disqualification event. However, no redemption may occur prior to June 21, 2027 unless the Company has sufficient funds in order to meet the Bermuda Monetary Authority’s (“the BMA”) Enhanced Capital Requirements (“ECR”) and the BMA approves of the redemption, or the Company replaces the capital represented by the Series B Preferred Shares with capital having equal or better capital treatment as the Series B Preferred Shares under the ECR. Dividends on the Series B Preferred Shares, when, as and if declared by the Company’s Board of Directors or a duly authorized committee thereof, will accrue and be payable on the liquidation preference amount from the original issue date, on a non-cumulative basis, quarterly in arrears on each dividend payment date at an annual rate of 5.800% . The Company will be restricted from paying dividends on and repurchasing its common shares, unless certain dividend payments are made on the Series B Preferred Shares. Upon any voluntary or involuntary liquidation, dissolution or winding up of the Company, holders of the Series B Preferred Shares and any parity shares are entitled to receive out of our assets available for distribution to shareholders, before any distribution is made to holders of common shares or other junior shares, a liquidating distribution in the amount of $25,000 per Series B Preferred Share (equivalent to $25 per Depositary Share) plus declared and unpaid dividends. Distributions will be made pro rata in accordance with the respective aggregate liquidation preferences of the Series B Preferred Shares and any parity shares and only to the extent of our assets, if any, that are available after satisfaction of all liabilities to creditors. Holders of the Series B Preferred Shares have no voting rights, except with respect to certain fundamental changes in the terms of the Series B Preferred Shares and in the case of certain dividend non-payments or as otherwise required by Bermuda law or the Company’s bye-laws. On June 13, 2016, the Company issued 6,000 shares of its 5.875% Non-Cumulative Preferred Shares, Series A (the “Series A Preferred Shares”) (equivalent to 6,000,000 Depositary Shares, each of which represents a 1/1,000th interest in a Series A Preferred Share), $0.175 par value and $25,000 liquidation preference per share (equivalent to $25 per Depositary Share). Holders of the Series A Preferred Shares have no voting rights, except with respect to certain fundamental changes in the terms of the Series A Preferred Shares and in the case of certain dividend non-payments or as otherwise required by Bermuda law or the Company’s bye-laws. The following table is a summary of the preferred share activity during the nine months ended September 30, 2017 and 2016 : Nine Months Ended September 30, 2017 2016 Preferred shares issued and outstanding, beginning of period 6,000 — Preferred shares issued 10,000 6,000 Preferred shares issued and outstanding, end of period 16,000 6,000 The Company had 6,000 Series A Preferred Shares and 10,000 Series B Preferred Shares issued and outstanding as at September 30, 2017 and 6,000 Series A Preferred Shares issued and outstanding as at December 31, 2016. (b) Common Shares The holders of common shares are entitled to receive dividends and are allocated one vote per share , provided that, if the controlled shares of any shareholder or group of related shareholders constitute more than 9.09 percent of the outstanding common shares of the Company, their voting power will be reduced to 9.09 percent. The Company may from time to time repurchase its securities, including common shares, Junior Subordinated Deferrable Debentures and Senior Notes. On February 3, 2015, the Board of Directors of the Company approved an increase in the Company’s common share repurchase authorization to $750,000 . This amount is in addition to the $2,274,401 of common shares repurchased by the Company through February 3, 2015 under its previously authorized share repurchase programs. The Company has repurchased 80,860,661 common shares for an aggregate purchase price of $2,722,749 from the inception of its share repurchase program to September 30, 2017 . The Company had $301,652 remaining under its authorized share repurchase program as of September 30, 2017 . The Company expects the purchases under its share repurchase program to be made from time to time in the open market or in privately negotiated transactions. The timing, form and amount of the share repurchases under the program will depend on a variety of factors, including market conditions, the Company’s capital position relative to internal and rating agency targets, legal requirements and other factors. The repurchase program may be modified, extended or terminated by the Board of Directors at any time. The following table is a summary of the common share activity during the nine months ended September 30, 2017 and 2016 : Nine Months Ended September 30, 2017 2016 Common shares issued, beginning of period 161,279,976 160,570,772 Restricted share awards vested, net of shares withheld 619,046 608,024 Restricted share units vested, net of shares withheld 15,454 18,486 Options exercised — 27,983 Performance share awards vested, net of shares withheld 42,410 48,088 Common shares issued, end of period 161,956,886 161,273,353 Treasury shares, end of period (82,499,633 ) (81,830,323 ) Common shares outstanding, end of period 79,457,253 79,443,030 (c) Dividends On August 9, 2017 , the Company announced a quarterly cash dividend of $0.38 ( 2016 : $0.35 ) per common share and cash dividends of $0.3671875 ( 2016 : $0.3753472 ) and $0.3423611 per depositary share on its outstanding Series A and Series B Preferred Shares, respectively. The common share dividend was paid on September 29, 2017 to holders of record on September 15, 2017 . The preferred share dividends were paid on September 15, 2017 to shareholders of record on September 1, 2017. On May 10, 2017, the Company announced a quarterly cash dividend of $0.38 (2016: $0.35 ) per common share and a cash dividend of $0.3671875 per depositary share on its outstanding Series A Preferred Shares. The common share dividend was paid on June 30, 2017 to holders of record on June 15, 2017. The preferred share dividend was paid on June 15, 2017 to holders of record on June 1, 2017. On February 9, 2017, the Company announced a quarterly cash dividend of $0.38 (2016: $0.35 ) per common share and a cash dividend of $0.3671875 per depositary share on its outstanding Series A Preferred Shares. The common share dividend was paid on March 31, 2017 to holders of record on March 15, 2017. The preferred share dividend was paid on March 15, 2017 to holders of record on March 1, 2017.

Stock plans

Stock plans	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock plans	Stock plans (a) Long Term Incentive Plan The Company’s Amended and Restated 2005 Long Term Incentive Plan (“LTIP”) provides for grants to employees of options, stock appreciation rights (“SARs”), restricted shares, restricted share units, performance shares, dividend equivalents or other share-based awards. The total number of shares reserved for issuance under the LTIP are 2,753,292 shares of which 701,617 shares remain available for issuance at September 30, 2017 . The LTIP is administered by the Compensation Committee of the Board of Directors. No SARs have been granted to date. Grant prices are established at the fair market value of the Company’s common shares at the date of grant. i. Options Options may be exercised for voting common shares upon vesting. Outstanding options have a life of 10 years and vest either pro rata or at the end of the required service period from the date of grant. Fair value of the option awards at the date of grant is determined using the Black-Scholes option-pricing model. Expected volatility is based on stock price volatility of comparable publicly-traded companies. The Company used the simplified method consistent with U.S. GAAP authoritative guidance on stock compensation expenses to estimate expected lives for options granted during the period as historical exercise data was not available and the options met the requirement as set out in the guidance. The Company has not granted any stock option awards since September 4, 2009. These stock option awards were fully amortized during the year ended December 31, 2012. Activity with respect to options for the nine months ended September 30, 2017 and 2016 was as follows: Nine Months Ended September 30, 2017 2016 Options Weighted Average Grant Date Fair Value Weighted Average Grant Date Exercise Price Options Weighted Average Grant Date Fair Value Weighted Average Grant Date Exercise Price Options outstanding, beginning of period 26,136 $ 6.78 $ 23.48 65,401 $ 7.74 $ 20.17 Options exercised — — — (35,351 ) 8.16 17.82 Options outstanding, end of period 26,136 $ 6.78 $ 23.48 30,050 $ 7.24 $ 22.93 ii. Restricted share awards Restricted shares granted under the LTIP vest either pro rata or at the end of the required service period and contain certain restrictions during the vesting period, relating to, among other things, forfeiture in the event of termination of employment and transferability. The Company recognized share compensation expenses in respect of restricted share awards during the three and nine months ended September 30, 2017 of $7,814 ( 2016 : $9,159 ) and $26,603 ( 2016 : $27,805 ), respectively. The expenses represent the proportionate accrual of the fair value of each grant based on the remaining vesting period. Activity with respect to unvested restricted share awards for the nine months ended September 30, 2017 and 2016 was as follows: Nine Months Ended September 30, 2017 2016 Restricted Share Awards Weighted Average Grant Date Fair Value Restricted Share Awards Weighted Average Grant Date Fair Value Restricted share awards outstanding, beginning of period 2,469,982 $ 40.89 2,739,446 $ 38.25 Restricted share awards granted 508,186 53.25 559,516 48.78 Restricted share awards vested (828,800 ) 41.25 (789,547 ) 37.36 Restricted share awards forfeited (53,775 ) 43.38 (33,070 ) 40.25 Restricted share awards outstanding, end of period 2,095,593 $ 43.69 2,476,345 $ 40.88 At September 30, 2017 , there were $57,065 ( December 31, 2016 : $58,804 ) of total unrecognized share compensation expenses in respect of restricted share awards that are expected to be recognized over a weighted-average period of 2.4 years ( December 31, 2016 : 2.3 years ). iii. Restricted share units Restricted share units under the LTIP vest either ratably or at the end of the required service period and contain certain restrictions during the vesting period, relating to, among other things, forfeiture in the event of termination of employment and transferability. The Company recognized share compensation expenses in respect of restricted share units during the three and nine months ended September 30, 2017 of $340 ( 2016 : $290 ) and $982 ( 2016 : $978 ), respectively. The expenses represent the proportionate accrual of the fair value of each grant based on the remaining vesting period. Activity with respect to unvested restricted share units for the nine months ended September 30, 2017 and 2016 was as follows: Nine Months Ended September 30, 2017 2016 Restricted Share Units Weighted Average Grant Date Fair Value Restricted Share Units Weighted Average Grant Date Fair Value Restricted share units outstanding, beginning of period 112,808 $ 40.95 114,337 $ 38.47 Restricted share units granted 12,236 53.40 21,609 48.83 Restricted share units vested (18,748 ) 41.91 (23,982 ) 38.18 Restricted share units issued in lieu of cash dividends 2,260 41.42 2,436 39.10 Restricted share units forfeited — — (8,338 ) 44.34 Restricted share units outstanding, end of period 108,556 $ 42.20 106,062 $ 40.20 At September 30, 2017 , there were $2,233 ( December 31, 2016 : $2,542 ) of total unrecognized share compensation expenses in respect of restricted share units that are expected to be recognized over a weighted-average period of 2.5 years ( December 31, 2016 : 2.6 years ). iv. Performance share awards The performance share awards contain a performance based component. The performance component relates to the compounded growth in the Dividend Adjusted Diluted Book Value per Share (“DBVPS”) over a three -year period relative to the Company’s peer group. For performance share awards granted during the period, the grant date DBVPS is based on the DBVPS at the end of the most recent financial reporting year. The Dividend Adjusted Performance Period End DBVPS will be the DBVPS three years after the grant date DBVPS. The fair value estimate earns over the requisite attribution period and the estimate will be reassessed at the end of each performance period which will reflect any adjustments in the Consolidated Statements of Income and Comprehensive Income in the period in which they are determined. The Company recognized share compensation expenses in respect of performance share awards during the three and nine months ended September 30, 2017 of $1,289 ( 2016 : $1,052 ) and $2,495 ( 2016 : $3,682 ), respectively. Activity with respect to unvested performance share awards for the nine months ended September 30, 2017 and 2016 was as follows: Nine Months Ended September 30, 2017 2016 Performance Share Awards Weighted Average Grant Date Fair Value Performance Share Awards Weighted Average Grant Date Fair Value Performance share awards outstanding, beginning of period 285,820 $ 44.53 172,594 $ 40.70 Performance share awards granted 107,209 53.40 125,290 48.75 Performance share awards vested (52,639 ) 37.33 (57,581 ) 36.11 Performance share awards conversion adjustment (26,322 ) 36.82 45,517 36.82 Performance share awards outstanding, end of period 314,068 $ 49.37 285,820 $ 44.53 At September 30, 2017 , there were $9,031 ( December 31, 2016 : $6,902 ) of total unrecognized share compensation expenses in respect of performance share awards that are expected to be recognized over a weighted-average period of 2.1 years ( December 31, 2016 : 2.1 years ). (b) Total share compensation expenses The breakdown of share compensation expenses by award type for the periods indicated was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Restricted share awards $ 7,814 $ 9,159 $ 26,603 $ 27,805 Restricted share units 340 290 982 978 Performance share awards 1,289 1,052 2,495 3,682 Total $ 9,443 $ 10,501 $ 30,080 $ 32,465

Debt and financing arrangements

Debt and financing arrangements	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Debt and financing arrangements	Debt and financing arrangements The Company’s financing structure is comprised of debentures and senior notes payable along with credit and other facilities. (a) Senior notes and junior subordinated deferrable debentures The Company’s outstanding debentures and senior notes payable as at September 30, 2017 and December 31, 2016 were as follows: September 30, 2017 December 31, 2016 Deferrable debentures 2006 Junior Subordinated $ 150,000 $ 150,000 2007 Junior Subordinated 139,800 139,800 Flagstone 2006 Junior Subordinated 135,360 133,676 Flagstone 2007 Junior Subordinated 113,750 113,750 Total debentures payable 538,910 537,226 2010 Senior notes payable 250,000 250,000 Less: Unamortized debt issuance costs (4,487 ) (4,638 ) Total senior notes payable 245,513 245,362 Total debentures and senior notes payable $ 784,423 $ 782,588 The following table summarizes the key terms of the Company’s senior notes and junior subordinated deferrable debentures: Description Issuance date Issued Maturity date Interest Rate as at Interest payments due Issuance Date September 30, 2017 2006 Junior Subordinated Deferrable Debentures June 15, 2006 $ 150,000 June 15, 2036 9.069 % (a) 5.831 % (e) Quarterly Flagstone 2006 Junior Subordinated Deferrable Debentures August 23, 2006 $ 135,360 September 15, 2036 3.540 % (b) 6.463 % (e) Quarterly 2007 Junior Subordinated Deferrable Debentures June 21, 2007 $ 200,000 June 15, 2037 8.480 % (c) 5.180 % (e) Quarterly Flagstone 2007 Junior Subordinated Deferrable Debentures June 8, 2007 $ 100,000 July 30, 2037 3.000 % (b) 5.900 % (e) Quarterly Flagstone 2007 Junior Subordinated Deferrable Debentures September 20, 2007 $ 25,000 September 15, 2037 3.100 % (b) 5.983 % (e) Quarterly 2010 Senior Notes due 2040 January 26, 2010 $ 250,000 January 26, 2040 8.875 % (d) 8.875 % (d) Semi-annually in arrears (a) Fixed interest rate for 5 years , floating interest rate of three-month LIBOR plus 3.550% thereafter, reset quarterly. (b) Floating interest rate of three-month LIBOR plus amount stated, reset quarterly. (c) Fixed interest rate for 5 years , floating interest rate of three-month LIBOR plus 2.950% thereafter, reset quarterly. (d) Fixed interest rate. (e) Fixed interest rate as a result of interest rate swap contracts entered into by the Company. Future payments of principal of $250,000 and $538,910 on the 2010 Senior Notes and the debentures, respectively, are expected to be made after 2022. (b) Credit and other facilities The Company’s outstanding credit facilities as at September 30, 2017 and December 31, 2016 were as follows: September 30, 2017 Commitment Outstanding (a) Drawn (b) Cash and investments pledged as collateral Credit facilities $85,000 syndicated unsecured letter of credit facility $ 85,000 $ — $ — $ — $300,000 syndicated secured letter of credit facility 300,000 89,449 — 108,265 $24,000 secured bi-lateral letter of credit facility 24,000 5,767 — 22,342 $25,000 IPC bi-lateral facility 25,000 7,755 — — $236,000 Flagstone bi-lateral facility 236,000 90,390 — 134,482 $65,000 unsecured revolving credit facility 65,000 65,000 65,000 — $100,000 unsecured revolving credit facility 100,000 100,000 100,000 — Total credit facilities $ 835,000 $ 358,361 $ 165,000 $ 265,089 (a) Indicates utilization of commitment amount, not drawn borrowings. (b) Represents drawn borrowings included in accounts payable and accrued expenses. December 31, 2016 Commitment Outstanding (a) Drawn (b) Cash and investments pledged as collateral Credit facilities $85,000 syndicated unsecured letter of credit facility $ 85,000 $ — $ — $ — $300,000 syndicated secured letter of credit facility 300,000 121,428 — 157,597 $24,000 secured bi-lateral letter of credit facility 24,000 4,553 — 48,097 $20,000 AlphaCat Re secured letter of credit facility (c) 20,000 20,000 — 20,032 $25,000 IPC bi-lateral facility 25,000 8,807 — — $236,000 Flagstone bi-lateral facility 236,000 156,375 — 216,458 Total credit facilities $ 690,000 $ 311,163 $ — $ 442,184 (a) Indicates utilization of commitment amount, not drawn borrowings. (b) Represents drawn borrowings. (c) The Company terminated its AlphaCat Re secured letter of credit facility on January 6, 2017. On August 7, 2017, the Company and Validus Reinsurance, Ltd. entered into a $65,000 unsecured revolving credit facility with Barclays Bank PLC, as the lender (the “Barclays Unsecured Revolving Facility”) expiring August 6, 2018. Loans under the Barclays Unsecured Revolving Facility will be available for the general corporate and working capital purposes of the Company. Borrowings under the Barclays Unsecured Revolving Facility bear interest at the base rate (the higher of (i) the prime rate quoted in the Wall Street Journal, (ii) the federal reserve bank effective rate plus 0.50% , and (iii) the adjusted LIBOR rate plus 1.0% ) or the adjusted LIBOR rate applicable to such loans, plus an applicable rate. Also on August 7, 2017, the Company and Validus Reinsurance, Ltd. entered into a $100,000 unsecured revolving credit facility with HSBC Bank USA, National Association, as the lender (the “HSBC Unsecured Revolving Facility” and together with the Barclays Unsecured Revolving Facility, the “Credit Facilities”) expiring December 31, 2019. Loans under the HSBC Unsecured Revolving Facility will be available for the general corporate and working capital purposes of the Company. Borrowings under the HSBC Unsecured Revolving Facility bear interest at the base rate (the higher of (i) the prime rate announced by HSBC Bank USA, National Association, (ii) the higher of the federal reserve bank effective rate the overnight bank funding rate plus 0.50% , or (iii) the adjusted LIBOR rate plus 1.0% ). The Credit Facilities contain covenants that include, among other things (i) the requirement that the Company initially maintain a minimum level of consolidated net worth of at least $2,789,131 and, commencing with the end of the fiscal quarter ending September 30, 2017, to be increased quarterly by an amount equal to 25% of the Company’s consolidated net income (if positive) for such quarter plus 50% of the aggregate increases in the consolidated shareholders’ equity of the Company during such fiscal quarter by reason of the issuance and sale of common equity interests of the Company, including upon any conversion of debt securities of the Company into such equity interests, (ii) the requirement that the Company maintain at all times a consolidated total debt to consolidated total capital ratio not greater than 0.35:1.00 , and (iii) the requirement that Validus Reinsurance, Ltd. and any certain other material insurance subsidiaries maintain a financial strength rating by A.M. Best of not less than “B++” (Fair). In addition, the Credit Facilities contain customary negative covenants applicable to the Company and its subsidiaries, including limitations on the ability to pay dividends and other payments in respect of equity interests at any time that the Company is otherwise in default with respect to certain provisions under the respective Credit Facilities, limitations on the ability to incur liens, sell assets, merge or consolidate with others, enter into transactions with affiliates, and limitations on the ability of its subsidiaries to incur indebtedness. The Credit Facilities also contain customary affirmative covenants, representations and warranties and events of default for credit facilities of its type. As of September 30, 2017 and December 31, 2016 , the Company was in compliance with all covenants and restrictions under its credit and other facilities. (c) Finance expenses Finance expenses consist of interest on the junior subordinated deferrable debentures and senior notes, the amortization of debt offering costs, credit facility fees, bank charges, AlphaCat financing fees and other charges as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 2006 Junior Subordinated Deferrable Debentures $ 2,235 $ 2,135 $ 6,633 $ 6,557 2007 Junior Subordinated Deferrable Debentures 1,851 1,851 5,492 5,512 Flagstone 2006 Junior Subordinated Deferrable Debentures 2,272 2,271 6,741 6,760 Flagstone 2007 Junior Subordinated Deferrable Debentures 1,775 1,784 5,249 5,317 2010 Senior Notes due 2040 5,597 5,597 16,792 16,791 Credit facilities 575 463 1,196 1,359 Bank and other charges 183 276 465 489 AlphaCat fees (a) 35 144 107 1,105 Total finance expenses $ 14,523 $ 14,521 $ 42,675 $ 43,890 (a) Includes finance expenses incurred by AlphaCat Managers Ltd. in relation to fund raising for the AlphaCat sidecars, the AlphaCat ILS funds and AlphaCat direct.

Accumulated other comprehensive

Accumulated other comprehensive loss	9 Months Ended
	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive loss	Accumulated other comprehensive loss The changes in accumulated other comprehensive loss, by component for the three and nine months ended September 30, 2017 and 2016 was as follows: Three Months Ended September 30, 2017 Foreign currency translation adjustment Minimum pension liability Cash flow hedge Total Balance, net of tax, beginning of period $ (20,188 ) $ 1,102 $ (838 ) $ (19,924 ) Other comprehensive income, net of tax 1,481 — 13 1,494 Balance, net of tax, end of period $ (18,707 ) $ 1,102 $ (825 ) $ (18,430 ) Three Months Ended September 30, 2016 Foreign currency translation adjustment Minimum pension liability Cash flow hedge Total Balance, net of tax, beginning of period $ (17,149 ) $ 730 $ (1,763 ) $ (18,182 ) Other comprehensive loss, net of tax (1,370 ) (1,101 ) (439 ) (2,910 ) Balance, net of tax, end of period $ (18,519 ) $ (371 ) $ (2,202 ) $ (21,092 ) Nine Months Ended September 30, 2017 Foreign currency translation adjustment Minimum pension liability Cash flow hedge Total Balance, net of tax, beginning of period $ (22,274 ) $ (150 ) $ (792 ) $ (23,216 ) Other comprehensive income (loss), net of tax 3,567 1,252 (33 ) 4,786 Balance, net of tax, end of period $ (18,707 ) $ 1,102 $ (825 ) $ (18,430 ) Nine Months Ended September 30, 2016 Foreign currency translation adjustment Minimum pension liability Cash flow hedge Total Balance, net of tax, beginning of period $ (11,834 ) $ 334 $ (1,069 ) $ (12,569 ) Other comprehensive loss, net of tax (6,685 ) (705 ) (1,133 ) (8,523 ) Balance, net of tax, end of period $ (18,519 ) $ (371 ) $ (2,202 ) $ (21,092 )

Commitments and contingencies

Commitments and contingencies	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	Commitments and contingencies (a) Funds at Lloyd’s Talbot operates in Lloyd’s through a corporate member, Talbot 2002 Underwriting Capital Ltd (“T02”), which is the sole participant in Syndicate 1183. Lloyd’s sets T02’s required capital annually based on Syndicate 1183’s business plan, rating environment and reserving environment together with input arising from Lloyd’s discussions with, inter alia, regulatory and rating agencies. Such capital, called Funds at Lloyd’s (“FAL”), comprises cash and investments. The Company provided FAL in the amount of $583,600 for the 2017 underwriting year ( 2016 underwriting year: $617,000 ). The amounts which are provided as FAL are not available for distribution to the Company for the payment of dividends. Talbot’s corporate member may also be required to maintain funds under the control of Lloyd’s in excess of its capital requirement and such funds also may not be available for distribution to the Company for the payment of dividends. (b) Lloyd’s Central Fund Whenever a member of Lloyd’s is unable to pay its debts to policyholders, such debts may be payable by the Lloyd’s Central Fund. If Lloyd’s determines that the Central Fund needs to be increased, it has the power to assess premium levies on current Lloyd’s members up to 3% of a member’s underwriting capacity in any one year. The Company does not believe that any assessment is likely in the foreseeable future and has not provided any allowance for such an assessment. However, based on the Company’s 2017 underwriting capacity at Lloyd’s of £600,000 , at the September 30, 2017 exchange rate of £1 equals $1.34 and assuming the maximum 3% assessment, the Company would be assessed approximately $24,120 . (c) Marketing Services Agreement (“MSA”) On May 1, 2017, the Company entered into a MSA with Archer Daniels Midland (“ADM”). Under this agreement, ADM agrees to provide marketing services via its own distribution channels for an annual fee of $2,000 for a period of seven years , with an option for the Company to extend for an additional three years . For the three and nine months ended September 30, 2017 , the Company had incurred fees in relation to the MSA of $500 and $833 , respectively. (d) Unfunded investment commitments As at September 30, 2017 and December 31, 2016 , the Company had total unfunded investment commitments related to the following: Unfunded investment commitments September 30, 2017 December 31, 2016 Fixed maturity investments (a) $ 21,959 $ 28,499 Other investments (b) 101,082 156,134 Investments in investment affiliates (c) 87,372 64,071 AlphaCat ILS Fund — 10,000 Total unfunded investment commitments $ 210,413 $ 258,704 (a) The Company has an outstanding commitment to participate in certain secured loan facilities through participation agreements with an established loan originator. (b) The Company’s total capital commitments related to other investments as at September 30, 2017 was $313,000 ( December 31, 2016 : $308,000 ). (c) Refer to Note 4 (c), “Investments in Investment Affiliates.”

Related party transactions

Related party transactions	9 Months Ended
	Sep. 30, 2017
Related Party Transactions [Abstract]
Related party transactions	Related party transactions The transactions listed below are classified as related party transactions as principals and/or directors of each counterparty are members of the Company’s board of directors. (a) Aquiline Capital Partners LLC (“Aquiline Capital”) Group Ark Insurance Subsequent to July 2016, Aquiline Capital ceased to be shareholders of Group Ark Insurance Holdings Ltd. (“Group Ark”). Christopher E. Watson, a director of the Company and senior principal of Aquiline Capital, continues to serve as a director of Group Ark. Pursuant to reinsurance agreements with a subsidiary of Group Ark, the Company recognized gross premiums written during the three and nine months ended September 30, 2016 of $1,096 and $3,067 , respectively. The Company also recognized reinsurance premiums ceded during the three and nine months ended September 30, 2016 of $41 and $41 , respectively. Earned premium adjustments were recorded during the three and nine months ended September 30, 2016 of $1,276 and $2,275 , respectively. As at December 31, 2016 the Company had recorded premiums receivable and loss reserves recoverable of $292 and $798 , respectively. Wellington Pursuant to reinsurance agreements with a subsidiary of Wellington Insurance Company (“Wellington”), during the three and nine months ended September 30, 2017 the Company recognized gross premiums written of $78 and $4,196 ( 2016 : $nil and $nil ), respectively, and earned premium adjustments of $943 and $3,480 ( 2016 : $nil and $nil ), respectively. As at September 30, 2017 and December 31, 2016 the Company had recorded premiums receivable of $468 and $666 , respectively. Aquiline Capital are shareholders of Wellington and Christopher E. Watson, a director of the Company and senior principal of Aquiline Capital, serves as a director of Wellington. Aquiline II, Aquiline III and Aquiline Tech The Company had, as of September 30, 2017 and December 31, 2016 , investments in Aquiline II, III and Tech with a total value of $92,079 and $100,431 and outstanding unfunded commitments of $87,372 and $64,071 , respectively. For the three and nine months ended September 30, 2017 , the Company incurred $106 and $592 ( 2016 : $520 and $1,535 ), respectively, in partnership fees associated with these investments. Jeffrey W. Greenberg and Christopher E. Watson, directors of the Company, serve as managing principal and senior principal, respectively, of Aquiline Capital. Additional information related to Aquiline II, III and Tech is disclosed in Note 4 (c), “Investments in Investment Affiliates.” (b) Other Certain shareholders of the Company and their affiliates, as well as employers of entities associated with directors or officers have purchased insurance and/or reinsurance from the Company in the ordinary course of business. The Company believes these transactions were settled for arm’s length consideration.

Earnings per share

Earnings per share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings per common share	Earnings per common share The following table sets forth the computation of basic earnings per common share and earnings per diluted common share for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Basic (loss) earnings per common share Net (loss) income (attributable) available to Validus common shareholders $ (250,446 ) $ 89,844 $ (54,790 ) $ 351,617 Weighted average number of common shares outstanding 78,994,335 80,134,394 79,132,856 81,635,496 Basic (loss) earnings per share (attributable) available to Validus common shareholders $ (3.17 ) $ 1.12 $ (0.69 ) $ 4.31 (Loss) earnings per diluted common share Net (loss) income (attributable) available to Validus common shareholders $ (250,446 ) $ 89,844 $ (54,790 ) $ 351,617 Weighted average number of common shares outstanding 78,994,335 80,134,394 79,132,856 81,635,496 Share equivalents: Stock options — 26,705 — 32,126 Unvested restricted shares — 1,083,457 — 1,271,002 Weighted average number of diluted common shares outstanding 78,994,335 81,244,556 79,132,856 82,938,624 (Loss) earnings per diluted share (attributable) available to Validus common shareholders $ (3.17 ) $ 1.11 $ (0.69 ) $ 4.24 Earnings per diluted common share assumes the exercise of all dilutive stock options and restricted stock grants. Due to the net loss incurred during the three and nine months ended September 30, 2017, share equivalents were not included in the computation of diluted loss per share due to their anti-dilutive effect. Share equivalents that would result in the issuance of common shares of 19,808 and 175,690 were outstanding for the three and nine months ended September 30, 2016, respectively, but were not included in the computation of earnings per diluted common share because the effect would be anti-dilutive.

Segment information

Segment information	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment information	Segment information The Company conducts its operations worldwide through four operating segments, which have been determined under ASC Topic 280 “Segment Reporting” to be Validus Re, Talbot, Western World and AlphaCat. For segmental reporting purposes, the results of CRS have been included in the results of the Western World segment as of May 1, 2017, the date of acquisition. The Company’s operating segments are strategic business units that offer different products and services. They are managed and have capital allocated separately because each segment undertakes different strategies. A description of each of the Company’s operating segments and its Corporate and Investments function is as follows: Validus Re Segment The Validus Re segment is focused primarily on treaty reinsurance. The primary lines in which the segment conducts business are property, marine and specialty which includes agriculture, aerospace and aviation, financial lines of business, nuclear, terrorism, life, accident & health, workers’ compensation, crisis management, contingency, technical lines, composite, trade credit and casualty. Talbot Segment The Talbot segment is focused on a wide range of marine and energy, political lines, commercial property, financial lines, contingency, accident & health and aviation classes of business on an insurance or facultative reinsurance basis and principally property, aerospace and marine classes of business on a treaty reinsurance basis. Western World Segment The Western World segment is focused on providing commercial insurance products on a surplus lines and specialty admitted basis. Western World specializes in underwriting classes of business that are not easily placed in the standard insurance market due to their complexity, high hazard, or unusual nature; including general liability, property and professional liability, homeowners, commercial package and agriculture classes of business. AlphaCat Segment The AlphaCat segment leverages the Company’s underwriting and analytical expertise and earns management and performance fees from the Company and other third party investors primarily through the AlphaCat ILS funds and sidecars. Corporate and Investments The Company has a corporate and investments function (“Corporate and Investments”), which includes the activities of the parent company, and which carries out certain functions for the group, including investment management. Corporate and Investments includes investment income on a managed basis and other non-segment expenses, predominantly general and administrative, stock compensation, finance and transaction expenses. Transaction expenses are primarily comprised of legal, financial advisory and audit related services incurred in connection with the acquisition of CRS. Corporate and Investments also includes the activities of certain key executives such as the Chief Executive Officer and Chief Financial Officer. For reporting purposes, Corporate and Investments is reflected separately; however, it is not considered an operating segment under these circumstances. Other reconciling items include, but are not limited to, the elimination of certain inter segment revenues and expenses and other items that are not allocated to the operating segments. The following tables summarize the results of our operating segments and “Corporate and Investments”: Three Months Ended September 30, Nine Months Ended September 30, Validus Re Segment Information 2017 2016 2017 2016 Underwriting revenues Gross premiums written $ 153,890 $ 94,741 $ 1,071,409 $ 1,072,219 Reinsurance premiums ceded (40,988 ) (15,967 ) (161,188 ) (111,658 ) Net premiums written 112,902 78,774 910,221 960,561 Change in unearned premiums 154,145 149,705 (184,155 ) (241,129 ) Net premiums earned 267,047 228,479 726,066 719,432 Other insurance related income (loss) 68 58 204 (107 ) Total underwriting revenues 267,115 228,537 726,270 719,325 Underwriting deductions Losses and loss expenses 347,484 98,425 538,323 313,432 Policy acquisition costs 45,422 42,837 133,836 127,660 General and administrative expenses 12,444 17,528 48,550 52,579 Share compensation expenses 2,606 2,695 7,746 8,371 Total underwriting deductions 407,956 161,485 728,455 502,042 Underwriting (loss) income $ (140,841 ) $ 67,052 $ (2,185 ) $ 217,283 Selected ratios Ratio of net to gross premiums written 73.4 % 83.1 % 85.0 % 89.6 % Losses and loss expense ratio 130.1 % 43.1 % 74.1 % 43.6 % Policy acquisition cost ratio 17.0 % 18.7 % 18.4 % 17.7 % General and administrative expense ratio (a) 5.7 % 8.9 % 7.8 % 8.5 % Expense ratio 22.7 % 27.6 % 26.2 % 26.2 % Combined ratio 152.8 % 70.7 % 100.3 % 69.8 % (a) The general and administrative expense ratio includes share compensation expenses. Three Months Ended September 30, Nine Months Ended September 30, Talbot Segment Information 2017 2016 2017 2016 Underwriting revenues Gross premiums written $ 192,883 $ 189,674 $ 702,535 $ 752,058 Reinsurance premiums ceded (36,462 ) (22,877 ) (154,263 ) (137,496 ) Net premiums written 156,421 166,797 548,272 614,562 Change in unearned premiums 23,191 32,258 18,279 (7,166 ) Net premiums earned 179,612 199,055 566,551 607,396 Other insurance related income 692 99 1,512 389 Total underwriting revenues 180,304 199,154 568,063 607,785 Underwriting deductions Losses and loss expenses 178,440 109,860 378,241 319,271 Policy acquisition costs 41,493 46,488 129,074 134,444 General and administrative expenses 23,069 32,333 97,094 109,929 Share compensation expenses 2,310 3,163 8,292 9,955 Total underwriting deductions 245,312 191,844 612,701 573,599 Underwriting (loss) income $ (65,008 ) $ 7,310 $ (44,638 ) $ 34,186 Selected ratios Ratio of net to gross premiums written 81.1 % 87.9 % 78.0 % 81.7 % Losses and loss expense ratio 99.3 % 55.2 % 66.8 % 52.6 % Policy acquisition cost ratio 23.1 % 23.4 % 22.8 % 22.1 % General and administrative expense ratio (a) 14.2 % 17.8 % 18.5 % 19.7 % Expense ratio 37.3 % 41.2 % 41.3 % 41.8 % Combined ratio 136.6 % 96.4 % 108.1 % 94.4 % (a) The general and administrative expense ratio includes share compensation expenses. Three Months Ended September 30, Nine Months Ended September 30, Western World Segment Information 2017 2016 2017 2016 Underwriting revenues Gross premiums written $ 156,517 $ 85,260 $ 459,628 $ 236,190 Reinsurance premiums ceded (43,207 ) (6,202 ) (72,005 ) (15,347 ) Net premiums written 113,310 79,058 387,623 220,843 Change in unearned premiums 61,603 (8,260 ) 15,256 (22,890 ) Net premiums earned 174,913 70,798 402,879 197,953 Other insurance related income 662 219 1,566 696 Total underwriting revenues 175,575 71,017 404,445 198,649 Underwriting deductions Losses and loss expenses 157,709 45,748 329,642 129,623 Policy acquisition costs 20,721 17,094 60,187 46,704 General and administrative expenses 21,553 10,171 50,623 33,704 Share compensation expenses 354 702 1,655 1,825 Total underwriting deductions 200,337 73,715 442,107 211,856 Underwriting (loss) $ (24,762 ) $ (2,698 ) $ (37,662 ) $ (13,207 ) Selected ratios Ratio of net to gross premiums written 72.4 % 92.7 % 84.3 % 93.5 % Losses and loss expense ratio 90.2 % 64.6 % 81.8 % 65.5 % Policy acquisition cost ratio 11.8 % 24.1 % 14.9 % 23.6 % General and administrative expense ratio (a) 12.5 % 15.4 % 13.0 % 17.9 % Expense ratio 24.3 % 39.5 % 27.9 % 41.5 % Combined ratio 114.5 % 104.1 % 109.7 % 107.0 % (a) The general and administrative expense ratio includes share compensation expenses. Three Months Ended September 30, Nine Months Ended September 30, AlphaCat Segment Information 2017 2016 2017 2016 Fee revenues Third party $ 5,095 $ 7,025 $ 15,288 $ 14,843 Related party 457 1,373 1,732 2,592 Total fee revenues 5,552 8,398 17,020 17,435 Expenses General and administrative expenses 2,929 3,324 10,322 7,557 Share compensation expenses 183 (107 ) 348 167 Finance expenses 32 31 107 914 Tax (benefit) expense (65 ) — 69 — Foreign exchange losses 7 5 7 17 Total expenses 3,086 3,253 10,853 8,655 Income before investments from AlphaCat Funds and Sidecars 2,466 5,145 6,167 8,780 Investment (loss) income from AlphaCat Funds and Sidecars (a) AlphaCat Sidecars 201 (72 ) 68 593 AlphaCat ILS Funds - Lower Risk (b) (7,553 ) 2,321 (4,063 ) 6,903 AlphaCat ILS Funds - Higher Risk (b) (21,816 ) 2,479 (16,849 ) 5,607 BetaCat ILS Funds (922 ) 1,303 (291 ) 2,979 PaCRe — — — (23 ) Validus’ share of investment (loss) income from AlphaCat Funds and Sidecars (30,090 ) 6,031 (21,135 ) 16,059 Validus’ share of AlphaCat segment (loss) income $ (27,624 ) $ 11,176 $ (14,968 ) $ 24,839 Supplemental information Gross premiums written AlphaCat Sidecars $ — $ (112 ) $ 66 $ (178 ) AlphaCat ILS Funds - Lower Risk (b) 10,979 2,049 117,519 112,241 AlphaCat ILS Funds - Higher Risk (b) 16,275 1,797 153,483 140,127 AlphaCat Direct (c) (41 ) 679 26,753 18,476 Total gross premiums written $ 27,213 $ 4,413 $ 297,821 $ 270,666 (a) The investment (loss) income from the AlphaCat funds and sidecars is based on equity accounting. (b) Lower risk AlphaCat ILS funds have a maximum permitted portfolio expected loss of less than 7%, whereas higher risk AlphaCat ILS funds have a maximum permitted portfolio expected loss of greater than 7%. Expected loss represents the average annual loss over the set of simulation scenarios divided by the total limit. (c) AlphaCat Direct includes direct investments from third party investors in AlphaCat Re. Three Months Ended September 30, Nine Months Ended September 30, Corporate and Investments 2017 2016 2017 2016 Managed investments Managed net investment income (a) $ 37,091 $ 41,071 $ 111,346 $ 105,843 Net realized gains on managed investments (a) 903 4,080 280 5,514 Change in net unrealized gains on managed investments (a) 941 4,652 31,232 81,782 Income (loss) from investment affiliates 1,011 453 15,665 (4,249 ) Total managed investment return 39,946 50,256 158,523 188,890 Corporate expenses General and administrative expenses 9,539 18,221 45,563 52,276 Share compensation expenses 3,990 4,048 12,039 12,147 Finance expenses (a) 14,449 14,317 42,462 42,637 Dividends on preferred shares 5,627 2,252 10,033 2,252 Tax (benefit) expense (a) (2,567 ) 1,830 (7,237 ) 1,418 Total Corporate expenses 31,038 40,668 102,860 110,730 Other items Foreign exchange (losses) (a) (1,495 ) (1,067 ) (7,715 ) 11,628 Other income (loss) 35 (1,529 ) 303 (773 ) Transaction expenses — — (4,427 ) — Total other items (1,460 ) (2,596 ) (11,839 ) 10,855 Total Corporate and Investments $ 7,448 $ 6,992 $ 43,824 $ 89,015 (a) These items exclude the components which are included in Validus’ share of AlphaCat and amounts which are consolidated from VIEs. The following tables reconcile the results of our operating segments along with our corporate and investments function to the Consolidated results of the Company for the periods indicated: Three Months Ended September 30, 2017 Validus Re Segment Talbot Segment Western World Segment AlphaCat Segment and Consolidated VIEs Corporate and Investments Eliminations Total Underwriting revenues Gross premiums written $ 153,890 $ 192,883 $ 156,517 $ 27,213 $ — $ (6,647 ) $ 523,856 Reinsurance premiums ceded (40,988 ) (36,462 ) (43,207 ) (2,850 ) — 6,647 (116,860 ) Net premiums written 112,902 156,421 113,310 24,363 — — 406,996 Change in unearned premiums 154,145 23,191 61,603 77,273 — — 316,212 Net premiums earned 267,047 179,612 174,913 101,636 — — 723,208 Other insurance related income 68 692 662 6,083 — (3,969 ) 3,536 Total underwriting revenues 267,115 180,304 175,575 107,719 — (3,969 ) 726,744 Underwriting deductions Losses and loss expenses 347,484 178,440 157,709 570,969 — — 1,254,602 Policy acquisition costs 45,422 41,493 20,721 8,314 — (360 ) 115,590 General and administrative expenses 12,444 23,069 21,553 7,687 9,539 (3,950 ) 70,342 Share compensation expenses 2,606 2,310 354 183 3,990 — 9,443 Total underwriting deductions 407,956 245,312 200,337 587,153 13,529 (4,310 ) 1,449,977 Underwriting (loss) $ (140,841 ) $ (65,008 ) $ (24,762 ) $ (479,434 ) $ (13,529 ) $ 341 $ (723,233 ) Net investment return (a) — — — 1,232 39,946 — 41,178 Other items (b) — — — 82 (18,969 ) — (18,887 ) Loss attributable to AlphaCat investors — — — 74,130 — — 74,130 Net loss attributable to noncontrolling interest — — — 376,366 — — 376,366 Segmental (loss) $ (140,841 ) $ (65,008 ) $ (24,762 ) $ (27,624 ) $ 7,448 $ 341 Net loss attributable to Validus common shareholders $ (250,446 ) (a) Net investment return includes net investment income, net realized and change in net unrealized gains (losses) on investments and income (loss) from investment affiliates. (b) Other items includes finance expenses, transaction expenses, dividends on preferred shares, tax benefit (expense), foreign exchange gains (losses), income (loss) from operating affiliate and other income (loss). Three Months Ended September 30, 2016 Validus Re Segment Talbot Segment Western World Segment AlphaCat Segment and Consolidated VIEs Corporate and Investments Eliminations Total Underwriting revenues Gross premiums written $ 94,741 $ 189,674 $ 85,260 $ 4,413 $ — $ (1,670 ) $ 372,418 Reinsurance premiums ceded (15,967 ) (22,877 ) (6,202 ) (1,630 ) — 1,670 (45,006 ) Net premiums written 78,774 166,797 79,058 2,783 — — 327,412 Change in unearned premiums 149,705 32,258 (8,260 ) 62,660 — — 236,363 Net premiums earned 228,479 199,055 70,798 65,443 — — 563,775 Other insurance related income 58 99 219 8,656 — (8,113 ) 919 Total underwriting revenues 228,537 199,154 71,017 74,099 — (8,113 ) 564,694 Underwriting deductions Losses and loss expenses 98,425 109,860 45,748 4,361 — — 258,394 Policy acquisition costs 42,837 46,488 17,094 7,075 — (60 ) 113,434 General and administrative expenses 17,528 32,333 10,171 12,255 18,221 (8,065 ) 82,443 Share compensation expenses 2,695 3,163 702 (107 ) 4,048 — 10,501 Total underwriting deductions 161,485 191,844 73,715 23,584 22,269 (8,125 ) 464,772 Underwriting income (loss) $ 67,052 $ 7,310 $ (2,698 ) $ 50,515 $ (22,269 ) $ 12 $ 99,922 Net investment return (a) — — — 3,567 50,256 — 53,823 Other items (b) — — — 97 (20,995 ) — (20,898 ) (Income) attributable to AlphaCat investors — — — (5,564 ) — — (5,564 ) Net (income) attributable to noncontrolling interest — — — (37,439 ) — — (37,439 ) Segmental income (loss) $ 67,052 $ 7,310 $ (2,698 ) $ 11,176 $ 6,992 $ 12 Net income available to Validus common shareholders $ 89,844 (a) Net investment return includes net investment income, net realized and change in net unrealized gains (losses) on investments and income (loss) from investment affiliates. (b) Other items includes finance expenses, transaction expenses, dividends on preferred shares, tax benefit (expense), foreign exchange gains (losses), income (loss) from operating affiliate and other income (loss). Nine Months Ended September 30, 2017 Validus Re Segment Talbot Segment Western World Segment AlphaCat Segment and Consolidated VIEs Corporate and Investments Eliminations Total Underwriting revenues Gross premiums written $ 1,071,409 $ 702,535 $ 459,628 $ 297,821 $ — $ (23,778 ) $ 2,507,615 Reinsurance premiums ceded (161,188 ) (154,263 ) (72,005 ) (9,510 ) — 23,778 (373,188 ) Net premiums written 910,221 548,272 387,623 288,311 — — 2,134,427 Change in unearned premiums (184,155 ) 18,279 15,256 (54,196 ) — — (204,816 ) Net premiums earned 726,066 566,551 402,879 234,115 — — 1,929,611 Other insurance related income 204 1,512 1,566 17,118 — (14,463 ) 5,937 Total underwriting revenues 726,270 568,063 404,445 251,233 — (14,463 ) 1,935,548 Underwriting deductions Losses and loss expenses 538,323 378,241 329,642 574,130 — — 1,820,336 Policy acquisition costs 133,836 129,074 60,187 22,380 — (991 ) 344,486 General and administrative expenses 48,550 97,094 50,623 27,096 45,563 (14,311 ) 254,615 Share compensation expenses 7,746 8,292 1,655 348 12,039 — 30,080 Total underwriting deductions 728,455 612,701 442,107 623,954 57,602 (15,302 ) 2,449,517 Underwriting (loss) $ (2,185 ) $ (44,638 ) $ (37,662 ) $ (372,721 ) $ (57,602 ) $ 839 $ (513,969 ) Net investment return (a) — — — 12,543 158,523 — 171,066 Other items (b) — — — 269 (57,097 ) — (56,828 ) Loss attributable to AlphaCat investors — — — 54,797 — — 54,797 Net loss attributable to noncontrolling interest — — — 290,144 — — 290,144 Segmental (loss) $ (2,185 ) $ (44,638 ) $ (37,662 ) $ (14,968 ) $ 43,824 $ 839 Net loss attributable to Validus common shareholders $ (54,790 ) (a) Net investment return includes net investment income, net realized and change in net unrealized gains (losses) on investments and income (loss) from investment affiliates. (b) Other items includes finance expenses, transaction expenses, dividends on preferred shares, tax benefit (expense), foreign exchange gains (losses), income (loss) from operating affiliate and other income (loss). Nine Months Ended September 30, 2016 Validus Re Segment Talbot Segment Western World Segment AlphaCat Segment and Consolidated VIEs Corporate and Investments Eliminations Total Underwriting revenues Gross premiums written $ 1,072,219 $ 752,058 $ 236,190 $ 270,666 $ — $ (21,882 ) $ 2,309,251 Reinsurance premiums ceded (111,658 ) (137,496 ) (15,347 ) (6,451 ) — 21,882 (249,070 ) Net premiums written 960,561 614,562 220,843 264,215 — — 2,060,181 Change in unearned premiums (241,129 ) (7,166 ) (22,890 ) (80,230 ) — — (351,415 ) Net premiums earned 719,432 607,396 197,953 183,985 — — 1,708,766 Other insurance related (loss) income (107 ) 389 696 17,722 — (16,300 ) 2,400 Total underwriting revenues 719,325 607,785 198,649 201,707 — (16,300 ) 1,711,166 Underwriting deductions Losses and loss expenses 313,432 319,271 129,623 27,645 — — 789,971 Policy acquisition costs 127,660 134,444 46,704 19,762 — 23 328,593 General and administrative expenses 52,579 109,929 33,704 26,272 52,276 (16,421 ) 258,339 Share compensation expenses 8,371 9,955 1,825 167 12,147 — 32,465 Total underwriting deductions 502,042 573,599 211,856 73,846 64,423 (16,398 ) 1,409,368 Underwriting income (loss) $ 217,283 $ 34,186 $ (13,207 ) $ 127,861 $ (64,423 ) $ 98 $ 301,798 Net investment return (a) — — — 10,558 188,890 (597 ) 198,851 Other items (b) — — — (1,139 ) (35,452 ) — (36,591 ) (Income) attributable to AlphaCat investors — — — (16,278 ) — — (16,278 ) Net (income) attributable to noncontrolling interest — — — (96,163 ) — — (96,163 ) Segmental income (loss) $ 217,283 $ 34,186 $ (13,207 ) $ 24,839 $ 89,015 $ (499 ) Net income available to Validus common shareholders $ 351,617 (a) Net investment return includes net investment income, net realized and change in net unrealized gains (losses) on investments and income (loss) from investment affiliates. (b) Other items includes finance expenses, transaction expenses, dividends on preferred shares, tax benefit (expense), foreign exchange gains (losses), income (loss) from operating affiliate and other income (loss). The Company’s exposures are generally diversified across geographic zones. The following tables set forth the gross premiums written by operating segment allocated to the territory of coverage exposure for the periods indicated: Gross Premiums Written Three Months Ended September 30, 2017 Validus Re Talbot Western World AlphaCat Eliminations Total % United States $ 59,838 $ 24,584 $ 156,517 $ 18,440 $ (6,300 ) $ 253,079 48.3 % Worldwide excluding United States (a) 7,198 43,136 — 712 76 51,122 9.8 % Australia and New Zealand (450 ) 3,696 — — 9 3,255 0.6 % Europe 4,744 5,372 — 149 62 10,327 2.0 % Latin America and Caribbean 19,430 20,726 — — (454 ) 39,702 7.6 % Japan 436 1,165 — — — 1,601 0.3 % Canada 24 1,820 — 458 (6 ) 2,296 0.4 % Rest of the world (b) 1,447 21,478 — — 57 22,982 4.4 % Sub-total, non United States 32,829 97,393 — 1,319 (256 ) 131,285 25.1 % Worldwide including United States (a) 33,724 16,293 — 4,993 (91 ) 54,919 10.5 % Other locations non-specific (c) 27,499 54,613 — 2,461 — 84,573 16.1 % Total $ 153,890 $ 192,883 $ 156,517 $ 27,213 $ (6,647 ) $ 523,856 100.0 % Gross Premiums Written Three Months Ended September 30, 2016 Validus Re Talbot Western World AlphaCat Eliminations Total % United States $ 31,345 $ 19,937 $ 85,260 $ 1,837 $ (76 ) $ 138,303 37.1 % Worldwide excluding United States (a) 4,145 40,058 — (288 ) (39 ) 43,876 11.7 % Australia and New Zealand 57 3,238 — — 6 3,301 0.9 % Europe 4,536 4,957 — — 40 9,533 2.6 % Latin America and Caribbean 17,036 25,173 — — (793 ) 41,416 11.1 % Japan (33 ) 997 — — 7 971 0.3 % Canada 149 2,015 — — (42 ) 2,122 0.6 % Rest of the world (b) 2,360 19,166 — — 66 21,592 5.8 % Sub-total, non United States 28,250 95,604 — (288 ) (755 ) 122,811 33.0 % Worldwide including United States (a) 22,399 12,771 — 2,872 (838 ) 37,204 10.0 % Other locations non-specific (c) 12,747 61,362 — (8 ) (1 ) 74,100 19.9 % Total $ 94,741 $ 189,674 $ 85,260 $ 4,413 $ (1,670 ) $ 372,418 100.0 % Gross Premiums Written Nine Months Ended September 30, 2017 Validus Re Talbot Western World AlphaCat Eliminations Total % United States $ 374,018 $ 88,139 $ 459,628 $ 116,691 $ (10,623 ) $ 1,027,853 41.0 % Worldwide excluding United States (a) 45,803 110,094 — 8,617 (463 ) 164,051 6.6 % Australia and New Zealand 3,745 8,726 — 2,003 (101 ) 14,373 0.6 % Europe 35,108 22,944 — 600 (368 ) 58,284 2.2 % Latin America and Caribbean 40,646 69,703 — 46 (4,737 ) 105,658 4.2 % Japan 40,902 6,371 — 3,855 (36 ) 51,092 2.0 % Canada 4,894 4,068 — 588 (55 ) 9,495 0.4 % Rest of the world (b) 20,229 67,918 — — (1,520 ) 86,627 3.5 % Sub-total, non United States 191,327 289,824 — 15,709 (7,280 ) 489,580 19.5 % Worldwide including United States (a) 189,669 74,385 — 158,239 (5,875 ) 416,418 16.6 % Other locations non-specific (c) 316,395 250,187 — 7,182 — 573,764 22.9 % Total $ 1,071,409 $ 702,535 $ 459,628 $ 297,821 $ (23,778 ) $ 2,507,615 100.0 % Gross Premiums Written Nine Months Ended September 30, 2016 Validus Re Talbot Western World AlphaCat Eliminations Total % United States $ 455,826 $ 85,182 $ 236,190 $ 64,566 $ (1,631 ) $ 840,133 36.4 % Worldwide excluding United States (a) 51,384 105,590 — 22,219 (650 ) 178,543 7.8 % Australia and New Zealand 6,906 7,613 — 4,949 (107 ) 19,361 0.8 % Europe 30,270 25,673 — 3,306 (668 ) 58,581 2.5 % Latin America and Caribbean 36,610 76,577 — — (6,330 ) 106,857 4.6 % Japan 39,892 5,579 — 3,221 (24 ) 48,668 2.1 % Canada 3,646 5,577 — 223 (129 ) 9,317 0.4 % Rest of the world (b) 22,307 76,456 — — (2,276 ) 96,487 4.2 % Sub-total, non United States 191,015 303,065 — 33,918 (10,184 ) 517,814 22.4 % Worldwide including United States (a) 169,737 75,423 — 170,639 (10,052 ) 405,747 17.6 % Other locations non-specific (c) 255,641 288,388 — 1,543 (15 ) 545,557 23.6 % Total $ 1,072,219 $ 752,058 $ 236,190 $ 270,666 $ (21,882 ) $ 2,309,251 100.1 % (a) Represents risks in two or more geographic zones. (b) Represents risks in one geographic zone. (c) The Other locations non-specific category refers to business for which an analysis of exposure by geographic zone is not applicable since these exposures can span multiple geographic areas and, in some instances, are not fixed locations.

Subsequent events

Subsequent events	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent events	Subsequent events California Wildfires The California Wildfires were a series of wildfires that burned across Northern California in October 2017 causing widespread residential and commercial property damage across a number of counties. The Company is presently reviewing its exposure based on in-force contracts and preliminary loss information from clients and anticipates that the California Wildfires will likely be a notable loss event. Dividends On November 1, 2017, the Company announced a quarterly cash dividend of $0.38 per common share, payable on December 29, 2017 to shareholders of record on December 15, 2017. The Company also announced a quarterly cash dividend of $0.3671875 and $0.3625000 per depository share on the outstanding Series A and Series B Preferred Shares, respectively. The Series A and Series B Preferred Share dividends are payable on December 15, 2017 to shareholders of record on December 1, 2017.

Significant accounting policies

Significant accounting policies (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Basis of preparation	These unaudited Consolidated Financial Statements (the “Consolidated Financial Statements”) have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 in Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In addition, the year-end balance sheet data was derived from audited financial statements but does not include all disclosures required by U.S. GAAP. This Quarterly Report on Form 10-Q should be read in conjunction with the financial statements and related notes included in Validus Holdings, Ltd.’s (the “Company”) Annual Report on Form 10-K for the year ended December 31, 2016 , as filed with the U.S. Securities and Exchange Commission (the “SEC”). In the opinion of management, these unaudited Consolidated Financial Statements reflect all adjustments (including normal recurring adjustments) considered necessary for a fair statement of the Company’s financial position and results of operations as at the end of and for the periods presented. All significant intercompany accounts and transactions have been eliminated. The results of operations for any interim period are not necessarily indicative of the results for a full year.
Use of estimates	The preparation of these financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported 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. While management believes that the amounts included in the Consolidated Financial Statements reflect its best estimates and assumptions, actual results could differ materially from those estimates. The Company’s principal estimates include: • reserve for losses and loss expenses; • premium estimates for business written on a line slip or proportional basis; • the valuation of goodwill and intangible assets; • reinsurance recoverable balances including the provision for uncollectible amounts; and • investment valuation of financial assets.
Consolidating voting interest entities and variable interest entities	The Company consolidates in these Consolidated Financial Statements the results of operations and financial position of all voting interest entities (“VOE”) in which the Company has a controlling financial interest and all variable interest entities (“VIE”) in which the Company is considered to be the primary beneficiary. The consolidation assessment, including the determination as to whether an entity qualifies as a VIE or VOE, depends on the facts and circumstances surrounding each entity.

Business combination (Tables)

Business combination (Tables)	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Schedule of fair value of net assets acquired	The fair value of net assets acquired, including GAAP adjustments, are summarized as follows: Total purchase price $ 185,576 Assets acquired Cash and cash equivalents $ 1,653 Premiums receivable 564,453 Prepaid reinsurance premiums 227,157 Other assets 157,146 Assets acquired 950,409 Liabilities acquired Reinsurance balances payable $ 294,201 Unearned premiums 406,649 Net loss reserves 42,575 Other liabilities 122,715 Liabilities acquired 866,140 Excess purchase price $ 101,307 Goodwill and other intangible assets acquired Intangible asset - Distribution channels $ 52,898 Intangible asset - Brand name 9,568 Intangible asset - Technology 1,455 Total intangible assets 63,921 Goodwill 30,943 Deferred tax arising on Goodwill 6,443 Total goodwill and intangible assets $ 101,307
Reconciliation of goodwill and intangible assets	The following tables reconcile the carrying amount of goodwill and intangible assets from December 31, 2016 to September 30, 2017 : Goodwill Nine Months Ended September 30, 2017 Talbot Western World Total Balance at December 31, 2016 $ 20,393 $ 176,365 $ 196,758 Additions — 30,943 30,943 Balance at September 30, 2017 $ 20,393 $ 207,308 $ 227,701 Intangible assets Nine Months Ended September 30, 2017 Talbot Western World Total Balance at December 31, 2016 $ 93,924 $ 21,668 $ 115,592 Additions — 63,921 63,921 Amortization (2,081 ) (4,034 ) (6,115 ) Balance at September 30, 2017 $ 91,843 $ 81,555 $ 173,398 Intangible assets Nine Months Ended September 30, 2017 With a Finite Life With an Indefinite Life Total Balance at December 31, 2016 $ 11,424 $ 104,168 $ 115,592 Additions 63,921 — 63,921 Amortization (6,115 ) — (6,115 ) Balance at September 30, 2017 $ 69,230 $ 104,168 $ 173,398
Supplemental pro forma information	The following selected unaudited information has been provided to present a summary of the results of CRS that have been included in the Consolidated Financial Statements for the three and nine months ended September 30, 2017 . Three Months Ended September 30, 2017 Nine Months Ended September 30, 2017 Net premiums written $ 32,852 $ 39,840 Net premiums earned $ 98,757 $ 148,801 Total underwriting deductions $ 84,826 $ 129,606 Underwriting income, before general and administrative expenses $ 13,931 $ 19,195

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2017
Investments [Abstract]
Amortized cost (or cost), gross unrealized gains and (losses) and fair value of investments	The amortized cost (or cost) and fair value of the Company’s investments as at September 30, 2017 and December 31, 2016 were as follows: September 30, 2017 December 31, 2016 Amortized Amortized Fair Value Managed investments U.S. government and government agency $ 598,607 $ 595,694 $ 809,392 $ 804,126 Non-U.S. government and government agency 288,296 290,538 245,651 240,791 U.S. states, municipalities and political subdivisions 205,880 206,667 271,742 271,830 Agency residential mortgage-backed securities 830,542 828,400 684,490 679,595 Non-agency residential mortgage-backed securities 38,806 38,993 15,858 15,477 U.S. corporate 1,457,073 1,466,739 1,540,036 1,534,508 Non-U.S. corporate 390,519 392,242 418,520 410,227 Bank loans 471,855 464,464 579,121 570,399 Asset-backed securities 520,594 522,524 528,563 526,814 Commercial mortgage-backed securities 315,585 314,221 333,740 330,932 Total fixed maturities 5,117,757 5,120,482 5,427,113 5,384,699 Short-term investments 258,339 258,646 228,574 228,386 Other investments Fund of hedge funds — — 1,457 955 Hedge funds 11,292 19,233 11,292 17,381 Private equity investments 88,299 107,230 66,383 82,627 Fixed income investment funds 282,707 285,034 247,967 249,275 Overseas deposits 55,775 55,775 50,106 50,106 Mutual funds 1,918 4,028 2,925 5,368 Total other investments 439,991 471,300 380,130 405,712 Investments in investment affiliates (a) 60,228 92,079 84,840 100,431 Total managed investments $ 5,876,315 $ 5,942,507 $ 6,120,657 $ 6,119,228 Non-managed investments Catastrophe bonds $ 303,789 $ 299,484 $ 157,486 $ 158,331 Short-term investments 2,734,600 2,734,600 2,567,784 2,567,784 Total non-managed investments 3,038,389 3,034,084 2,725,270 2,726,115 Total investments $ 8,914,704 $ 8,976,591 $ 8,845,927 $ 8,845,343 (a) The Company’s investments in investment affiliates have been treated as equity method investments with the corresponding gains and losses recorded in income as “Income (loss) from investment affiliates.”
Investment ratings on fixed maturities	The following table sets forth certain information regarding the investment ratings of the Company’s fixed maturity investments as at September 30, 2017 and December 31, 2016 . September 30, 2017 December 31, 2016 Fair Value % of Total Fair Value % of Total Managed fixed maturities AAA $ 2,349,803 43.3 % $ 2,405,597 43.4 % AA 437,215 8.1 % 538,289 9.7 % A 1,060,849 19.6 % 1,081,949 19.5 % BBB 752,808 13.9 % 740,861 13.4 % Total investment grade managed fixed maturities 4,600,675 84.9 % 4,766,696 86.0 % BB 177,667 3.2 % 213,568 3.9 % B 156,590 2.9 % 177,737 3.2 % CCC 5,286 0.1 % 13,371 0.2 % NR 180,264 3.4 % 213,327 3.8 % Total non-investment grade fixed maturities 519,807 9.6 % 618,003 11.1 % Total managed fixed maturities $ 5,120,482 94.5 % $ 5,384,699 97.1 % Non-managed catastrophe bonds AAA $ 1,650 0.0 % $ — 0.0 % Total investment grade non-managed fixed maturities 1,650 0.0 % — 0.0 % BB 28,031 0.5 % 29,731 0.6 % B 2,755 0.1 % 4,524 0.1 % NR 267,048 4.9 % 124,076 2.2 % Total non-investment grade non-managed fixed maturities 297,834 5.5 % 158,331 2.9 % Total non-managed fixed maturities 299,484 5.5 % 158,331 2.9 % Total fixed maturities $ 5,419,966 100.0 % $ 5,543,030 100.0 %
Fixed maturities investments by contractual maturity	The amortized cost and fair value amounts for the Company’s fixed maturity investments held at September 30, 2017 and December 31, 2016 are shown below by contractual maturity. Actual maturity may differ from contractual maturity because certain borrowers may have the right to call or prepay certain obligations with or without call or prepayment penalties. September 30, 2017 December 31, 2016 Amortized Cost Fair Value Amortized Cost Fair Value Managed fixed maturities Due in one year or less $ 279,069 $ 278,118 $ 350,733 $ 346,161 Due after one year through five years 2,418,737 2,416,963 2,954,856 2,933,146 Due after five years through ten years 534,922 535,538 430,365 426,647 Due after ten years 179,502 185,725 128,508 125,927 3,412,230 3,416,344 3,864,462 3,831,881 Asset-backed and mortgage-backed securities 1,705,527 1,704,138 1,562,651 1,552,818 Total managed fixed maturities $ 5,117,757 $ 5,120,482 $ 5,427,113 $ 5,384,699 Non-managed catastrophe bonds Due in one year or less $ 88,949 $ 88,202 $ 43,664 $ 45,418 Due after one year through five years 209,340 206,117 112,572 111,656 Due after five years through ten years 5,500 5,165 1,250 1,257 Total non-managed fixed maturities 303,789 299,484 157,486 158,331 Total fixed maturities $ 5,421,546 $ 5,419,966 $ 5,584,599 $ 5,543,030
Other investments	The following tables set forth certain information regarding the Company’s other investment portfolio as at September 30, 2017 and December 31, 2016 : September 30, 2017 Fair Value Investments with redemption restrictions Investments without redemption restrictions Redemption frequency (a) Redemption notice period (a) Hedge funds 19,233 19,233 — Private equity investments 107,230 107,230 — Fixed income investment funds 285,034 249,999 35,035 Daily Daily to 2 days Overseas deposits 55,775 55,775 — Mutual funds 4,028 — 4,028 Daily Daily Total other investments $ 471,300 $ 432,237 $ 39,063 December 31, 2016 Fair Value Investments with redemption restrictions Investments without redemption restrictions Redemption frequency (a) Redemption notice period (a) Fund of hedge funds $ 955 $ 955 $ — Hedge funds 17,381 17,381 — Private equity investments 82,627 82,627 — Fixed income investment funds 249,275 218,333 30,942 Daily 2 days Overseas deposits 50,106 50,106 — Mutual funds 5,368 — 5,368 Daily Daily Total other investments $ 405,712 $ 369,402 $ 36,310 (a) The redemption frequency and notice periods only apply to investments without redemption restrictions.
Reconciliation of beginning and ending investment in affiliate balances	The following table presents a reconciliation of the Company’s beginning and ending investments in investment affiliates for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Investments in investment affiliates, beginning of period $ 103,377 $ 99,278 $ 100,431 $ 87,673 Net capital (distributions) contributions (12,309 ) — (24,017 ) 16,307 Income (loss) from investment affiliates 1,011 453 15,665 (4,249 ) Investments in investment affiliates, end of period $ 92,079 $ 99,731 $ 92,079 $ 99,731
Schedule of equity method investments	The following table presents the Company’s investments in investment affiliates as at September 30, 2017 and December 31, 2016 : September 30, 2017 Investment at cost Voting ownership % Equity ownership % Carrying value Aquiline II $ 33,349 — % 8.1 % $ 50,695 Aquiline III 24,737 — % 9.0 % 39,530 Aquiline Tech 2,142 — % 10.6 % 1,854 Total investments in investment affiliates $ 60,228 $ 92,079 December 31, 2016 Investment at cost Voting ownership % Equity ownership % Carrying value Aquiline II $ 46,871 — % 8.1 % $ 61,999 Aquiline III 37,969 — % 9.0 % 38,432 Total investments in investment affiliates $ 84,840 $ 100,431
Net investment income	Net investment income was derived from the following sources: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Managed investments Fixed maturities and short-term investments $ 30,823 $ 30,572 $ 93,706 $ 89,210 Other investments 7,391 11,768 21,832 20,666 Cash and cash equivalents and restricted cash 1,230 891 2,556 2,136 Securities lending income 3 22 23 39 Total gross investment income 39,447 43,253 118,117 112,051 Investment expenses (2,356 ) (2,182 ) (6,771 ) (6,208 ) Total managed net investment income $ 37,091 $ 41,071 $ 111,346 $ 105,843 Non managed investments Fixed maturities and short-term investments $ 3,941 $ 1,970 $ 11,501 $ 5,242 Restricted cash, cash and cash equivalents 3,426 473 6,066 1,147 Total non-managed net investment income 7,367 2,443 17,567 6,389 Total net investment income $ 44,458 $ 43,514 $ 128,913 $ 112,232
Analysis of net realized gains and the change in net unrealized gains (losses) on investments	The following table sets forth an analysis of net realized gains and the change in net unrealized (losses) gains on investments: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Managed fixed maturities, short-term and other investments Gross realized gains $ 5,170 $ 4,544 $ 13,035 $ 11,067 Gross realized (losses) (4,267 ) (464 ) (12,755 ) (5,553 ) Net realized gains on investments 903 4,080 280 5,514 Change in net unrealized gains on investments 941 4,652 31,232 81,782 Total net realized and change in net unrealized gains on managed investments $ 1,844 $ 8,732 $ 31,512 $ 87,296 Non-managed fixed maturities and short-term investments Gross realized gains $ 3 $ 317 $ 1,736 $ 1,032 Gross realized (losses) — — — (9 ) Net realized gains on investments 3 317 1,736 1,023 Change in net unrealized (losses) gains on investments (6,138 ) 807 (6,760 ) 2,549 Total net realized and change in net unrealized (losses) gains on non-managed investments (6,135 ) 1,124 (5,024 ) 3,572 Total net realized and change in net unrealized (losses) gains on total investments $ (4,291 ) $ 9,856 $ 26,488 $ 90,868

Fair value measurements (Tables

Fair value measurements (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair value hierarchy - allocation of investments	At September 30, 2017 , the Company’s investments were allocated between Levels 1, 2 and 3 as follows: Level 1 Level 2 Level 3 Fair value based on NAV practical expedient (a) Total Managed investments U.S. government and government agency $ — $ 595,694 $ — $ — $ 595,694 Non-U.S. government and government agency — 290,538 — — 290,538 U.S. states, municipalities and political subdivisions — 206,667 — — 206,667 Agency residential mortgage-backed securities — 828,400 — — 828,400 Non-agency residential mortgage-backed securities — 38,993 — — 38,993 U.S. corporate — 1,466,739 — — 1,466,739 Non-U.S. corporate — 392,242 — — 392,242 Bank loans — 240,563 223,901 — 464,464 Asset-backed securities — 486,537 35,987 — 522,524 Commercial mortgage-backed securities — 314,221 — — 314,221 Total fixed maturities — 4,860,594 259,888 — 5,120,482 Short-term investments 251,578 7,068 — — 258,646 Other investments Hedge funds — — — 19,233 19,233 Private equity investments — — — 107,230 107,230 Fixed income investment funds — 35,145 16,886 233,003 285,034 Overseas deposits — — — 55,775 55,775 Mutual funds — 4,028 — — 4,028 Total other investments — 39,173 16,886 415,241 471,300 Investments in investment affiliates (b) — — — — 92,079 Total managed investments $ 251,578 $ 4,906,835 $ 276,774 $ 415,241 $ 5,942,507 Non-managed investments Catastrophe bonds $ — $ 230,775 $ 68,709 $ — $ 299,484 Short-term investments 2,734,600 — — — 2,734,600 Total non-managed investments 2,734,600 230,775 68,709 — 3,034,084 Total investments $ 2,986,178 $ 5,137,610 $ 345,483 $ 415,241 $ 8,976,591 (a) In accordance with ASC Topic 820 “Fair Value Measurements,” investments measured at fair value using the net asset value (“NAV”) per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. (b) In accordance with ASC Topic 825 “Financial Instruments,” the Company’s investments in investment affiliates have not been classified in the fair value hierarchy. At December 31, 2016 , the Company’s investments were allocated between Levels 1, 2 and 3 as follows: Level 1 Level 2 Level 3 Fair value based on NAV practical expedient (a) Total Managed investments U.S. government and government agency $ — $ 804,126 $ — $ — $ 804,126 Non-U.S. government and government agency — 240,791 — — 240,791 U.S. states, municipalities and political subdivisions — 271,830 — — 271,830 Agency residential mortgage-backed securities — 679,595 — — 679,595 Non-agency residential mortgage-backed securities — 15,477 — — 15,477 U.S. corporate — 1,534,508 — — 1,534,508 Non-U.S. corporate — 410,227 — — 410,227 Bank loans — 323,903 246,496 — 570,399 Asset-backed securities — 502,883 23,931 — 526,814 Commercial mortgage-backed securities — 330,932 — — 330,932 Total fixed maturities — 5,114,272 270,427 — 5,384,699 Short-term investments 209,651 18,735 — — 228,386 Other investments Fund of hedge funds — — — 955 955 Hedge funds — — — 17,381 17,381 Private equity investments — — — 82,627 82,627 Fixed income investment funds — 30,941 12,168 206,166 249,275 Overseas deposits — — — 50,106 50,106 Mutual funds — 5,368 — — 5,368 Total other investments — 36,309 12,168 357,235 405,712 Investments in investment affiliates (b) — — — — 100,431 Total managed investments $ 209,651 $ 5,169,316 $ 282,595 $ 357,235 $ 6,119,228 Non-managed investments Catastrophe bonds $ — $ 109,956 $ 48,375 $ — $ 158,331 Short-term investments 2,567,784 — — — 2,567,784 Total non-managed investments 2,567,784 109,956 48,375 — 2,726,115 Total investments $ 2,777,435 $ 5,279,272 $ 330,970 $ 357,235 $ 8,845,343 (a) In accordance with ASC Topic 820 “Fair Value Measurements,” investments measured at fair value using the net asset value (“NAV”) per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. (b) In accordance with ASC Topic 825 “Financial Instruments,” the Company’s investments in investment affiliates have not been classified in the fair value hierarchy.
Reconciliation of beginning and ending balances for all Level 3 investments measured at fair value on recurring basis	The following table presents a reconciliation of the beginning and ending balances for all investments measured at fair value on a recurring basis using Level 3 inputs during the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, 2017 Bank Loans Catastrophe Bonds Fixed Income Investment Funds Asset Backed Securities Total Level 3 investments, beginning of period $ 224,172 $ 68,025 $ 16,400 $ 35,921 $ 344,518 Purchases 31,312 — — — 31,312 Sales — — — (71 ) (71 ) Settlements (29,796 ) (1,000 ) 486 — (30,310 ) Change in net unrealized (losses) gains (1,787 ) 1,684 — 137 34 Level 3 investments, end of period $ 223,901 $ 68,709 $ 16,886 $ 35,987 $ 345,483 Three Months Ended September 30, 2016 Bank Loans Catastrophe Bonds Asset Backed Securities Total Level 3 investments, beginning of period $ 243,148 $ 37,518 $ 12,383 $ 293,049 Purchases 21,256 — 11,513 32,769 Sales (12,388 ) — — (12,388 ) Change in net unrealized gains 484 517 — 1,001 Level 3 investments, end of period $ 252,500 $ 38,035 $ 23,896 $ 314,431 Nine Months Ended September 30, 2017 Bank Loans Catastrophe Bonds Fixed Income Investment Funds Asset Backed Securities Total Level 3 investments—beginning of period $ 246,496 $ 48,375 $ 12,168 $ 23,931 $ 330,970 Purchases 71,245 66,091 3,432 11,053 151,821 Sales — — — (124 ) (124 ) Settlements (91,799 ) (49,996 ) 1,286 — (140,509 ) Net realized gains — 3,350 — — 3,350 Change in net unrealized (losses) gains (2,041 ) 889 — 1,127 (25 ) Level 3 investments—end of period $ 223,901 $ 68,709 $ 16,886 $ 35,987 $ 345,483 Nine Months Ended September 30, 2016 Bank Loans Catastrophe Bonds Asset Backed Securities Total Level 3 investments—beginning of period $ 232,337 $ 13,500 $ — $ 245,837 Purchases 72,244 23,272 23,896 119,412 Sales (14,777 ) — — (14,777 ) Settlements (34,033 ) (125 ) — (34,158 ) Change in net unrealized (losses) gains (3,271 ) 1,388 — (1,883 ) Level 3 investments—end of period $ 252,500 $ 38,035 $ 23,896 $ 314,431

Variable interest entities (Tab

Variable interest entities (Tables)	9 Months Ended
	Sep. 30, 2017
Variable Interest Entities Disclosure [Abstract]
Summary of notes payable to variable interest entities	The following tables present a reconciliation of the beginning and ending notes payable to AlphaCat investors for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, 2017 Variable Funding Notes Structured Notes Total Notes payable to AlphaCat investors, beginning of period $ 893,959 $ 172,200 $ 1,066,159 Issuance of notes payable to AlphaCat investors 59,530 — 59,530 Redemption of notes payable to AlphaCat investors (18,627 ) — (18,627 ) Foreign exchange losses 556 — 556 Notes payable to AlphaCat investors, end of period $ 935,418 $ 172,200 $ 1,107,618 Three Months Ended September 30, 2016 Variable Funding Notes Structured Notes Total Notes payable to AlphaCat investors, beginning of period $ 276,656 $ 94,326 $ 370,982 Issuance of notes payable to AlphaCat investors 13,808 — 13,808 Redemption of notes payable to AlphaCat investors (12,028 ) — (12,028 ) Foreign exchange gains (32 ) — (32 ) Notes payable to AlphaCat investors, end of period $ 278,404 $ 94,326 $ 372,730 Nine Months Ended September 30, 2017 Variable Funding Notes Structured Notes Total Notes payable to AlphaCat investors, beginning of period $ 278,202 $ — $ 278,202 Notes payable to AlphaCat investors recognized on deconsolidation of AlphaCat ILS fund 423,269 — 423,269 Issuance of notes payable to AlphaCat investors 601,407 172,200 773,607 Redemption of notes payable to AlphaCat investors (367,733 ) — (367,733 ) Foreign exchange losses 273 — 273 Notes payable to AlphaCat investors, end of period $ 935,418 $ 172,200 $ 1,107,618 Nine Months Ended September 30, 2016 Variable Funding Notes Structured Notes Total Notes payable to AlphaCat investors, beginning of period $ 75,493 $ — $ 75,493 Issuance of notes payable to AlphaCat investors 311,913 94,326 406,239 Redemption of notes payable to AlphaCat investors (109,712 ) — (109,712 ) Foreign exchange losses 710 — 710 Notes payable to AlphaCat investors, end of period $ 278,404 $ 94,326 $ 372,730
Total assets and liabilities of the Company's consolidated VIEs	The following table presents the total assets and total liabilities of the Company’s consolidated VIEs, excluding intercompany eliminations, as at September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 Total Assets Total Liabilities Total Assets Total Liabilities AlphaCat sidecars $ 30,598 $ 3,708 $ 40,041 $ 3,206 AlphaCat ILS funds - Lower Risk (a) 1,019,072 234,192 1,498,276 42,457 AlphaCat ILS funds - Higher Risk (a) 947,135 541,466 972,633 381,332 AlphaCat Re and AlphaCat Master Fund 3,427,625 3,427,455 2,510,415 2,510,245 BetaCat ILS funds 144,766 291 82,471 30,663 (a) Lower risk AlphaCat ILS funds have a maximum permitted portfolio expected loss of less than 7%, whereas higher risk AlphaCat ILS funds have a maximum permitted portfolio expected loss of greater than 7%. Expected loss represents the average annual loss over the set of simulation scenarios divided by the total limit.

Noncontrolling interest (Tables

Noncontrolling interest (Tables)	9 Months Ended
	Sep. 30, 2017
Noncontrolling Interest [Abstract]
Reconciliation of beginning and ending balances of noncontrolling interest and redeemable noncontrolling interest	The following tables present a reconciliation of the beginning and ending balances of redeemable noncontrolling interests and noncontrolling interests for the three and nine months ended September 30, 2017 and 2016 : Redeemable noncontrolling interests Noncontrolling interests Total Three Months Ended September 30, Three Months Ended September 30, Three Months Ended September 30, 2017 2016 2017 2016 2017 2016 Balance, beginning of period $ 1,251,660 $ 1,532,283 $ 415,658 $ 212,154 $ 1,667,318 $ 1,744,437 Issuance of shares 26,999 700 — — 26,999 700 (Loss) income attributable to noncontrolling interests (140,781 ) 26,597 (235,585 ) 10,842 (376,366 ) 37,439 Redemption of shares / distributions (3,998 ) — (101,126 ) — (105,124 ) — Balance, end of period $ 1,133,880 $ 1,559,580 $ 78,947 $ 222,996 $ 1,212,827 $ 1,782,576 Redeemable noncontrolling interests Noncontrolling interests Total Nine Months Ended September 30, Nine Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 2017 2016 Balance, beginning of period $ 1,528,001 $ 1,111,714 $ 165,977 $ 154,662 $ 1,693,978 $ 1,266,376 Issuance of shares 237,199 381,950 258,300 171,674 495,499 553,624 Adjustment to noncontrolling interests as a result of deconsolidation (459,021 ) — — — (459,021 ) — (Loss) income attributable to noncontrolling interests (86,296 ) 72,400 (203,848 ) 23,763 (290,144 ) 96,163 Redemption of shares / distributions (86,003 ) (6,484 ) (141,482 ) (127,103 ) (227,485 ) (133,587 ) Balance, end of period $ 1,133,880 $ 1,559,580 $ 78,947 $ 222,996 $ 1,212,827 $ 1,782,576

Derivative instruments (Tables)

Derivative instruments (Tables)	9 Months Ended
	Sep. 30, 2017
Derivative [Line Items]
Location and amount of gains and losses related to derivative instruments reported on in the comprehensive income and earnings	The following table provides the total impact on other comprehensive income (loss) and earnings relating to the derivative instruments formally designated as cash flow hedges along with the impact of the related hedged items for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, Interest rate swap contracts 2017 2016 2017 2016 Amount of effective portion recognized in other comprehensive income $ 1,918 $ 3,155 $ 6,294 $ 9,505 Amount of effective portion subsequently reclassified to earnings $ (1,931 ) $ (2,717 ) $ (6,261 ) $ (8,373 ) Amount of ineffective portion excluded from effectiveness testing $ 13 $ (438 ) $ (33 ) $ (1,132 )
Not designated as hedging instruments
Derivative [Line Items]
Location and fair value amount of derivative instruments reported on the balance sheet	The following table summarizes information on the classification and amount of the fair value of derivatives not designated as hedging instruments for accounting purposes within the Company’s Consolidated Balance Sheets as at September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 Derivatives not designated as hedging instruments Notional Exposure Asset Derivative at Fair Value (a) Liability Derivative at Fair Value (a) Notional Exposure Asset Derivative at Fair Value (a) Liability Derivative at Fair Value (a) Foreign currency forward contracts $ 267,206 $ 1,522 $ 1,379 $ 181,375 $ 2,351 $ 3,421 Interest rate swap contracts $ 200,000 $ 440 $ 1,607 $ — $ — $ — (a) Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses, respectively, within the Company’s consolidated balance sheets.
Location and amount of gains and losses related to derivative instruments reported on in the income statement	The following table summarizes information on the classification and net impact on earnings, recognized in the Company’s Consolidated Statements of Income and Comprehensive Income relating to the foreign currency forward and interest rate swap contracts that were not designated as hedging instruments for accounting purposes during the three and nine months ended September 30, 2017 and 2016 : Derivatives not designated as hedging instruments Classification of (losses) gains recognized in earnings Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Foreign currency forward contracts Foreign exchange (losses) gains $ (1,927 ) $ 1,326 $ (7,999 ) $ 209 Foreign currency forward contracts Other loss $ — $ (155 ) $ (979 ) $ (35 ) Interest rate swap contracts Change in unrealized (losses) gains on investments $ (848 ) $ 566 $ (1,167 ) $ 566
Designated as hedging instruments
Derivative [Line Items]
Location and fair value amount of derivative instruments reported on the balance sheet	The following table summarizes information on the classification and amount of the fair value of derivatives designated as hedging instruments for accounting purposes on the Consolidated Balance Sheets as at September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 Derivatives designated as hedging instruments Notional Exposure Asset Derivative at Fair Value (a) Liability Derivative at Fair Value (a) Notional Exposure Asset Derivative at Fair Value (a) Liability Derivative at Fair Value (a) Interest rate swap contracts $ 552,263 $ 20 $ 1,347 $ 552,263 $ 20 $ 1,479 (a) Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses, respectively, within the Company’s consolidated balance sheets.

Reserve for losses and loss e33

Reserve for losses and loss expenses (Tables)	9 Months Ended
	Sep. 30, 2017
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]
Summary of reserve for losses and loss expenses	The following table summarizes the total reserve for losses and loss expenses as at September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 Case reserves $ 1,271,580 $ 1,237,772 IBNR 3,664,057 1,757,423 Total reserve for losses and loss expenses $ 4,935,637 $ 2,995,195
Reserve for losses and loss expenses	The following table represents an analysis of paid and unpaid losses and loss expenses incurred and a reconciliation of the beginning and ending unpaid losses and loss expenses for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Reserve for losses and loss expenses, beginning of period $ 3,305,191 $ 3,122,717 $ 2,995,195 $ 2,996,567 Loss reserves recoverable (600,207 ) (442,987 ) (430,421 ) (350,586 ) Net reserves for losses and loss expenses, beginning of period 2,704,984 2,679,730 2,564,774 2,645,981 Net reserves acquired (a) — — 23,753 — Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in: Current year 1,329,666 311,279 1,999,921 959,376 Prior years (75,064 ) (52,885 ) (179,585 ) (169,405 ) Total net incurred losses and loss expenses 1,254,602 258,394 1,820,336 789,971 Less net losses and loss expenses paid in respect of losses occurring in: Current year (191,612 ) (178,707 ) (242,068 ) (240,362 ) Prior years (181,094 ) (166,539 ) (612,448 ) (596,618 ) Total net paid losses (372,706 ) (345,246 ) (854,516 ) (836,980 ) Foreign exchange losses (gains) 13,741 (1,500 ) 46,274 (7,594 ) Net reserve for losses and loss expenses, end of period 3,600,621 2,591,378 3,600,621 2,591,378 Loss reserves recoverable 1,335,016 444,609 1,335,016 444,609 Reserve for losses and loss expenses, end of period $ 4,935,637 $ 3,035,987 $ 4,935,637 $ 3,035,987 (a) Equals net reserves acquired of $42,575 less net reserves commuted at closing of $18,822 . Incurred losses and loss expenses comprise: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Gross losses and loss expenses $ 2,104,914 $ 284,413 $ 2,866,722 $ 952,129 Reinsurance recoverable (850,312 ) (26,019 ) (1,046,386 ) (162,158 ) Net incurred losses and loss expenses $ 1,254,602 $ 258,394 $ 1,820,336 $ 789,971
Prior year development by segment and line of business	The net favorable development on prior years by segment and line of business for the three and nine months ended September 30, 2017 and 2016 was as follows: Three Months Ended September 30, 2017 Property Marine Specialty Liability Total Validus Re $ (26,372 ) $ (7,105 ) $ (14,660 ) $ — $ (48,137 ) Talbot (8,752 ) (2,737 ) (12,125 ) — (23,614 ) Western World 464 — — (526 ) (62 ) AlphaCat (1,471 ) — (1,780 ) — (3,251 ) Net favorable development $ (36,131 ) $ (9,842 ) $ (28,565 ) $ (526 ) $ (75,064 ) The net favorable loss reserve development on prior accident years of $75.1 million during the three months ended September 30, 2017 included favorable development on loss events and attritional losses of $16.1 million and $58.9 million , respectively. Three Months Ended September 30, 2016 Property Marine Specialty Liability Total Validus Re $ (19,736 ) $ (8,504 ) $ (4,793 ) $ — $ (33,033 ) Talbot (2,429 ) (4,547 ) (11,715 ) — (18,691 ) Western World (553 ) — — (327 ) (880 ) AlphaCat (265 ) — (16 ) — (281 ) Net favorable development $ (22,983 ) $ (13,051 ) $ (16,524 ) $ (327 ) $ (52,885 ) The net favorable loss reserve development on prior accident years of $52.9 million during the three months ended September 30, 2016 included favorable development on loss events and attritional losses of $20.3 million and $32.6 million , respectively. Nine Months Ended September 30, 2017 Property Marine Specialty Liability Total Validus Re $ (30,614 ) $ (38,847 ) $ (30,555 ) $ — $ (100,016 ) Talbot (19,980 ) (35,789 ) (12,535 ) — (68,304 ) Western World (2,838 ) — — 2,094 (744 ) AlphaCat (8,963 ) — (1,558 ) — (10,521 ) Net (favorable) adverse development $ (62,395 ) $ (74,636 ) $ (44,648 ) $ 2,094 $ (179,585 ) The net favorable loss reserve development on prior accident years of $179.6 million during the nine months ended September 30, 2017 included favorable development on loss events and attritional losses of $31.5 million and $148.0 million , respectively. Nine Months Ended September 30, 2016 Property Marine Specialty Liability Total Validus Re $ (52,036 ) $ (14,967 ) $ (22,591 ) $ — $ (89,594 ) Talbot (30,969 ) (10,511 ) (28,259 ) — (69,739 ) Western World (2,576 ) — — (5,888 ) (8,464 ) AlphaCat (742 ) — (866 ) — (1,608 ) Net favorable development $ (86,323 ) $ (25,478 ) $ (51,716 ) $ (5,888 ) $ (169,405 ) The net favorable development on prior accident years of $169.4 million during the nine months ended September 30, 2016

Reinsurance (Tables)

Reinsurance (Tables)	9 Months Ended
	Sep. 30, 2017
Reinsurance Disclosures [Abstract]
Schedule of reinsurance recoverable	The Company’s reinsurance balances recoverable at September 30, 2017 and December 31, 2016 were as follows: September 30, 2017 December 31, 2016 Loss reserves recoverable on unpaid: Case reserves $ 207,368 $ 165,328 IBNR 1,127,648 265,093 Total loss reserves recoverable 1,335,016 430,421 Paid losses recoverable 77,730 35,247 Total reinsurance balances recoverable $ 1,412,746 $ 465,668
Reinsurance recoverables by reinsurer	Reinsurance balances recoverable by reinsurer as at September 30, 2017 and December 31, 2016 were as follows: September 30, 2017 December 31, 2016 Reinsurance Recoverable % of Total Reinsurance Recoverable % of Total Top 10 reinsurers $ 1,208,003 85.5 % $ 395,308 84.9 % Other reinsurers’ balances > $1 million 198,774 14.1 % 66,944 14.4 % Other reinsurers’ balances < $1 million 5,969 0.4 % 3,416 0.7 % Total $ 1,412,746 100.0 % $ 465,668 100.0 % The following tables show the reinsurance balances recoverable due from, and the ratings associated with, the Company’s top ten reinsurers as at September 30, 2017 and December 31, 2016 : September 30, 2017 Top 10 Reinsurers Rating Reinsurance Recoverable % of Total Fully collateralized reinsurers NR $ 564,714 40.0 % Munich Re AA- 164,131 11.6 % Everest Re A+ 95,759 6.8 % Lloyd's Syndicates A+ 94,845 6.7 % Swiss Re AA- 81,921 5.8 % Hannover Re AA- 62,715 4.4 % Federal Crop Insurance Corporation (a) 49,503 3.5 % Qatar Insurance Company A 38,061 2.7 % Transatlantic Re A+ 29,795 2.1 % XL Catlin A+ 26,559 1.9 % Total $ 1,208,003 85.5 % (a) The Company participates in a crop reinsurance program sponsored by the U.S. federal government. The Company remains obligated for amounts ceded in the event that its reinsurers or retrocessionaires do not meet their obligations, except for amounts ceded to the U.S. federal government in the agriculture line of business. December 31, 2016 Top 10 Reinsurers Rating Reinsurance Recoverable % of Total Lloyd's Syndicates A+ $ 84,419 18.2 % Swiss Re AA- 84,044 18.1 % Fully collateralized reinsurers NR 83,088 17.8 % Hannover Re AA- 50,603 10.9 % Everest Re A+ 36,912 7.9 % Munich Re AA- 18,214 3.9 % Transatlantic Re A+ 10,593 2.3 % Hamilton Re A- 10,343 2.2 % Toa Re A+ 9,510 2.0 % National Indemnity Company AA+ 7,582 1.6 % Total $ 395,308 84.9 %

Share capital (Tables)

Share capital (Tables)	9 Months Ended
	Sep. 30, 2017
Stockholders' Equity Note [Abstract]
Summary of preferred shares issued and outstanding	The following table is a summary of the preferred share activity during the nine months ended September 30, 2017 and 2016 : Nine Months Ended September 30, 2017 2016 Preferred shares issued and outstanding, beginning of period 6,000 — Preferred shares issued 10,000 6,000 Preferred shares issued and outstanding, end of period 16,000 6,000
Summary of common shares issued and outstanding	The following table is a summary of the common share activity during the nine months ended September 30, 2017 and 2016 : Nine Months Ended September 30, 2017 2016 Common shares issued, beginning of period 161,279,976 160,570,772 Restricted share awards vested, net of shares withheld 619,046 608,024 Restricted share units vested, net of shares withheld 15,454 18,486 Options exercised — 27,983 Performance share awards vested, net of shares withheld 42,410 48,088 Common shares issued, end of period 161,956,886 161,273,353 Treasury shares, end of period (82,499,633 ) (81,830,323 ) Common shares outstanding, end of period 79,457,253 79,443,030

Stock plans (Tables)

Stock plans (Tables)	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Options, activity during the period	Activity with respect to options for the nine months ended September 30, 2017 and 2016 was as follows: Nine Months Ended September 30, 2017 2016 Options Weighted Average Grant Date Fair Value Weighted Average Grant Date Exercise Price Options Weighted Average Grant Date Fair Value Weighted Average Grant Date Exercise Price Options outstanding, beginning of period 26,136 $ 6.78 $ 23.48 65,401 $ 7.74 $ 20.17 Options exercised — — — (35,351 ) 8.16 17.82 Options outstanding, end of period 26,136 $ 6.78 $ 23.48 30,050 $ 7.24 $ 22.93
Restricted shares awards, activity during the period	Activity with respect to unvested restricted share awards for the nine months ended September 30, 2017 and 2016 was as follows: Nine Months Ended September 30, 2017 2016 Restricted Share Awards Weighted Average Grant Date Fair Value Restricted Share Awards Weighted Average Grant Date Fair Value Restricted share awards outstanding, beginning of period 2,469,982 $ 40.89 2,739,446 $ 38.25 Restricted share awards granted 508,186 53.25 559,516 48.78 Restricted share awards vested (828,800 ) 41.25 (789,547 ) 37.36 Restricted share awards forfeited (53,775 ) 43.38 (33,070 ) 40.25 Restricted share awards outstanding, end of period 2,095,593 $ 43.69 2,476,345 $ 40.88
Restricted share units, activity during the period	Activity with respect to unvested restricted share units for the nine months ended September 30, 2017 and 2016 was as follows: Nine Months Ended September 30, 2017 2016 Restricted Share Units Weighted Average Grant Date Fair Value Restricted Share Units Weighted Average Grant Date Fair Value Restricted share units outstanding, beginning of period 112,808 $ 40.95 114,337 $ 38.47 Restricted share units granted 12,236 53.40 21,609 48.83 Restricted share units vested (18,748 ) 41.91 (23,982 ) 38.18 Restricted share units issued in lieu of cash dividends 2,260 41.42 2,436 39.10 Restricted share units forfeited — — (8,338 ) 44.34 Restricted share units outstanding, end of period 108,556 $ 42.20 106,062 $ 40.20
Performance share awards, activity during the period	Activity with respect to unvested performance share awards for the nine months ended September 30, 2017 and 2016 was as follows: Nine Months Ended September 30, 2017 2016 Performance Share Awards Weighted Average Grant Date Fair Value Performance Share Awards Weighted Average Grant Date Fair Value Performance share awards outstanding, beginning of period 285,820 $ 44.53 172,594 $ 40.70 Performance share awards granted 107,209 53.40 125,290 48.75 Performance share awards vested (52,639 ) 37.33 (57,581 ) 36.11 Performance share awards conversion adjustment (26,322 ) 36.82 45,517 36.82 Performance share awards outstanding, end of period 314,068 $ 49.37 285,820 $ 44.53
Total share compensation expenses	The breakdown of share compensation expenses by award type for the periods indicated was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Restricted share awards $ 7,814 $ 9,159 $ 26,603 $ 27,805 Restricted share units 340 290 982 978 Performance share awards 1,289 1,052 2,495 3,682 Total $ 9,443 $ 10,501 $ 30,080 $ 32,465

Debt and financing arrangemen37

Debt and financing arrangements (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Summary of outstanding debentures and senior notes payable	The Company’s outstanding debentures and senior notes payable as at September 30, 2017 and December 31, 2016 were as follows: September 30, 2017 December 31, 2016 Deferrable debentures 2006 Junior Subordinated $ 150,000 $ 150,000 2007 Junior Subordinated 139,800 139,800 Flagstone 2006 Junior Subordinated 135,360 133,676 Flagstone 2007 Junior Subordinated 113,750 113,750 Total debentures payable 538,910 537,226 2010 Senior notes payable 250,000 250,000 Less: Unamortized debt issuance costs (4,487 ) (4,638 ) Total senior notes payable 245,513 245,362 Total debentures and senior notes payable $ 784,423 $ 782,588
Summary of key terms of debentures and senior notes	The following table summarizes the key terms of the Company’s senior notes and junior subordinated deferrable debentures: Description Issuance date Issued Maturity date Interest Rate as at Interest payments due Issuance Date September 30, 2017 2006 Junior Subordinated Deferrable Debentures June 15, 2006 $ 150,000 June 15, 2036 9.069 % (a) 5.831 % (e) Quarterly Flagstone 2006 Junior Subordinated Deferrable Debentures August 23, 2006 $ 135,360 September 15, 2036 3.540 % (b) 6.463 % (e) Quarterly 2007 Junior Subordinated Deferrable Debentures June 21, 2007 $ 200,000 June 15, 2037 8.480 % (c) 5.180 % (e) Quarterly Flagstone 2007 Junior Subordinated Deferrable Debentures June 8, 2007 $ 100,000 July 30, 2037 3.000 % (b) 5.900 % (e) Quarterly Flagstone 2007 Junior Subordinated Deferrable Debentures September 20, 2007 $ 25,000 September 15, 2037 3.100 % (b) 5.983 % (e) Quarterly 2010 Senior Notes due 2040 January 26, 2010 $ 250,000 January 26, 2040 8.875 % (d) 8.875 % (d) Semi-annually in arrears (a) Fixed interest rate for 5 years , floating interest rate of three-month LIBOR plus 3.550% thereafter, reset quarterly. (b) Floating interest rate of three-month LIBOR plus amount stated, reset quarterly. (c) Fixed interest rate for 5 years , floating interest rate of three-month LIBOR plus 2.950% thereafter, reset quarterly. (d) Fixed interest rate. (e) Fixed interest rate as a result of interest rate swap contracts entered into by the Company.
Summary of outstanding credit and other facilities	The Company’s outstanding credit facilities as at September 30, 2017 and December 31, 2016 were as follows: September 30, 2017 Commitment Outstanding (a) Drawn (b) Cash and investments pledged as collateral Credit facilities $85,000 syndicated unsecured letter of credit facility $ 85,000 $ — $ — $ — $300,000 syndicated secured letter of credit facility 300,000 89,449 — 108,265 $24,000 secured bi-lateral letter of credit facility 24,000 5,767 — 22,342 $25,000 IPC bi-lateral facility 25,000 7,755 — — $236,000 Flagstone bi-lateral facility 236,000 90,390 — 134,482 $65,000 unsecured revolving credit facility 65,000 65,000 65,000 — $100,000 unsecured revolving credit facility 100,000 100,000 100,000 — Total credit facilities $ 835,000 $ 358,361 $ 165,000 $ 265,089 (a) Indicates utilization of commitment amount, not drawn borrowings. (b) Represents drawn borrowings included in accounts payable and accrued expenses. December 31, 2016 Commitment Outstanding (a) Drawn (b) Cash and investments pledged as collateral Credit facilities $85,000 syndicated unsecured letter of credit facility $ 85,000 $ — $ — $ — $300,000 syndicated secured letter of credit facility 300,000 121,428 — 157,597 $24,000 secured bi-lateral letter of credit facility 24,000 4,553 — 48,097 $20,000 AlphaCat Re secured letter of credit facility (c) 20,000 20,000 — 20,032 $25,000 IPC bi-lateral facility 25,000 8,807 — — $236,000 Flagstone bi-lateral facility 236,000 156,375 — 216,458 Total credit facilities $ 690,000 $ 311,163 $ — $ 442,184 (a) Indicates utilization of commitment amount, not drawn borrowings. (b) Represents drawn borrowings. (c) The Company terminated its AlphaCat Re secured letter of credit facility on January 6, 2017.
Components of finance expenses	Finance expenses consist of interest on the junior subordinated deferrable debentures and senior notes, the amortization of debt offering costs, credit facility fees, bank charges, AlphaCat financing fees and other charges as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 2006 Junior Subordinated Deferrable Debentures $ 2,235 $ 2,135 $ 6,633 $ 6,557 2007 Junior Subordinated Deferrable Debentures 1,851 1,851 5,492 5,512 Flagstone 2006 Junior Subordinated Deferrable Debentures 2,272 2,271 6,741 6,760 Flagstone 2007 Junior Subordinated Deferrable Debentures 1,775 1,784 5,249 5,317 2010 Senior Notes due 2040 5,597 5,597 16,792 16,791 Credit facilities 575 463 1,196 1,359 Bank and other charges 183 276 465 489 AlphaCat fees (a) 35 144 107 1,105 Total finance expenses $ 14,523 $ 14,521 $ 42,675 $ 43,890 (a) Includes finance expenses incurred by AlphaCat Managers Ltd. in relation to fund raising for the AlphaCat sidecars, the AlphaCat ILS funds and AlphaCat direct.

Accumulated other comprehensi38

Accumulated other comprehensive loss (Tables)	9 Months Ended
	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of changes in accumulated other comprehensive loss	The changes in accumulated other comprehensive loss, by component for the three and nine months ended September 30, 2017 and 2016 was as follows: Three Months Ended September 30, 2017 Foreign currency translation adjustment Minimum pension liability Cash flow hedge Total Balance, net of tax, beginning of period $ (20,188 ) $ 1,102 $ (838 ) $ (19,924 ) Other comprehensive income, net of tax 1,481 — 13 1,494 Balance, net of tax, end of period $ (18,707 ) $ 1,102 $ (825 ) $ (18,430 ) Three Months Ended September 30, 2016 Foreign currency translation adjustment Minimum pension liability Cash flow hedge Total Balance, net of tax, beginning of period $ (17,149 ) $ 730 $ (1,763 ) $ (18,182 ) Other comprehensive loss, net of tax (1,370 ) (1,101 ) (439 ) (2,910 ) Balance, net of tax, end of period $ (18,519 ) $ (371 ) $ (2,202 ) $ (21,092 ) Nine Months Ended September 30, 2017 Foreign currency translation adjustment Minimum pension liability Cash flow hedge Total Balance, net of tax, beginning of period $ (22,274 ) $ (150 ) $ (792 ) $ (23,216 ) Other comprehensive income (loss), net of tax 3,567 1,252 (33 ) 4,786 Balance, net of tax, end of period $ (18,707 ) $ 1,102 $ (825 ) $ (18,430 ) Nine Months Ended September 30, 2016 Foreign currency translation adjustment Minimum pension liability Cash flow hedge Total Balance, net of tax, beginning of period $ (11,834 ) $ 334 $ (1,069 ) $ (12,569 ) Other comprehensive loss, net of tax (6,685 ) (705 ) (1,133 ) (8,523 ) Balance, net of tax, end of period $ (18,519 ) $ (371 ) $ (2,202 ) $ (21,092 )

Commitments and contingencies (

Commitments and contingencies (Tables)	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Unfunded investment commitments	As at September 30, 2017 and December 31, 2016 , the Company had total unfunded investment commitments related to the following: Unfunded investment commitments September 30, 2017 December 31, 2016 Fixed maturity investments (a) $ 21,959 $ 28,499 Other investments (b) 101,082 156,134 Investments in investment affiliates (c) 87,372 64,071 AlphaCat ILS Fund — 10,000 Total unfunded investment commitments $ 210,413 $ 258,704 (a) The Company has an outstanding commitment to participate in certain secured loan facilities through participation agreements with an established loan originator. (b) The Company’s total capital commitments related to other investments as at September 30, 2017 was $313,000 ( December 31, 2016 : $308,000 ). (c) Refer to Note 4 (c), “Investments in Investment Affiliates.”

Earnings per share (Tables)

Earnings per share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Computation of basic and diluted earnings per share	The following table sets forth the computation of basic earnings per common share and earnings per diluted common share for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Basic (loss) earnings per common share Net (loss) income (attributable) available to Validus common shareholders $ (250,446 ) $ 89,844 $ (54,790 ) $ 351,617 Weighted average number of common shares outstanding 78,994,335 80,134,394 79,132,856 81,635,496 Basic (loss) earnings per share (attributable) available to Validus common shareholders $ (3.17 ) $ 1.12 $ (0.69 ) $ 4.31 (Loss) earnings per diluted common share Net (loss) income (attributable) available to Validus common shareholders $ (250,446 ) $ 89,844 $ (54,790 ) $ 351,617 Weighted average number of common shares outstanding 78,994,335 80,134,394 79,132,856 81,635,496 Share equivalents: Stock options — 26,705 — 32,126 Unvested restricted shares — 1,083,457 — 1,271,002 Weighted average number of diluted common shares outstanding 78,994,335 81,244,556 79,132,856 82,938,624 (Loss) earnings per diluted share (attributable) available to Validus common shareholders $ (3.17 ) $ 1.11 $ (0.69 ) $ 4.24

Segment information (Tables)

Segment information (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Summary of results of operating segments and Corporate and Investments	The following tables summarize the results of our operating segments and “Corporate and Investments”: Three Months Ended September 30, Nine Months Ended September 30, Validus Re Segment Information 2017 2016 2017 2016 Underwriting revenues Gross premiums written $ 153,890 $ 94,741 $ 1,071,409 $ 1,072,219 Reinsurance premiums ceded (40,988 ) (15,967 ) (161,188 ) (111,658 ) Net premiums written 112,902 78,774 910,221 960,561 Change in unearned premiums 154,145 149,705 (184,155 ) (241,129 ) Net premiums earned 267,047 228,479 726,066 719,432 Other insurance related income (loss) 68 58 204 (107 ) Total underwriting revenues 267,115 228,537 726,270 719,325 Underwriting deductions Losses and loss expenses 347,484 98,425 538,323 313,432 Policy acquisition costs 45,422 42,837 133,836 127,660 General and administrative expenses 12,444 17,528 48,550 52,579 Share compensation expenses 2,606 2,695 7,746 8,371 Total underwriting deductions 407,956 161,485 728,455 502,042 Underwriting (loss) income $ (140,841 ) $ 67,052 $ (2,185 ) $ 217,283 Selected ratios Ratio of net to gross premiums written 73.4 % 83.1 % 85.0 % 89.6 % Losses and loss expense ratio 130.1 % 43.1 % 74.1 % 43.6 % Policy acquisition cost ratio 17.0 % 18.7 % 18.4 % 17.7 % General and administrative expense ratio (a) 5.7 % 8.9 % 7.8 % 8.5 % Expense ratio 22.7 % 27.6 % 26.2 % 26.2 % Combined ratio 152.8 % 70.7 % 100.3 % 69.8 % (a) The general and administrative expense ratio includes share compensation expenses. Three Months Ended September 30, Nine Months Ended September 30, Talbot Segment Information 2017 2016 2017 2016 Underwriting revenues Gross premiums written $ 192,883 $ 189,674 $ 702,535 $ 752,058 Reinsurance premiums ceded (36,462 ) (22,877 ) (154,263 ) (137,496 ) Net premiums written 156,421 166,797 548,272 614,562 Change in unearned premiums 23,191 32,258 18,279 (7,166 ) Net premiums earned 179,612 199,055 566,551 607,396 Other insurance related income 692 99 1,512 389 Total underwriting revenues 180,304 199,154 568,063 607,785 Underwriting deductions Losses and loss expenses 178,440 109,860 378,241 319,271 Policy acquisition costs 41,493 46,488 129,074 134,444 General and administrative expenses 23,069 32,333 97,094 109,929 Share compensation expenses 2,310 3,163 8,292 9,955 Total underwriting deductions 245,312 191,844 612,701 573,599 Underwriting (loss) income $ (65,008 ) $ 7,310 $ (44,638 ) $ 34,186 Selected ratios Ratio of net to gross premiums written 81.1 % 87.9 % 78.0 % 81.7 % Losses and loss expense ratio 99.3 % 55.2 % 66.8 % 52.6 % Policy acquisition cost ratio 23.1 % 23.4 % 22.8 % 22.1 % General and administrative expense ratio (a) 14.2 % 17.8 % 18.5 % 19.7 % Expense ratio 37.3 % 41.2 % 41.3 % 41.8 % Combined ratio 136.6 % 96.4 % 108.1 % 94.4 % (a) The general and administrative expense ratio includes share compensation expenses. Three Months Ended September 30, Nine Months Ended September 30, Western World Segment Information 2017 2016 2017 2016 Underwriting revenues Gross premiums written $ 156,517 $ 85,260 $ 459,628 $ 236,190 Reinsurance premiums ceded (43,207 ) (6,202 ) (72,005 ) (15,347 ) Net premiums written 113,310 79,058 387,623 220,843 Change in unearned premiums 61,603 (8,260 ) 15,256 (22,890 ) Net premiums earned 174,913 70,798 402,879 197,953 Other insurance related income 662 219 1,566 696 Total underwriting revenues 175,575 71,017 404,445 198,649 Underwriting deductions Losses and loss expenses 157,709 45,748 329,642 129,623 Policy acquisition costs 20,721 17,094 60,187 46,704 General and administrative expenses 21,553 10,171 50,623 33,704 Share compensation expenses 354 702 1,655 1,825 Total underwriting deductions 200,337 73,715 442,107 211,856 Underwriting (loss) $ (24,762 ) $ (2,698 ) $ (37,662 ) $ (13,207 ) Selected ratios Ratio of net to gross premiums written 72.4 % 92.7 % 84.3 % 93.5 % Losses and loss expense ratio 90.2 % 64.6 % 81.8 % 65.5 % Policy acquisition cost ratio 11.8 % 24.1 % 14.9 % 23.6 % General and administrative expense ratio (a) 12.5 % 15.4 % 13.0 % 17.9 % Expense ratio 24.3 % 39.5 % 27.9 % 41.5 % Combined ratio 114.5 % 104.1 % 109.7 % 107.0 % (a) The general and administrative expense ratio includes share compensation expenses. Three Months Ended September 30, Nine Months Ended September 30, AlphaCat Segment Information 2017 2016 2017 2016 Fee revenues Third party $ 5,095 $ 7,025 $ 15,288 $ 14,843 Related party 457 1,373 1,732 2,592 Total fee revenues 5,552 8,398 17,020 17,435 Expenses General and administrative expenses 2,929 3,324 10,322 7,557 Share compensation expenses 183 (107 ) 348 167 Finance expenses 32 31 107 914 Tax (benefit) expense (65 ) — 69 — Foreign exchange losses 7 5 7 17 Total expenses 3,086 3,253 10,853 8,655 Income before investments from AlphaCat Funds and Sidecars 2,466 5,145 6,167 8,780 Investment (loss) income from AlphaCat Funds and Sidecars (a) AlphaCat Sidecars 201 (72 ) 68 593 AlphaCat ILS Funds - Lower Risk (b) (7,553 ) 2,321 (4,063 ) 6,903 AlphaCat ILS Funds - Higher Risk (b) (21,816 ) 2,479 (16,849 ) 5,607 BetaCat ILS Funds (922 ) 1,303 (291 ) 2,979 PaCRe — — — (23 ) Validus’ share of investment (loss) income from AlphaCat Funds and Sidecars (30,090 ) 6,031 (21,135 ) 16,059 Validus’ share of AlphaCat segment (loss) income $ (27,624 ) $ 11,176 $ (14,968 ) $ 24,839 Supplemental information Gross premiums written AlphaCat Sidecars $ — $ (112 ) $ 66 $ (178 ) AlphaCat ILS Funds - Lower Risk (b) 10,979 2,049 117,519 112,241 AlphaCat ILS Funds - Higher Risk (b) 16,275 1,797 153,483 140,127 AlphaCat Direct (c) (41 ) 679 26,753 18,476 Total gross premiums written $ 27,213 $ 4,413 $ 297,821 $ 270,666 (a) The investment (loss) income from the AlphaCat funds and sidecars is based on equity accounting. (b) Lower risk AlphaCat ILS funds have a maximum permitted portfolio expected loss of less than 7%, whereas higher risk AlphaCat ILS funds have a maximum permitted portfolio expected loss of greater than 7%. Expected loss represents the average annual loss over the set of simulation scenarios divided by the total limit. (c) AlphaCat Direct includes direct investments from third party investors in AlphaCat Re. Three Months Ended September 30, Nine Months Ended September 30, Corporate and Investments 2017 2016 2017 2016 Managed investments Managed net investment income (a) $ 37,091 $ 41,071 $ 111,346 $ 105,843 Net realized gains on managed investments (a) 903 4,080 280 5,514 Change in net unrealized gains on managed investments (a) 941 4,652 31,232 81,782 Income (loss) from investment affiliates 1,011 453 15,665 (4,249 ) Total managed investment return 39,946 50,256 158,523 188,890 Corporate expenses General and administrative expenses 9,539 18,221 45,563 52,276 Share compensation expenses 3,990 4,048 12,039 12,147 Finance expenses (a) 14,449 14,317 42,462 42,637 Dividends on preferred shares 5,627 2,252 10,033 2,252 Tax (benefit) expense (a) (2,567 ) 1,830 (7,237 ) 1,418 Total Corporate expenses 31,038 40,668 102,860 110,730 Other items Foreign exchange (losses) (a) (1,495 ) (1,067 ) (7,715 ) 11,628 Other income (loss) 35 (1,529 ) 303 (773 ) Transaction expenses — — (4,427 ) — Total other items (1,460 ) (2,596 ) (11,839 ) 10,855 Total Corporate and Investments $ 7,448 $ 6,992 $ 43,824 $ 89,015 (a) These items exclude the components which are included in Validus’ share of AlphaCat and amounts which are consolidated from VIEs. The following tables reconcile the results of our operating segments along with our corporate and investments function to the Consolidated results of the Company for the periods indicated: Three Months Ended September 30, 2017 Validus Re Segment Talbot Segment Western World Segment AlphaCat Segment and Consolidated VIEs Corporate and Investments Eliminations Total Underwriting revenues Gross premiums written $ 153,890 $ 192,883 $ 156,517 $ 27,213 $ — $ (6,647 ) $ 523,856 Reinsurance premiums ceded (40,988 ) (36,462 ) (43,207 ) (2,850 ) — 6,647 (116,860 ) Net premiums written 112,902 156,421 113,310 24,363 — — 406,996 Change in unearned premiums 154,145 23,191 61,603 77,273 — — 316,212 Net premiums earned 267,047 179,612 174,913 101,636 — — 723,208 Other insurance related income 68 692 662 6,083 — (3,969 ) 3,536 Total underwriting revenues 267,115 180,304 175,575 107,719 — (3,969 ) 726,744 Underwriting deductions Losses and loss expenses 347,484 178,440 157,709 570,969 — — 1,254,602 Policy acquisition costs 45,422 41,493 20,721 8,314 — (360 ) 115,590 General and administrative expenses 12,444 23,069 21,553 7,687 9,539 (3,950 ) 70,342 Share compensation expenses 2,606 2,310 354 183 3,990 — 9,443 Total underwriting deductions 407,956 245,312 200,337 587,153 13,529 (4,310 ) 1,449,977 Underwriting (loss) $ (140,841 ) $ (65,008 ) $ (24,762 ) $ (479,434 ) $ (13,529 ) $ 341 $ (723,233 ) Net investment return (a) — — — 1,232 39,946 — 41,178 Other items (b) — — — 82 (18,969 ) — (18,887 ) Loss attributable to AlphaCat investors — — — 74,130 — — 74,130 Net loss attributable to noncontrolling interest — — — 376,366 — — 376,366 Segmental (loss) $ (140,841 ) $ (65,008 ) $ (24,762 ) $ (27,624 ) $ 7,448 $ 341 Net loss attributable to Validus common shareholders $ (250,446 ) (a) Net investment return includes net investment income, net realized and change in net unrealized gains (losses) on investments and income (loss) from investment affiliates. (b) Other items includes finance expenses, transaction expenses, dividends on preferred shares, tax benefit (expense), foreign exchange gains (losses), income (loss) from operating affiliate and other income (loss). Three Months Ended September 30, 2016 Validus Re Segment Talbot Segment Western World Segment AlphaCat Segment and Consolidated VIEs Corporate and Investments Eliminations Total Underwriting revenues Gross premiums written $ 94,741 $ 189,674 $ 85,260 $ 4,413 $ — $ (1,670 ) $ 372,418 Reinsurance premiums ceded (15,967 ) (22,877 ) (6,202 ) (1,630 ) — 1,670 (45,006 ) Net premiums written 78,774 166,797 79,058 2,783 — — 327,412 Change in unearned premiums 149,705 32,258 (8,260 ) 62,660 — — 236,363 Net premiums earned 228,479 199,055 70,798 65,443 — — 563,775 Other insurance related income 58 99 219 8,656 — (8,113 ) 919 Total underwriting revenues 228,537 199,154 71,017 74,099 — (8,113 ) 564,694 Underwriting deductions Losses and loss expenses 98,425 109,860 45,748 4,361 — — 258,394 Policy acquisition costs 42,837 46,488 17,094 7,075 — (60 ) 113,434 General and administrative expenses 17,528 32,333 10,171 12,255 18,221 (8,065 ) 82,443 Share compensation expenses 2,695 3,163 702 (107 ) 4,048 — 10,501 Total underwriting deductions 161,485 191,844 73,715 23,584 22,269 (8,125 ) 464,772 Underwriting income (loss) $ 67,052 $ 7,310 $ (2,698 ) $ 50,515 $ (22,269 ) $ 12 $ 99,922 Net investment return (a) — — — 3,567 50,256 — 53,823 Other items (b) — — — 97 (20,995 ) — (20,898 ) (Income) attributable to AlphaCat investors — — — (5,564 ) — — (5,564 ) Net (income) attributable to noncontrolling interest — — — (37,439 ) — — (37,439 ) Segmental income (loss) $ 67,052 $ 7,310 $ (2,698 ) $ 11,176 $ 6,992 $ 12 Net income available to Validus common shareholders $ 89,844 (a) Net investment return includes net investment income, net realized and change in net unrealized gains (losses) on investments and income (loss) from investment affiliates. (b) Other items includes finance expenses, transaction expenses, dividends on preferred shares, tax benefit (expense), foreign exchange gains (losses), income (loss) from operating affiliate and other income (loss). Nine Months Ended September 30, 2017 Validus Re Segment Talbot Segment Western World Segment AlphaCat Segment and Consolidated VIEs Corporate and Investments Eliminations Total Underwriting revenues Gross premiums written $ 1,071,409 $ 702,535 $ 459,628 $ 297,821 $ — $ (23,778 ) $ 2,507,615 Reinsurance premiums ceded (161,188 ) (154,263 ) (72,005 ) (9,510 ) — 23,778 (373,188 ) Net premiums written 910,221 548,272 387,623 288,311 — — 2,134,427 Change in unearned premiums (184,155 ) 18,279 15,256 (54,196 ) — — (204,816 ) Net premiums earned 726,066 566,551 402,879 234,115 — — 1,929,611 Other insurance related income 204 1,512 1,566 17,118 — (14,463 ) 5,937 Total underwriting revenues 726,270 568,063 404,445 251,233 — (14,463 ) 1,935,548 Underwriting deductions Losses and loss expenses 538,323 378,241 329,642 574,130 — — 1,820,336 Policy acquisition costs 133,836 129,074 60,187 22,380 — (991 ) 344,486 General and administrative expenses 48,550 97,094 50,623 27,096 45,563 (14,311 ) 254,615 Share compensation expenses 7,746 8,292 1,655 348 12,039 — 30,080 Total underwriting deductions 728,455 612,701 442,107 623,954 57,602 (15,302 ) 2,449,517 Underwriting (loss) $ (2,185 ) $ (44,638 ) $ (37,662 ) $ (372,721 ) $ (57,602 ) $ 839 $ (513,969 ) Net investment return (a) — — — 12,543 158,523 — 171,066 Other items (b) — — — 269 (57,097 ) — (56,828 ) Loss attributable to AlphaCat investors — — — 54,797 — — 54,797 Net loss attributable to noncontrolling interest — — — 290,144 — — 290,144 Segmental (loss) $ (2,185 ) $ (44,638 ) $ (37,662 ) $ (14,968 ) $ 43,824 $ 839 Net loss attributable to Validus common shareholders $ (54,790 ) (a) Net investment return includes net investment income, net realized and change in net unrealized gains (losses) on investments and income (loss) from investment affiliates. (b) Other items includes finance expenses, transaction expenses, dividends on preferred shares, tax benefit (expense), foreign exchange gains (losses), income (loss) from operating affiliate and other income (loss). Nine Months Ended September 30, 2016 Validus Re Segment Talbot Segment Western World Segment AlphaCat Segment and Consolidated VIEs Corporate and Investments Eliminations Total Underwriting revenues Gross premiums written $ 1,072,219 $ 752,058 $ 236,190 $ 270,666 $ — $ (21,882 ) $ 2,309,251 Reinsurance premiums ceded (111,658 ) (137,496 ) (15,347 ) (6,451 ) — 21,882 (249,070 ) Net premiums written 960,561 614,562 220,843 264,215 — — 2,060,181 Change in unearned premiums (241,129 ) (7,166 ) (22,890 ) (80,230 ) — — (351,415 ) Net premiums earned 719,432 607,396 197,953 183,985 — — 1,708,766 Other insurance related (loss) income (107 ) 389 696 17,722 — (16,300 ) 2,400 Total underwriting revenues 719,325 607,785 198,649 201,707 — (16,300 ) 1,711,166 Underwriting deductions Losses and loss expenses 313,432 319,271 129,623 27,645 — — 789,971 Policy acquisition costs 127,660 134,444 46,704 19,762 — 23 328,593 General and administrative expenses 52,579 109,929 33,704 26,272 52,276 (16,421 ) 258,339 Share compensation expenses 8,371 9,955 1,825 167 12,147 — 32,465 Total underwriting deductions 502,042 573,599 211,856 73,846 64,423 (16,398 ) 1,409,368 Underwriting income (loss) $ 217,283 $ 34,186 $ (13,207 ) $ 127,861 $ (64,423 ) $ 98 $ 301,798 Net investment return (a) — — — 10,558 188,890 (597 ) 198,851 Other items (b) — — — (1,139 ) (35,452 ) — (36,591 ) (Income) attributable to AlphaCat investors — — — (16,278 ) — — (16,278 ) Net (income) attributable to noncontrolling interest — — — (96,163 ) — — (96,163 ) Segmental income (loss) $ 217,283 $ 34,186 $ (13,207 ) $ 24,839 $ 89,015 $ (499 ) Net income available to Validus common shareholders $ 351,617 (a) Net investment return includes net investment income, net realized and change in net unrealized gains (losses) on investments and income (loss) from investment affiliates. (b) Other items includes finance expenses, transaction expenses, dividends on preferred shares, tax benefit (expense), foreign exchange gains (losses), income (loss) from operating affiliate and other income (loss).
Gross premiums written allocated to the territory of coverage exposure	The following tables set forth the gross premiums written by operating segment allocated to the territory of coverage exposure for the periods indicated: Gross Premiums Written Three Months Ended September 30, 2017 Validus Re Talbot Western World AlphaCat Eliminations Total % United States $ 59,838 $ 24,584 $ 156,517 $ 18,440 $ (6,300 ) $ 253,079 48.3 % Worldwide excluding United States (a) 7,198 43,136 — 712 76 51,122 9.8 % Australia and New Zealand (450 ) 3,696 — — 9 3,255 0.6 % Europe 4,744 5,372 — 149 62 10,327 2.0 % Latin America and Caribbean 19,430 20,726 — — (454 ) 39,702 7.6 % Japan 436 1,165 — — — 1,601 0.3 % Canada 24 1,820 — 458 (6 ) 2,296 0.4 % Rest of the world (b) 1,447 21,478 — — 57 22,982 4.4 % Sub-total, non United States 32,829 97,393 — 1,319 (256 ) 131,285 25.1 % Worldwide including United States (a) 33,724 16,293 — 4,993 (91 ) 54,919 10.5 % Other locations non-specific (c) 27,499 54,613 — 2,461 — 84,573 16.1 % Total $ 153,890 $ 192,883 $ 156,517 $ 27,213 $ (6,647 ) $ 523,856 100.0 % Gross Premiums Written Three Months Ended September 30, 2016 Validus Re Talbot Western World AlphaCat Eliminations Total % United States $ 31,345 $ 19,937 $ 85,260 $ 1,837 $ (76 ) $ 138,303 37.1 % Worldwide excluding United States (a) 4,145 40,058 — (288 ) (39 ) 43,876 11.7 % Australia and New Zealand 57 3,238 — — 6 3,301 0.9 % Europe 4,536 4,957 — — 40 9,533 2.6 % Latin America and Caribbean 17,036 25,173 — — (793 ) 41,416 11.1 % Japan (33 ) 997 — — 7 971 0.3 % Canada 149 2,015 — — (42 ) 2,122 0.6 % Rest of the world (b) 2,360 19,166 — — 66 21,592 5.8 % Sub-total, non United States 28,250 95,604 — (288 ) (755 ) 122,811 33.0 % Worldwide including United States (a) 22,399 12,771 — 2,872 (838 ) 37,204 10.0 % Other locations non-specific (c) 12,747 61,362 — (8 ) (1 ) 74,100 19.9 % Total $ 94,741 $ 189,674 $ 85,260 $ 4,413 $ (1,670 ) $ 372,418 100.0 % Gross Premiums Written Nine Months Ended September 30, 2017 Validus Re Talbot Western World AlphaCat Eliminations Total % United States $ 374,018 $ 88,139 $ 459,628 $ 116,691 $ (10,623 ) $ 1,027,853 41.0 % Worldwide excluding United States (a) 45,803 110,094 — 8,617 (463 ) 164,051 6.6 % Australia and New Zealand 3,745 8,726 — 2,003 (101 ) 14,373 0.6 % Europe 35,108 22,944 — 600 (368 ) 58,284 2.2 % Latin America and Caribbean 40,646 69,703 — 46 (4,737 ) 105,658 4.2 % Japan 40,902 6,371 — 3,855 (36 ) 51,092 2.0 % Canada 4,894 4,068 — 588 (55 ) 9,495 0.4 % Rest of the world (b) 20,229 67,918 — — (1,520 ) 86,627 3.5 % Sub-total, non United States 191,327 289,824 — 15,709 (7,280 ) 489,580 19.5 % Worldwide including United States (a) 189,669 74,385 — 158,239 (5,875 ) 416,418 16.6 % Other locations non-specific (c) 316,395 250,187 — 7,182 — 573,764 22.9 % Total $ 1,071,409 $ 702,535 $ 459,628 $ 297,821 $ (23,778 ) $ 2,507,615 100.0 % Gross Premiums Written Nine Months Ended September 30, 2016 Validus Re Talbot Western World AlphaCat Eliminations Total % United States $ 455,826 $ 85,182 $ 236,190 $ 64,566 $ (1,631 ) $ 840,133 36.4 % Worldwide excluding United States (a) 51,384 105,590 — 22,219 (650 ) 178,543 7.8 % Australia and New Zealand 6,906 7,613 — 4,949 (107 ) 19,361 0.8 % Europe 30,270 25,673 — 3,306 (668 ) 58,581 2.5 % Latin America and Caribbean 36,610 76,577 — — (6,330 ) 106,857 4.6 % Japan 39,892 5,579 — 3,221 (24 ) 48,668 2.1 % Canada 3,646 5,577 — 223 (129 ) 9,317 0.4 % Rest of the world (b) 22,307 76,456 — — (2,276 ) 96,487 4.2 % Sub-total, non United States 191,015 303,065 — 33,918 (10,184 ) 517,814 22.4 % Worldwide including United States (a) 169,737 75,423 — 170,639 (10,052 ) 405,747 17.6 % Other locations non-specific (c) 255,641 288,388 — 1,543 (15 ) 545,557 23.6 % Total $ 1,072,219 $ 752,058 $ 236,190 $ 270,666 $ (21,882 ) $ 2,309,251 100.1 % (a) Represents risks in two or more geographic zones. (b) Represents risks in one geographic zone. (c) The Other locations non-specific category refers to business for which an analysis of exposure by geographic zone is not applicable since these exposures can span multiple geographic areas and, in some instances, are not fixed locations.

Business combination - Fair val

Business combination - Fair value of net assets acquired (Details) $ in Thousands	May 01, 2017USD ($)StatesAgent	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Transaction expenses		$ 0	$ 0	$ 4,427	$ 0
Net loss reserves		42,575		42,575
Goodwill		$ 227,701		$ 227,701		$ 196,758
Crop Risk Services
Business Acquisition [Line Items]
Number of agents | Agent	1,170
Number of states | States	36
Total purchase price	$ 185,576
Cash and cash equivalents	1,653
Premiums receivable	564,453
Prepaid reinsurance premiums	227,157
Other assets	157,146
Assets acquired	950,409
Reinsurance balances payable	294,201
Unearned premiums	406,649
Net loss reserves	42,575
Other liabilities	122,715
Liabilities acquired	866,140
Excess purchase price	101,307
Total intangible assets	63,921
Goodwill	30,943
Deferred tax arising on Goodwill	$ 6,443
Crop Risk Services | Intangible asset - Distribution channels
Business Acquisition [Line Items]
Estimated useful life	10 years
Total intangible assets	$ 52,898
Crop Risk Services | Intangible asset - Brand name
Business Acquisition [Line Items]
Estimated useful life	10 years
Total intangible assets	$ 9,568
Crop Risk Services | Intangible asset - Technology
Business Acquisition [Line Items]
Estimated useful life	2 years
Total intangible assets	$ 1,455

Business combination - Reconcil

Business combination - Reconciliation of carrying amount of goodwill and intangible assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Goodwill And Other Intangible Assets [Line Items]
Goodwill, beginning of period	$ 196,758
Additions	30,943
Goodwill, end of period	227,701
Finite lived intangible assets, beginning of period	11,424
Indefinite lived intangible assets, beginning of period	104,168
Intangible assets, beginning of period	115,592
Additions, finite lived	63,921
Amortization	(6,115)	$ (4,248)
Finite lived intangible assets, end of period	69,230
Indefinite lived intangible assets, end of period	104,168
Intangible assets, end of period	173,398
Talbot
Goodwill And Other Intangible Assets [Line Items]
Goodwill, beginning of period	20,393
Additions	0
Goodwill, end of period	20,393
Intangible assets, beginning of period	93,924
Additions, finite lived	0
Amortization	(2,081)
Intangible assets, end of period	91,843
Western World
Goodwill And Other Intangible Assets [Line Items]
Goodwill, beginning of period	176,365
Additions	30,943
Goodwill, end of period	207,308
Intangible assets, beginning of period	21,668
Additions, finite lived	63,921
Amortization	(4,034)
Intangible assets, end of period	$ 81,555

Business combination - Suppleme

Business combination - Supplemental pro forma information (Details) - Crop Risk Services - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Business Acquisition [Line Items]
Net premiums written	$ 32,852	$ 39,840
Net premiums earned	98,757	148,801
Total underwriting deductions	84,826	129,606
Underwriting income, before general and administrative expenses	$ 13,931	$ 19,195

Investments (Amortized cost or

Investments (Amortized cost or cost and fair value of investments) (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		$ 5,421,546	$ 5,584,599
Short-term investments, at amortized cost or cost		2,992,939	2,796,358
Other investments, at amortized cost or cost		439,991	380,130
Investments in investment affiliates, at cost		60,228	84,840
Total investments		8,914,704	8,845,927
Fixed maturities, at fair value		5,419,966	5,543,030
Short-term investments, at fair value		2,993,246	2,796,170
Other investments, at fair value		471,300	405,712
Investments in investment affiliates, at fair value		92,079	100,431
Total investments		8,976,591	8,845,343
Managed investments
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		5,117,757	5,427,113
Short-term investments, at amortized cost or cost		258,339	228,574
Other investments, at amortized cost or cost		439,991	380,130
Investments in investment affiliates, at cost	[1]	60,228	84,840
Total investments		5,876,315	6,120,657
Fixed maturities, at fair value		5,120,482	5,384,699
Short-term investments, at fair value		258,646	228,386
Other investments, at fair value		471,300	405,712
Investments in investment affiliates, at fair value	[1]	92,079	100,431
Total investments		5,942,507	6,119,228
Managed investments | U.S. government and government agency
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		598,607	809,392
Fixed maturities, at fair value		595,694	804,126
Managed investments | Non-U.S. government and government agency
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		288,296	245,651
Fixed maturities, at fair value		290,538	240,791
Managed investments | U.S. states, municipalities and political subdivisions
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		205,880	271,742
Fixed maturities, at fair value		206,667	271,830
Managed investments | Agency residential mortgage-backed securities
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		830,542	684,490
Fixed maturities, at fair value		828,400	679,595
Managed investments | Non-agency residential mortgage-backed securities
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		38,806	15,858
Fixed maturities, at fair value		38,993	15,477
Managed investments | U.S. corporate
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		1,457,073	1,540,036
Fixed maturities, at fair value		1,466,739	1,534,508
Managed investments | Non-U.S. corporate
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		390,519	418,520
Fixed maturities, at fair value		392,242	410,227
Managed investments | Bank loans
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		471,855	579,121
Fixed maturities, at fair value		464,464	570,399
Managed investments | Asset-backed securities
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		520,594	528,563
Fixed maturities, at fair value		522,524	526,814
Managed investments | Commercial mortgage-backed securities
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		315,585	333,740
Fixed maturities, at fair value		314,221	330,932
Managed investments | Fund of hedge funds
Amortized cost (or cost) and estimated fair value of investments
Other investments, at amortized cost or cost		0	1,457
Other investments, at fair value		0	955
Managed investments | Hedge funds
Amortized cost (or cost) and estimated fair value of investments
Other investments, at amortized cost or cost		11,292	11,292
Other investments, at fair value		19,233	17,381
Managed investments | Private equity investments
Amortized cost (or cost) and estimated fair value of investments
Other investments, at amortized cost or cost		88,299	66,383
Other investments, at fair value		107,230	82,627
Managed investments | Fixed income investment funds
Amortized cost (or cost) and estimated fair value of investments
Other investments, at amortized cost or cost		282,707	247,967
Other investments, at fair value		285,034	249,275
Managed investments | Overseas deposits
Amortized cost (or cost) and estimated fair value of investments
Other investments, at amortized cost or cost		55,775	50,106
Other investments, at fair value		55,775	50,106
Managed investments | Mutual funds
Amortized cost (or cost) and estimated fair value of investments
Other investments, at amortized cost or cost		1,918	2,925
Other investments, at fair value		4,028	5,368
Non-managed investments
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		303,789	157,486
Short-term investments, at amortized cost or cost		2,734,600	2,567,784
Total investments		3,038,389	2,725,270
Fixed maturities, at fair value		299,484	158,331
Short-term investments, at fair value		2,734,600	2,567,784
Total investments		3,034,084	2,726,115
Non-managed investments | Catastrophe bonds
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		303,789	157,486
Fixed maturities, at fair value		$ 299,484	$ 158,331
[1]	The Company’s investments in investment affiliates have been treated as equity method investments with the corresponding gains and losses recorded inincome as “Income (loss) from investment affiliates.”

Investments (Fixed maturities b

Investments (Fixed maturities by investment rating) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fixed Maturities
Fair value	$ 5,419,966	$ 5,543,030
Percentage of total	100.00%	100.00%
Managed investments
Fixed Maturities
Fair value	$ 5,120,482	$ 5,384,699
Percentage of total	94.50%	97.10%
Managed investments | Total investment grade fixed maturities
Fixed Maturities
Fair value	$ 4,600,675	$ 4,766,696
Percentage of total	84.90%	86.00%
Managed investments | Total investment grade fixed maturities | AAA
Fixed Maturities
Fair value	$ 2,349,803	$ 2,405,597
Percentage of total	43.30%	43.40%
Managed investments | Total investment grade fixed maturities | AA
Fixed Maturities
Fair value	$ 437,215	$ 538,289
Percentage of total	8.10%	9.70%
Managed investments | Total investment grade fixed maturities | A rating
Fixed Maturities
Fair value	$ 1,060,849	$ 1,081,949
Percentage of total	19.60%	19.50%
Managed investments | Total investment grade fixed maturities | BBB
Fixed Maturities
Fair value	$ 752,808	$ 740,861
Percentage of total	13.90%	13.40%
Managed investments | Total non-investment grade fixed maturities
Fixed Maturities
Fair value	$ 519,807	$ 618,003
Percentage of total	9.60%	11.10%
Managed investments | Total non-investment grade fixed maturities | BB
Fixed Maturities
Fair value	$ 177,667	$ 213,568
Percentage of total	3.20%	3.90%
Managed investments | Total non-investment grade fixed maturities | B
Fixed Maturities
Fair value	$ 156,590	$ 177,737
Percentage of total	2.90%	3.20%
Managed investments | Total non-investment grade fixed maturities | CCC
Fixed Maturities
Fair value	$ 5,286	$ 13,371
Percentage of total	0.10%	0.20%
Managed investments | Total non-investment grade fixed maturities | NR
Fixed Maturities
Fair value	$ 180,264	$ 213,327
Percentage of total	3.40%	3.80%
Non-managed investments
Fixed Maturities
Fair value	$ 299,484	$ 158,331
Percentage of total	5.50%	2.90%
Non-managed investments | Total investment grade fixed maturities
Fixed Maturities
Fair value	$ 1,650	$ 0
Percentage of total	0.00%	0.00%
Non-managed investments | Total investment grade fixed maturities | BBB
Fixed Maturities
Fair value	$ 1,650	$ 0
Percentage of total	0.00%	0.00%
Non-managed investments | Total non-investment grade fixed maturities
Fixed Maturities
Fair value	$ 297,834	$ 158,331
Percentage of total	5.50%	2.90%
Non-managed investments | Total non-investment grade fixed maturities | BB
Fixed Maturities
Fair value	$ 28,031	$ 29,731
Percentage of total	0.50%	0.60%
Non-managed investments | Total non-investment grade fixed maturities | B
Fixed Maturities
Fair value	$ 2,755	$ 4,524
Percentage of total	0.10%	0.10%
Non-managed investments | Total non-investment grade fixed maturities | NR
Fixed Maturities
Fair value	$ 267,048	$ 124,076
Percentage of total	4.90%	2.20%

Investments (Maturity profile o

Investments (Maturity profile of fixed maturity investments) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Maturity profile
Amortized cost	$ 5,421,546	$ 5,584,599
Fair value	5,419,966	5,543,030
Managed investments
Maturity profile
Amortized cost	5,117,757	5,427,113
Fair value	5,120,482	5,384,699
Managed investments | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost	3,412,230	3,864,462
Fair value	3,416,344	3,831,881
Managed investments | Due in one year or less | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost	279,069	350,733
Fair value	278,118	346,161
Managed investments | Due after one year through five years | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost	2,418,737	2,954,856
Fair value	2,416,963	2,933,146
Managed investments | Due after five years through ten years | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost	534,922	430,365
Fair value	535,538	426,647
Managed investments | Due after ten years | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost	179,502	128,508
Fair value	185,725	125,927
Managed investments | Asset backed and mortgaged backed securities
Maturity profile
Amortized cost	1,705,527	1,562,651
Fair value	1,704,138	1,552,818
Non-managed investments
Maturity profile
Amortized cost	303,789	157,486
Fair value	299,484	158,331
Non-managed investments | Due in one year or less
Maturity profile
Amortized cost	88,949	43,664
Fair value	88,202	45,418
Non-managed investments | Due after one year through five years
Maturity profile
Amortized cost	209,340	112,572
Fair value	206,117	111,656
Non-managed investments | Due after five years through ten years
Maturity profile
Amortized cost	5,500	1,250
Fair value	$ 5,165	$ 1,257

Investments (Other investments)

Investments (Other investments) (Details) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Investment [Line Items]
Other investments, at fair value		$ 471,300	$ 405,712
Managed investments
Investment [Line Items]
Other investments, at fair value		471,300	405,712
Managed investments | Fund of hedge funds
Investment [Line Items]
Other investments, at fair value		0	955
Managed investments | Hedge funds
Investment [Line Items]
Other investments, at fair value		19,233	17,381
Managed investments | Private equity investments
Investment [Line Items]
Other investments, at fair value		107,230	82,627
Managed investments | Fixed income investment funds
Investment [Line Items]
Other investments, at fair value		285,034	249,275
Managed investments | Overseas deposits
Investment [Line Items]
Other investments, at fair value		55,775	50,106
Managed investments | Mutual funds
Investment [Line Items]
Other investments, at fair value		4,028	5,368
Recurring | Managed investments
Investment [Line Items]
Other investments, at fair value		471,300	405,712
Recurring | Managed investments | Externally Rated or Consist of Externally Rated Securities
Investment [Line Items]
Other investments, at fair value		274,651
Recurring | Managed investments | Not Externally Rated
Investment [Line Items]
Other investments, at fair value		196,649
Recurring | Managed investments | Fund of hedge funds
Investment [Line Items]
Other investments, at fair value			955
Recurring | Managed investments | Hedge funds
Investment [Line Items]
Other investments, at fair value		19,233	17,381
Recurring | Managed investments | Private equity investments
Investment [Line Items]
Other investments, at fair value		107,230	82,627
Recurring | Managed investments | Fixed income investment funds
Investment [Line Items]
Other investments, at fair value		285,034	249,275
Recurring | Managed investments | Overseas deposits
Investment [Line Items]
Other investments, at fair value		55,775	50,106
Recurring | Managed investments | Mutual funds
Investment [Line Items]
Other investments, at fair value		4,028	5,368
Recurring | Managed investments | Subject to redemption restriction
Investment [Line Items]
Other investments, at fair value		432,237	369,402
Recurring | Managed investments | Subject to redemption restriction | Fund of hedge funds
Investment [Line Items]
Other investments, at fair value			955
Recurring | Managed investments | Subject to redemption restriction | Hedge funds
Investment [Line Items]
Other investments, at fair value		19,233	17,381
Recurring | Managed investments | Subject to redemption restriction | Private equity investments
Investment [Line Items]
Other investments, at fair value		107,230	82,627
Recurring | Managed investments | Subject to redemption restriction | Fixed income investment funds
Investment [Line Items]
Other investments, at fair value		249,999	218,333
Recurring | Managed investments | Subject to redemption restriction | Overseas deposits
Investment [Line Items]
Other investments, at fair value		55,775	50,106
Recurring | Managed investments | Subject to redemption restriction | Mutual funds
Investment [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Not subject to redemption restriction
Investment [Line Items]
Other investments, at fair value		39,063	36,310
Recurring | Managed investments | Not subject to redemption restriction | Fund of hedge funds
Investment [Line Items]
Other investments, at fair value			0
Recurring | Managed investments | Not subject to redemption restriction | Hedge funds
Investment [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Not subject to redemption restriction | Private equity investments
Investment [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Not subject to redemption restriction | Fixed income investment funds
Investment [Line Items]
Other investments, at fair value		$ 35,035	$ 30,942
Redemption frequency			Daily
Redemption notice period	[1]		2 days
Recurring | Managed investments | Not subject to redemption restriction | Fixed income investment funds | Minimum
Investment [Line Items]
Redemption frequency		P1D
Redemption notice period	[1]	1 day
Recurring | Managed investments | Not subject to redemption restriction | Fixed income investment funds | Maximum
Investment [Line Items]
Redemption frequency		P2D
Redemption notice period	[1]	2 days
Recurring | Managed investments | Not subject to redemption restriction | Overseas deposits
Investment [Line Items]
Other investments, at fair value		$ 0	$ 0
Recurring | Managed investments | Not subject to redemption restriction | Mutual funds
Investment [Line Items]
Other investments, at fair value		$ 4,028	$ 5,368
Redemption frequency		Daily	Daily
Redemption notice period	[1]	1 day	1 day
[1]	The redemption frequency and notice periods only apply to investments without redemption restrictions.

Investments (Investment affilia

Investments (Investment affiliate rollforward) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Schedule of Equity Method Investments [Line Items]
Investments in affiliates, beginning of period			$ 100,431
Income (loss) from investment affiliates	$ 1,011	$ 453	15,665	$ (4,249)
Investments in affiliates, end of period	92,079		92,079
Investment affiliate
Schedule of Equity Method Investments [Line Items]
Investments in affiliates, beginning of period	103,377	99,278	100,431	87,673
Net capital (distributions) contributions	(12,309)	0	(24,017)	16,307
Income (loss) from investment affiliates	1,011	453	15,665	(4,249)
Investments in affiliates, end of period	$ 92,079	$ 99,731	$ 92,079	$ 99,731

Investments (Investment affil50

Investments (Investment affiliate details) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Jun. 30, 2017	Mar. 20, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Investments in investment affiliates, at cost	$ 60,228			$ 84,840
Investments in affiliates	92,079			100,431
Aquiline Financial Services Fund II LP
Schedule of Equity Method Investments [Line Items]
Remaining capital commitment	3,229			2,040
Aquiline Financial Services Fund III LP
Schedule of Equity Method Investments [Line Items]
Remaining capital commitment	66,285			62,031
Aquiline Tech
Schedule of Equity Method Investments [Line Items]
Remaining capital commitment	17,858		$ 20,000
Investment affiliate
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	92,079	$ 103,377		100,431	$ 99,731	$ 99,278	$ 87,673
Investment affiliate | Aquiline Financial Services Fund II LP
Schedule of Equity Method Investments [Line Items]
Investments in investment affiliates, at cost	$ 33,349			$ 46,871
Voting ownership %	0.00%			0.00%
Equity ownership %	8.10%			8.10%
Investments in affiliates	$ 50,695			$ 61,999
Investment affiliate | Aquiline Financial Services Fund III LP
Schedule of Equity Method Investments [Line Items]
Investments in investment affiliates, at cost	$ 24,737			$ 37,969
Voting ownership %	0.00%			0.00%
Equity ownership %	9.00%			9.00%
Investments in affiliates	$ 39,530			$ 38,432
Investment affiliate | Aquiline Tech
Schedule of Equity Method Investments [Line Items]
Investments in investment affiliates, at cost	$ 2,142
Voting ownership %	0.00%
Equity ownership %	10.60%
Investments in affiliates	$ 1,854

Investments (Components of net

Investments (Components of net investment income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net investment income
Net investment income	$ 44,458	$ 43,514	$ 128,913	$ 112,232
Managed investments
Net investment income
Total gross investment income	39,447	43,253	118,117	112,051
Investment expenses	(2,356)	(2,182)	(6,771)	(6,208)
Net investment income	37,091	41,071	111,346	105,843
Managed investments | Fixed maturities and short term investments
Net investment income
Total gross investment income	30,823	30,572	93,706	89,210
Managed investments | Other investments
Net investment income
Total gross investment income	7,391	11,768	21,832	20,666
Managed investments | Restricted cash, cash and cash equivalents
Net investment income
Total gross investment income	1,230	891	2,556	2,136
Managed investments | Securities lending income
Net investment income
Total gross investment income	3	22	23	39
Non-managed investments
Net investment income
Net investment income	7,367	2,443	17,567	6,389
Non-managed investments | Fixed maturities and short term investments
Net investment income
Total gross investment income	3,941	1,970	11,501	5,242
Non-managed investments | Restricted cash, cash and cash equivalents
Net investment income
Total gross investment income	$ 3,426	$ 473	$ 6,066	$ 1,147

Investments (Realized and unrea

Investments (Realized and unrealized gains) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Fixed Maturities Short Term And Other Investments And Cash Equivalents [Abstract]
Net realized gains on investments	$ 906	$ 4,397	$ 2,016	$ 6,537
Change in net unrealized (losses) gains on investments	(5,197)	5,459	24,472	84,331
Total net realized and change in net unrealized gains (losses) on investments	(4,291)	9,856	26,488	90,868
Managed investments
Fixed Maturities Short Term And Other Investments And Cash Equivalents [Abstract]
Gross realized gains	5,170	4,544	13,035	11,067
Gross realized losses	(4,267)	(464)	(12,755)	(5,553)
Net realized gains on investments	903	4,080	280	5,514
Change in net unrealized (losses) gains on investments	941	4,652	31,232	81,782
Total net realized and change in net unrealized gains (losses) on investments	1,844	8,732	31,512	87,296
Non-managed investments
Fixed Maturities Short Term And Other Investments And Cash Equivalents [Abstract]
Gross realized gains	3	317	1,736	1,032
Gross realized losses	0	0	0	(9)
Net realized gains on investments	3	317	1,736	1,023
Change in net unrealized (losses) gains on investments	(6,138)	807	(6,760)	2,549
Total net realized and change in net unrealized gains (losses) on investments	$ (6,135)	$ 1,124	$ (5,024)	$ 3,572

Investments (Narrative) (Detail

Investments (Narrative) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)funds	Dec. 31, 2016USD ($)
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other investments, at fair value	$ 471,300	$ 405,712
Cash, cash equivalents, restricted cash and investments pledged as collateral	5,433,107	5,173,966
Investments held in trust	5,368,025	5,068,092
Investments and cash pledged as collateral	$ 265,089	442,184
Minimum
Schedule of Trading Securities and Other Trading Assets [Line Items]
Remaining liquidation period	5 years
Maximum
Schedule of Trading Securities and Other Trading Assets [Line Items]
Remaining liquidation period	10 years
Managed investments
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other investments, at fair value	$ 471,300	405,712
Recurring | Managed investments
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other investments, at fair value	471,300	405,712
Recurring | Managed investments | Subject to redemption restriction
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other investments, at fair value	$ 432,237	369,402
Recurring | Managed investments | Subject to redemption restriction | Investment fund A
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other investments number of funds | funds	1
Other investments, at fair value	$ 195,903	$ 184,749
Redemption restriction period	2 years

Fair value measurements (Fair v

Fair value measurements (Fair value hierarchy) (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		$ 5,419,966	$ 5,543,030
Short-term investments, at fair value		2,993,246	2,796,170
Other investments, at fair value		471,300	405,712
Investments in affiliates		92,079	100,431
Total investments		8,976,591	8,845,343
Managed investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		5,120,482	5,384,699
Short-term investments, at fair value		258,646	228,386
Other investments, at fair value		471,300	405,712
Investments in affiliates	[1]	92,079	100,431
Total investments		5,942,507	6,119,228
Managed investments | U.S. government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		595,694	804,126
Managed investments | Non-US government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		290,538	240,791
Managed investments | U.S. states, municipalities and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		206,667	271,830
Managed investments | Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		828,400	679,595
Managed investments | Non-Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		38,993	15,477
Managed investments | U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		1,466,739	1,534,508
Managed investments | Non-U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		392,242	410,227
Managed investments | Bank loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		464,464	570,399
Managed investments | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		522,524	526,814
Managed investments | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		314,221	330,932
Managed investments | Fund of hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		0	955
Managed investments | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		19,233	17,381
Managed investments | Private equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		107,230	82,627
Managed investments | Fixed income investment funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		285,034	249,275
Managed investments | Overseas deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		55,775	50,106
Managed investments | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		4,028	5,368
Non-managed investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		299,484	158,331
Short-term investments, at fair value		2,734,600	2,567,784
Total investments		3,034,084	2,726,115
Non-managed investments | Catastrophe bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		299,484	158,331
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments		8,976,591	8,845,343
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments		2,986,178	2,777,435
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments		5,137,610	5,279,272
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments		345,483	330,970
Recurring | Managed investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		5,120,482	5,384,699
Short-term investments, at fair value		258,646	228,386
Other investments, at fair value		471,300	405,712
Total investments		5,942,507	6,119,228
Recurring | Managed investments | U.S. government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		595,694	804,126
Recurring | Managed investments | Non-US government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		290,538	240,791
Recurring | Managed investments | U.S. states, municipalities and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		206,667	271,830
Recurring | Managed investments | Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		828,400	679,595
Recurring | Managed investments | Non-Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		38,993	15,477
Recurring | Managed investments | U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		1,466,739	1,534,508
Recurring | Managed investments | Non-U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		392,242	410,227
Recurring | Managed investments | Bank loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		464,464	570,399
Recurring | Managed investments | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		522,524	526,814
Recurring | Managed investments | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		314,221	330,932
Recurring | Managed investments | Fund of hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value			955
Recurring | Managed investments | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		19,233	17,381
Recurring | Managed investments | Private equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		107,230	82,627
Recurring | Managed investments | Fixed income investment funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		285,034	249,275
Recurring | Managed investments | Overseas deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		55,775	50,106
Recurring | Managed investments | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		4,028	5,368
Recurring | Managed investments | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Short-term investments, at fair value		251,578	209,651
Other investments, at fair value		0	0
Total investments		251,578	209,651
Recurring | Managed investments | Level 1 | U.S. government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 1 | Non-US government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 1 | U.S. states, municipalities and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 1 | Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 1 | Non-Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 1 | U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 1 | Non-U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 1 | Bank loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 1 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 1 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 1 | Fund of hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value			0
Recurring | Managed investments | Level 1 | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Level 1 | Private equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Level 1 | Fixed income investment funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Level 1 | Overseas deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Level 1 | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		4,860,594	5,114,272
Short-term investments, at fair value		7,068	18,735
Other investments, at fair value		39,173	36,309
Total investments		4,906,835	5,169,316
Recurring | Managed investments | Level 2 | U.S. government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		595,694	804,126
Recurring | Managed investments | Level 2 | Non-US government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		290,538	240,791
Recurring | Managed investments | Level 2 | U.S. states, municipalities and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		206,667	271,830
Recurring | Managed investments | Level 2 | Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		828,400	679,595
Recurring | Managed investments | Level 2 | Non-Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		38,993	15,477
Recurring | Managed investments | Level 2 | U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		1,466,739	1,534,508
Recurring | Managed investments | Level 2 | Non-U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		392,242	410,227
Recurring | Managed investments | Level 2 | Bank loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		240,563	323,903
Recurring | Managed investments | Level 2 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		486,537	502,883
Recurring | Managed investments | Level 2 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		314,221	330,932
Recurring | Managed investments | Level 2 | Fund of hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value			0
Recurring | Managed investments | Level 2 | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Level 2 | Private equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Level 2 | Fixed income investment funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		35,145	30,941
Recurring | Managed investments | Level 2 | Overseas deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Level 2 | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		4,028	5,368
Recurring | Managed investments | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		259,888	270,427
Short-term investments, at fair value		0	0
Other investments, at fair value		16,886	12,168
Total investments		276,774	282,595
Recurring | Managed investments | Level 3 | U.S. government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 3 | Non-US government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 3 | U.S. states, municipalities and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 3 | Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 3 | Non-Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 3 | U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 3 | Non-U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 3 | Bank loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		223,901	246,496
Recurring | Managed investments | Level 3 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		35,987	23,931
Recurring | Managed investments | Level 3 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Managed investments | Level 3 | Fund of hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value			0
Recurring | Managed investments | Level 3 | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Level 3 | Private equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Level 3 | Fixed income investment funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		16,886	12,168
Recurring | Managed investments | Level 3 | Overseas deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		0	0
Recurring | Managed investments | Level 3 | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		0	0
Recurring | Non-managed investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments, at fair value		2,734,600	2,567,784
Total investments		3,034,084	2,726,115
Recurring | Non-managed investments | Catastrophe bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		299,484	158,331
Recurring | Non-managed investments | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments, at fair value		2,734,600	2,567,784
Total investments		2,734,600	2,567,784
Recurring | Non-managed investments | Level 1 | Catastrophe bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		0	0
Recurring | Non-managed investments | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments, at fair value		0	0
Total investments		230,775	109,956
Recurring | Non-managed investments | Level 2 | Catastrophe bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		230,775	109,956
Recurring | Non-managed investments | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments, at fair value		0	0
Total investments		68,709	48,375
Recurring | Non-managed investments | Level 3 | Catastrophe bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		68,709	48,375
Recurring | Fair value based on NAV practical expedient
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	[2]	415,241	357,235
Recurring | Fair value based on NAV practical expedient | Managed investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	[2]	0	0
Short-term investments, at fair value	[2]	0	0
Other investments, at fair value	[2]	415,241	357,235
Total investments	[2]	415,241	357,235
Recurring | Fair value based on NAV practical expedient | Managed investments | U.S. government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	[2]	0	0
Recurring | Fair value based on NAV practical expedient | Managed investments | Non-US government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	[2]	0	0
Recurring | Fair value based on NAV practical expedient | Managed investments | U.S. states, municipalities and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	[2]	0	0
Recurring | Fair value based on NAV practical expedient | Managed investments | Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	[2]	0	0
Recurring | Fair value based on NAV practical expedient | Managed investments | Non-Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	[2]	0	0
Recurring | Fair value based on NAV practical expedient | Managed investments | U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	[2]	0	0
Recurring | Fair value based on NAV practical expedient | Managed investments | Non-U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	[2]	0	0
Recurring | Fair value based on NAV practical expedient | Managed investments | Bank loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	[2]	0	0
Recurring | Fair value based on NAV practical expedient | Managed investments | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	[2]	0	0
Recurring | Fair value based on NAV practical expedient | Managed investments | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	[2]	0	0
Recurring | Fair value based on NAV practical expedient | Managed investments | Fund of hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	[2]		955
Recurring | Fair value based on NAV practical expedient | Managed investments | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	[2]	19,233	17,381
Recurring | Fair value based on NAV practical expedient | Managed investments | Private equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	[2]	107,230	82,627
Recurring | Fair value based on NAV practical expedient | Managed investments | Fixed income investment funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	[2]	233,003	206,166
Recurring | Fair value based on NAV practical expedient | Managed investments | Overseas deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	[2]	55,775	50,106
Recurring | Fair value based on NAV practical expedient | Managed investments | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	[2]	0	0
Recurring | Fair value based on NAV practical expedient | Non-managed investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments, at fair value	[2]	0	0
Total investments	[2]	0	0
Recurring | Fair value based on NAV practical expedient | Non-managed investments | Catastrophe bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	[2]	$ 0	$ 0
[1]	The Company’s investments in investment affiliates have been treated as equity method investments with the corresponding gains and losses recorded inincome as “Income (loss) from investment affiliates.”
[2]	In accordance with ASC Topic 820 “Fair Value Measurements,” investments measured at fair value using the net asset value (“NAV”) per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy.

Fair value measurements (Level

Fair value measurements (Level 3 rollforward) (Details) - Recurring - Level 3 - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reconciliation of beginning and ending balances for all investments measured at fair value on recurring basis
Level 3 investments - beginning of period	$ 344,518	$ 293,049	$ 330,970	$ 245,837
Purchases	31,312	32,769	151,821	119,412
Sales	(71)	(12,388)	(124)	(14,777)
Settlements	(30,310)		(140,509)	(34,158)
Net realized gains			3,350
Change in net unrealized (losses) gains	34	1,001	(25)	(1,883)
Level 3 investments - end of period	345,483	314,431	345,483	314,431
Bank loan portfolio
Reconciliation of beginning and ending balances for all investments measured at fair value on recurring basis
Level 3 investments - beginning of period	224,172	243,148	246,496	232,337
Purchases	31,312	21,256	71,245	72,244
Sales	0	(12,388)	0	(14,777)
Settlements	(29,796)		(91,799)	(34,033)
Net realized gains			0
Change in net unrealized (losses) gains	(1,787)	484	(2,041)	(3,271)
Level 3 investments - end of period	223,901	252,500	223,901	252,500
Catastrophe bonds
Reconciliation of beginning and ending balances for all investments measured at fair value on recurring basis
Level 3 investments - beginning of period	68,025	37,518	48,375	13,500
Purchases	0	0	66,091	23,272
Sales	0	0	0	0
Settlements	(1,000)		(49,996)	(125)
Net realized gains			3,350
Change in net unrealized (losses) gains	1,684	517	889	1,388
Level 3 investments - end of period	68,709	38,035	68,709	38,035
Fixed income investment funds
Reconciliation of beginning and ending balances for all investments measured at fair value on recurring basis
Level 3 investments - beginning of period	16,400		12,168
Purchases	0		3,432
Sales	0		0
Settlements	486		1,286
Net realized gains			0
Change in net unrealized (losses) gains	0		0
Level 3 investments - end of period	16,886		16,886
Asset-backed securities
Reconciliation of beginning and ending balances for all investments measured at fair value on recurring basis
Level 3 investments - beginning of period	35,921	12,383	23,931	0
Purchases	0	11,513	11,053	23,896
Sales	(71)	0	(124)	0
Settlements	0		0	0
Net realized gains			0
Change in net unrealized (losses) gains	137	0	1,127	0
Level 3 investments - end of period	$ 35,987	$ 23,896	$ 35,987	$ 23,896

Fair value measurements (Narrat

Fair value measurements (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Trading Securities	$ 8,976,591	$ 8,845,343
Managed investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Trading Securities	5,942,507	6,119,228
Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Trading Securities	$ 8,976,591	8,845,343
Recurring | Fund of hedge funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment Time Lag Reporting	3 months
Recurring | Hedge funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment Time Lag Reporting	3 months
Recurring | Minimum | Private equity investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment Time Lag Reporting	3 months
Recurring | Minimum | Fixed income investment funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment Time Lag Reporting	1 month
Recurring | Maximum | Private equity investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment Time Lag Reporting	6 months
Recurring | Maximum | Fixed income investment funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment Time Lag Reporting	3 months
Recurring | Managed investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Trading Securities	$ 5,942,507	6,119,228
Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Trading Securities	345,483	330,970
Recurring | Level 3 | Managed investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Trading Securities	$ 276,774	$ 282,595
Ratio of Level 3 investments to total investments (percent)	4.70%	4.60%

Variable interest entities (Not

Variable interest entities (Notes payable to AlphaCat investors) (Details) - Variable interest entities, primary beneficiary - AlphaCat ILS funds - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Variable Interest Entity [Line Items]
Notes payable to AlphaCat investors, beginning of period	$ 1,066,159	$ 370,982	$ 278,202	$ 75,493	$ 75,493
Notes payable to AlphaCat investors recognized on deconsolidation of AlphaCat ILS fund			423,269
Issuance of notes payable to AlphaCat investors	59,530	13,808	773,607	406,239
Redemption of notes payable to AlphaCat investors	(18,627)	(12,028)	(367,733)	(109,712)
Foreign exchange gains	556	(32)	273	710
Notes payable to AlphaCat investors, end of period	1,107,618	372,730	1,107,618	372,730	278,202
Variable Funding Notes
Variable Interest Entity [Line Items]
Notes payable to AlphaCat investors, beginning of period	893,959	276,656	278,202	75,493	75,493
Notes payable to AlphaCat investors recognized on deconsolidation of AlphaCat ILS fund			423,269
Issuance of notes payable to AlphaCat investors	59,530	13,808	601,407	311,913
Redemption of notes payable to AlphaCat investors	(18,627)	(12,028)	(367,733)	(109,712)
Foreign exchange gains	556	(32)	273	710
Notes payable to AlphaCat investors, end of period	935,418	278,404	935,418	278,404	278,202
Structured Notes
Variable Interest Entity [Line Items]
Notes payable to AlphaCat investors, beginning of period	172,200	94,326	0	0	0
Notes payable to AlphaCat investors recognized on deconsolidation of AlphaCat ILS fund			0
Issuance of notes payable to AlphaCat investors	0	0	172,200	94,326
Redemption of notes payable to AlphaCat investors	0	0	0	0
Foreign exchange gains	0	0	0	0
Notes payable to AlphaCat investors, end of period	$ 172,200	$ 94,326	$ 172,200	$ 94,326	$ 0

Variable interest entities (Ass

Variable interest entities (Assets and liabilities of consolidated VIEs) (Details) - Variable interest entities, primary beneficiary - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
AlphaCat sidecars
Variable Interest Entity [Line Items]
Total assets		$ 30,598	$ 40,041
Total liabilities		3,708	3,206
AlphaCat ILS funds - Lower Risk
Variable Interest Entity [Line Items]
Total assets	[1]	1,019,072	1,498,276
Total liabilities	[1]	234,192	42,457
AlphaCat ILS funds - Higher Risk
Variable Interest Entity [Line Items]
Total assets	[1]	947,135	972,633
Total liabilities	[1]	541,466	381,332
AlphaCat Re and AlphaCat Master Fund
Variable Interest Entity [Line Items]
Total assets		3,427,625	2,510,415
Total liabilities		3,427,455	2,510,245
BetaCat ILS funds
Variable Interest Entity [Line Items]
Total assets		144,766	82,471
Total liabilities		$ 291	$ 30,663
[1]	Lower risk AlphaCat ILS funds have a maximum permitted portfolio expected loss of less than 7%, whereas higher risk AlphaCat ILS funds have a maximum permitted portfolio expected loss of greater than 7%. Expected loss represents the average annual loss over the set of simulation scenarios divided by the total limit.

Variable interest entities (Nar

Variable interest entities (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017USD ($)fundssubsidiaries	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)fundssubsidiaries	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)
Variable Interest Entity [Line Items]
Loss on deconsolidation of AlphaCat ILS fund			$ (402)	$ 0
(Loss) income attributable to AlphaCat investors	$ (74,130)	$ 5,564	(54,797)	16,278
Accounts payable and accrued expenses
Variable Interest Entity [Line Items]
(Loss) income attributable to AlphaCat investors			$ 9,737	17,068
Variable interest entities, primary beneficiary
Variable Interest Entity [Line Items]
Variable funding notes, typical minimum duration			12 months
AlphaCat ILS funds | Variable interest entities, primary beneficiary
Variable Interest Entity [Line Items]
Variable Interest Entity Redemption Of Notes Payable To AlphaCat Investors	$ 18,627	12,028	$ 367,733	$ 109,712
Risk profile percentage			7.00%
AlphaCat ILS funds | Variable interest entities, primary beneficiary | Accounts payable and accrued expenses
Variable Interest Entity [Line Items]
Variable Interest Entity Redemption Of Notes Payable To AlphaCat Investors					$ 1,000
ILS fund issuing structured notes
Variable Interest Entity [Line Items]
Number of AlphaCat ILS funds | funds	1		1
BetaCat ILS funds | Variable interest entities, primary beneficiary
Variable Interest Entity [Line Items]
Number of consolidated VIE BetaCat ILS funds | subsidiaries	2		2
Structured Notes
Variable Interest Entity [Line Items]
Structured notes interest rate percentage			7.00%	8.00%
Structured Notes | AlphaCat ILS funds | Variable interest entities, primary beneficiary
Variable Interest Entity [Line Items]
Variable Interest Entity Redemption Of Notes Payable To AlphaCat Investors	$ 0	$ 0	$ 0	$ 0

Noncontrolling interest (Detail

Noncontrolling interest (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Noncontrolling Interest [Line Items]
Balance, beginning of period	$ 1,667,318	$ 1,744,437	$ 1,693,978	$ 1,266,376
Issuance of shares	26,999	700	495,499	553,624
Adjustment to noncontrolling interests as a result of deconsolidation			(459,021)	0
(Loss) income attributable to noncontrolling interests	(376,366)	37,439	(290,144)	96,163
Redemption of shares	(105,124)	0	(227,485)	(133,587)
Balance, end of period	1,212,827	1,782,576	1,212,827	1,782,576
Redeemable noncontrolling interest
Noncontrolling Interest [Line Items]
Balance, beginning of period	1,251,660	1,532,283	1,528,001	1,111,714
Issuance of shares	26,999	700	237,199	381,950
Adjustment to noncontrolling interests as a result of deconsolidation			(459,021)	0
(Loss) income attributable to noncontrolling interests	(140,781)	26,597	(86,296)	72,400
Redemption of shares	(3,998)	0	(86,003)	(6,484)
Balance, end of period	1,133,880	1,559,580	1,133,880	1,559,580
Balances payable to noncontrolling interests	0		0		$ 71,530
Noncontrolling interest
Noncontrolling Interest [Line Items]
Balance, beginning of period	415,658	212,154	165,977	154,662
Issuance of shares	0	0	258,300	171,674
Adjustment to noncontrolling interests as a result of deconsolidation			0	0
(Loss) income attributable to noncontrolling interests	(235,585)	10,842	(203,848)	23,763
Distributions	(101,126)	0	(141,482)	(127,103)
Balance, end of period	78,947	$ 222,996	78,947	$ 222,996
Balances payable to noncontrolling interests	$ 0		$ 0		$ 16,144

Derivative instruments (Amount

Derivative instruments (Amount and balance sheet location) (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Not designated as hedging instruments | Foreign exchange contracts
Summary of derivatives
Net Notional Exposure		$ 267,206	$ 181,375
Not designated as hedging instruments | Foreign exchange contracts | Other assets
Summary of derivatives
Fair value, derivative assets	[1]	1,522	2,351
Not designated as hedging instruments | Foreign exchange contracts | Accounts payable and accrued expenses
Summary of derivatives
Fair value, derivative liabilities	[1]	1,379	3,421
Not designated as hedging instruments | Interest rate swap contracts
Summary of derivatives
Net Notional Exposure		200,000	0
Not designated as hedging instruments | Interest rate swap contracts | Other assets
Summary of derivatives
Fair value, derivative assets	[1]	440	0
Not designated as hedging instruments | Interest rate swap contracts | Accounts payable and accrued expenses
Summary of derivatives
Fair value, derivative liabilities	[1]	1,607	0
Designated as hedging instruments | Interest rate swap contracts
Summary of derivatives
Net Notional Exposure		552,263	552,263
Designated as hedging instruments | Interest rate swap contracts | Other assets
Summary of derivatives
Fair value, derivative assets	[2]	20	20
Designated as hedging instruments | Interest rate swap contracts | Accounts payable and accrued expenses
Summary of derivatives
Fair value, derivative liabilities	[2]	$ 1,347	$ 1,479
[1]	Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses, respectively, within the Company’s consolidated balance sheets.
[2]	Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses, respectively, within the Company’s consolidated balance sheets.

Derivative instruments (Amoun62

Derivative instruments (Amount included in statement of operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Not designated as hedging instruments | Foreign exchange gains (losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses) recognized in earnings	$ (1,927)	$ 1,326	$ (7,999)	$ 209
Not designated as hedging instruments | Other income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses) recognized in earnings	0	(155)	(979)	(35)
Not designated as hedging instruments | Gain (Loss) on Investments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses) recognized in earnings	(848)	566	(1,167)	566
Designated as hedging instruments | Cash flow hedge | Interest rate swap contracts
Derivative instruments designated as a cash flow hedge
Amount of ineffective portion excluded from effectiveness testing	13	(438)	(33)	(1,132)
Designated as hedging instruments | Cash flow hedge | Interest rate swap contracts | Other comprehensive income
Derivative instruments designated as a cash flow hedge
Amount of effective portion recognized in other comprehensive income	1,918	3,155	6,294	9,505
Designated as hedging instruments | Cash flow hedge | Interest rate swap contracts | Finance expenses
Derivative instruments designated as a cash flow hedge
Amount of effective portion subsequently reclassified to earnings	$ (1,931)	$ (2,717)	$ (6,261)	$ (8,373)

Reserve for losses and loss e63

Reserve for losses and loss expenses (Components of reserves for losses and loss expenses) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Insurance Loss Reserves [Abstract]
Case reserves	$ 1,271,580		$ 1,237,772
IBNR	3,664,057		1,757,423
Reserve for losses and loss expenses	$ 4,935,637	$ 3,305,191	$ 2,995,195	$ 3,035,987	$ 3,122,717	$ 2,996,567

Reserve for losses and loss e64

Reserve for losses and loss expenses (Reserve rollforward) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reserve for paid losses and unpaid loss expenses
Reserve for losses and loss expenses, beginning of period		$ 3,305,191	$ 3,122,717	$ 2,995,195	$ 2,996,567
Loss reserves recoverable, beginning of period		(600,207)	(442,987)	(430,421)	(350,586)
Net reserves for losses and loss expenses, beginning of period		2,704,984	2,679,730	2,564,774	2,645,981
Net reserves acquired	[1]	0	0	23,753	0
Increase (decrease) in net losses and loss expenses incurred in respect of losses occurring in:
Current year		1,329,666	311,279	1,999,921	959,376
Prior years		(75,064)	(52,885)	(179,585)	(169,405)
Total incurred losses and loss expenses		1,254,602	258,394	1,820,336	789,971
Less net losses and loss expenses paid in respect of losses occurring in:
Current year		(191,612)	(178,707)	(242,068)	(240,362)
Prior years		(181,094)	(166,539)	(612,448)	(596,618)
Total net paid losses		(372,706)	(345,246)	(854,516)	(836,980)
Foreign exchange losses (gains)		13,741	(1,500)	46,274	(7,594)
Net reserve for losses and loss expenses, end of period		3,600,621	2,591,378	3,600,621	2,591,378
Loss reserves recoverable, end of period		1,335,016	444,609	1,335,016	444,609
Reserve for losses and loss expenses, end of period		4,935,637	3,035,987	4,935,637	3,035,987
Components of incurred losses and loss expenses
Gross losses and loss expenses		2,104,914	284,413	2,866,722	952,129
Reinsurance recoverable		(850,312)	(26,019)	(1,046,386)	(162,158)
Net incurred losses and loss expenses		1,254,602	$ 258,394	1,820,336	$ 789,971
Net loss reserves		$ 42,575		42,575
Commutation of reserves				$ 18,822
[1]	Equals net reserves acquired of $42,575 less net reserves commuted at closing of $18,822.

Reserve for losses and loss e65

Reserve for losses and loss expenses (Prior year development) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	$ (75,064)	$ (52,885)	$ (179,585)	$ (169,405)
Loss events
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(16,100)	(20,300)	(31,500)	(9,000)
Attritional losses
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(58,900)	(32,600)	(148,000)	(160,400)
Validus Re
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(48,137)	(33,033)	(100,016)	(89,594)
Talbot
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(23,614)	(18,691)	(68,304)	(69,739)
Western World
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(62)	(880)	(744)	(8,464)
AlphaCat
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(3,251)	(281)	(10,521)	(1,608)
Property
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(36,131)	(22,983)	(62,395)	(86,323)
Property | Validus Re
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(26,372)	(19,736)	(30,614)	(52,036)
Property | Talbot
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(8,752)	(2,429)	(19,980)	(30,969)
Property | Western World
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	464	(553)	(2,838)	(2,576)
Property | AlphaCat
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(1,471)	(265)	(8,963)	(742)
Marine
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(9,842)	(13,051)	(74,636)	(25,478)
Marine | Validus Re
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(7,105)	(8,504)	(38,847)	(14,967)
Marine | Talbot
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(2,737)	(4,547)	(35,789)	(10,511)
Specialty
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(28,565)	(16,524)	(44,648)	(51,716)
Specialty | Validus Re
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(14,660)	(4,793)	(30,555)	(22,591)
Specialty | Talbot
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(12,125)	(11,715)	(12,535)	(28,259)
Specialty | AlphaCat
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(1,780)	(16)	(1,558)	(866)
Liability
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	(526)	(327)	2,094	(5,888)
Liability | Western World
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net (favorable) adverse development on prior years	$ (526)	$ (327)	$ 2,094	$ (5,888)

Reinsurance (Components of rein

Reinsurance (Components of reinsurance) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Reinsurance Disclosures [Abstract]
Outstanding losses	$ 207,368		$ 165,328
IBNR	1,127,648		265,093
Total loss reserves recoverable	1,335,016	$ 600,207	430,421	$ 444,609	$ 442,987	$ 350,586
Paid losses recoverable	77,730		35,247
Total reinsurance balances recoverable	$ 1,412,746		$ 465,668

Reinsurance (Ceded credit risk)

Reinsurance (Ceded credit risk) (Details) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Ceded Credit Risk [Line Items]
Provision for uncollectible reinsurance relating to losses recoverable		$ 8,326	$ 5,153
Reinsurance Recoverable
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 1,412,746	$ 465,668
Percentage of total		100.00%	100.00%
Reinsurance Recoverable | A- or better
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 1,400,430	$ 461,369
Percentage of total		99.10%	99.10%
Reinsurance Recoverable | Top 10 reinsurers
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 1,208,003	$ 395,308
Percentage of total		85.50%	84.90%
Reinsurance Recoverable | Top 10 reinsurers | Fully collateralized reinsurers | NR
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 564,714	$ 83,088
Percentage of total		40.00%	17.80%
Reinsurance Recoverable | Top 10 reinsurers | Munich Re | AA- rating
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 164,131	$ 18,214
Percentage of total		11.60%	3.90%
Reinsurance Recoverable | Top 10 reinsurers | Everest Re | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 95,759	$ 36,912
Percentage of total		6.80%	7.90%
Reinsurance Recoverable | Top 10 reinsurers | Lloyds Syndicates | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 94,845	$ 84,419
Percentage of total		6.70%	18.20%
Reinsurance Recoverable | Top 10 reinsurers | Swiss Re | AA- rating
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 81,921	$ 84,044
Percentage of total		5.80%	18.10%
Reinsurance Recoverable | Top 10 reinsurers | Hannover Re | AA- rating
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 62,715	$ 50,603
Percentage of total		4.40%	10.90%
Reinsurance Recoverable | Top 10 reinsurers | Federal Crop Insurance Corporation
Ceded Credit Risk [Line Items]
Reinsurance recoverable	[1]	$ 49,503
Percentage of total	[1]	3.50%
Reinsurance Recoverable | Top 10 reinsurers | Qatar Insurance Company | A rating
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 38,061
Percentage of total		2.70%
Reinsurance Recoverable | Top 10 reinsurers | Transatlantic Re | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 29,795	$ 10,593
Percentage of total		2.10%	2.30%
Reinsurance Recoverable | Top 10 reinsurers | XL Catlin | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 26,559
Percentage of total		1.90%
Reinsurance Recoverable | Top 10 reinsurers | Hamilton Re | A- rating
Ceded Credit Risk [Line Items]
Reinsurance recoverable			$ 10,343
Percentage of total			2.20%
Reinsurance Recoverable | Top 10 reinsurers | Toa Re | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable			$ 9,510
Percentage of total			2.00%
Reinsurance Recoverable | Top 10 reinsurers | National Indemnity | AA plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable			$ 7,582
Percentage of total			1.60%
Reinsurance Recoverable | Other reinsurers' balances greater than $1 million
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 198,774	$ 66,944
Percentage of total		14.10%	14.40%
Reinsurance Recoverable | Other reinsurers' balances less than $1 million
Ceded Credit Risk [Line Items]
Reinsurance recoverable		$ 5,969	$ 3,416
Percentage of total		0.40%	0.70%
[1]	The Company participates in a crop reinsurance program sponsored by the U.S. federal government. The Company remains obligated for amounts ceded in the event that its reinsurers or retrocessionaires do not meet their obligations, except for amounts ceded to the U.S. federal government in the agriculture line of business.

Share capital (Preferred stock)

Share capital (Preferred stock) (Details) $ / shares in Units, $ in Thousands	Jun. 12, 2017USD ($)$ / sharesshares	Jun. 13, 2016$ / sharesshares	Sep. 30, 2017USD ($)shares	Sep. 30, 2016USD ($)shares
Preferred shares - Shareholders' Equity
Net proceeds on issuance of preferred shares | $			$ 241,686	$ 144,852
Preferred shares, shares issued, beginning of period | shares			6,000	0
Preferred shares, shares outstanding, beginning of period | shares			6,000	0
Preferred shares issued | shares			10,000	6,000
Preferred shares, shares issued, end of period | shares			16,000	6,000
Preferred shares, shares outstanding, end of period | shares			16,000	6,000
Series A preferred shares
Preferred shares - Shareholders' Equity
Preferred shares, dividend rate, percentage		5.875%
Proportionate interest of preferred shares, per depositary share		0.001
Preferred stock, par or stated value per share | $ / shares		$ 0.175
Preferred stock, liquidation preference, per share | $ / shares		$ 25,000
Preferred shares, shares issued, beginning of period | shares			6,000
Preferred shares issued | shares		6,000
Preferred shares, shares issued, end of period | shares			6,000
Series A depositary share equivalent
Preferred shares - Shareholders' Equity
Preferred shares equivalent depositary shares number | shares		6,000,000
Preferred stock, liquidation preference, per share | $ / shares		$ 25
Series B preferred shares
Preferred shares - Shareholders' Equity
Preferred shares, dividend rate, percentage	5.80%
Proportionate interest of preferred shares, per depositary share	0.001
Preferred stock, par or stated value per share | $ / shares	$ 0.175
Preferred stock, liquidation preference, per share | $ / shares	$ 25,000
Net proceeds on issuance of preferred shares | $	$ 241,686
Preferred shares issued | shares	10,000
Preferred shares, shares issued, end of period | shares			10,000
Series B preferred shares | On or after June 21, 2022
Preferred shares - Shareholders' Equity
Preferred shares, redemption price per share | $ / shares	$ 25,000
Series B preferred shares | Prior to redemption in the event of amalgamation, consolidation, merger or similar
Preferred shares - Shareholders' Equity
Preferred shares, redemption price per share | $ / shares	26,000
Series B preferred shares | Prior to redemption if change in tax law or capital disqualification event
Preferred shares - Shareholders' Equity
Preferred shares, redemption price per share | $ / shares	$ 25,000
Series B depositary share equivalent
Preferred shares - Shareholders' Equity
Preferred shares equivalent depositary shares number | shares	10,000,000
Preferred stock, liquidation preference, per share | $ / shares	$ 25
Series B depositary share equivalent | On or after June 21, 2022
Preferred shares - Shareholders' Equity
Preferred shares, redemption price per share | $ / shares	25
Series B depositary share equivalent | Prior to redemption in the event of amalgamation, consolidation, merger or similar
Preferred shares - Shareholders' Equity
Preferred shares, redemption price per share | $ / shares	26
Series B depositary share equivalent | Prior to redemption if change in tax law or capital disqualification event
Preferred shares - Shareholders' Equity
Preferred shares, redemption price per share | $ / shares	$ 25

Share capital (Common stock) (D

Share capital (Common stock) (Details) - USD ($) $ / shares in Units, $ in Thousands	Feb. 03, 2015	Sep. 30, 2017	Sep. 30, 2016
Share Capital (Narrative)
Authorized share capital		571,428,571
Common shares, par value		$ 0.175
Common stock voting rights		one vote per share
Restriction on percentage of voting power		9.09%
Share repurchases
Common share repurchase authorization	$ 750,000
Share repurchase program, cumulative shares repurchased		80,860,661
Shares repurchased, cumulative	$ 2,274,401	$ 2,722,749
Remaining share repurchase authorization amount		$ 301,652
Summary of common shares issued and outstanding
Common shares issued, beginning balance		161,279,976	160,570,772
Options exercised		0	27,983
Common shares issued, ending balance		161,956,886	161,273,353
Treasury shares, end of period		82,499,633	81,830,323
Common shares outstanding, ending balance		79,457,253	79,443,030
Restricted share awards
Summary of common shares issued and outstanding
Vested, net of shares withheld		619,046	608,024
Restricted share units
Summary of common shares issued and outstanding
Vested, net of shares withheld		15,454	18,486
Performance shares
Summary of common shares issued and outstanding
Vested, net of shares withheld		42,410	48,088

Share capital (Dividends) (Deta

Share capital (Dividends) (Details) - $ / shares	3 Months Ended						9 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2017	Sep. 30, 2016
Class of Stock [Line Items]
Cash dividends declared per share - common shares	$ 0.38	$ 0.38	$ 0.38	$ 0.35	$ 0.35	$ 0.35	$ 1.14	$ 1.05
Series A depositary share equivalent
Class of Stock [Line Items]
Cash dividends declared per share - preferred shares	0.3671875	$ 0.3671875	$ 0.3671875	$ 0.3753472
Series B depositary share equivalent
Class of Stock [Line Items]
Cash dividends declared per share - preferred shares	$ 0.3423611

Stock plans (Options activity)

Stock plans (Options activity) (Details) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Options activities:
Options outstanding, beginning balance (in shares)	26,136	65,401
Options exercised during period (in shares)	0	(35,351)
Options outstanding, ending balance (in shares)	26,136	30,050
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, beginning balance (in dollars per share)	$ 6.78	$ 7.74
Weighted average grant date fair value, options exercised (in dollars per share)	0	8.16
Weighted average grant date fair value, ending balance (in dollars per share)	6.78	7.24
Weighted Average Grant Date Exercise Price
Weighted average grant date exercise price, beginning balance (in dollars per share)	23.48	20.17
Weighted average grant date exercise price, options exercised (in dollars per share)	0	17.82
Weighted average grant date exercise price, ending balance (in dollars per share)	$ 23.48	$ 22.93

Stock plans (Other awards activ

Stock plans (Other awards activity) (Details) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Restricted share awards
Activities
Beginning balance (in shares)	2,469,982	2,739,446
Granted (in shares)	508,186	559,516
Vested (in shares)	(828,800)	(789,547)
Forfeited (in shares)	(53,775)	(33,070)
Ending balance (in shares)	2,095,593	2,476,345
Weighted average grant date fair value
Weighted average grant date fair value, beginning balance (in dollars per share)	$ 40.89	$ 38.25
Weighted average grant date fair value, granted (in dollars per share)	53.25	48.78
Weighted average grant date fair value, vested (in dollars per share)	41.25	37.36
Weighted average grant date fair value, forfeited (in dollars per share)	43.38	40.25
Weighted average grant date fair value, ending balance (in dollars per share)	$ 43.69	$ 40.88
Restricted share units
Activities
Beginning balance (in shares)	112,808	114,337
Granted (in shares)	12,236	21,609
Vested (in shares)	(18,748)	(23,982)
Issued in lieu of cash dividends (in shares)	2,260	2,436
Forfeited (in shares)	0	(8,338)
Ending balance (in shares)	108,556	106,062
Weighted average grant date fair value
Weighted average grant date fair value, beginning balance (in dollars per share)	$ 40.95	$ 38.47
Weighted average grant date fair value, granted (in dollars per share)	53.40	48.83
Weighted average grant date fair value, vested (in dollars per share)	41.91	38.18
Weighted average grant date fair value, issued in lieu of cash dividends (in dollars per share)	41.42	39.10
Weighted average grant date fair value, forfeited (in dollars per share)	0	44.34
Weighted average grant date fair value, ending balance (in dollars per share)	$ 42.20	$ 40.20
Performance shares
Activities
Beginning balance (in shares)	285,820	172,594
Granted (in shares)	107,209	125,290
Vested (in shares)	(52,639)	(57,581)
Conversion adjustment (in shares)	(26,322)	45,517
Ending balance (in shares)	314,068	285,820
Weighted average grant date fair value
Weighted average grant date fair value, beginning balance (in dollars per share)	$ 44.53	$ 40.70
Weighted average grant date fair value, granted (in dollars per share)	53.40	48.75
Weighted average grant date fair value, vested (in dollars per share)	37.33	36.11
Weighted average grant date fair value, conversion adjustment (in dollars per share)	36.82	36.82
Weighted average grant date fair value, ending balance (in dollars per share)	$ 49.37	$ 44.53

Stock plans (Components of shar

Stock plans (Components of share compensation expenses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Total share compensation expenses
Share compensation expenses	$ 9,443	$ 10,501	$ 30,080	$ 32,465
Restricted share awards
Total share compensation expenses
Share compensation expenses	7,814	9,159	26,603	27,805
Restricted share units
Total share compensation expenses
Share compensation expenses	340	290	982	978
Performance shares
Total share compensation expenses
Share compensation expenses	$ 1,289	$ 1,052	$ 2,495	$ 3,682

Stock plans (Narrative) (Detail

Stock plans (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Stock plans (other details)
Number of shares reserved for issuance under the LTIP and STIP	2,753,292		2,753,292
Remaining number of shares reserved for issuance	701,617		701,617
Share compensation expenses	$ 9,443	$ 10,501	$ 30,080	$ 32,465
Options exercised during period (in shares)			0	(35,351)
Share Based Compensation Arrangement By Share Based Payment Award Options Exercised In Period Weighted Average Grant Date Fair Value			$ 0	$ 8.16
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price			$ 0	$ 17.82
Options
Stock plans (other details)
Life of options			10 years
Restricted share awards
Stock plans (other details)
Share compensation expenses	7,814	9,159	$ 26,603	$ 27,805
Unrecognized share compensation expenses	57,065		$ 57,065		$ 58,804
Weighted average period of recognizing share based compensation expenses			2 years 5 months 12 days		2 years 3 months 3 days
Restricted share units
Stock plans (other details)
Share compensation expenses	340	290	$ 982	978
Unrecognized share compensation expenses	2,233		$ 2,233		$ 2,542
Weighted average period of recognizing share based compensation expenses			2 years 5 months 23 days		2 years 6 months 21 days
Performance shares
Stock plans (other details)
Share compensation expenses	1,289	$ 1,052	$ 2,495	$ 3,682
Unrecognized share compensation expenses	$ 9,031		$ 9,031		$ 6,902
Weighted average period of recognizing share based compensation expenses			2 years 1 month 17 days		2 years 21 days
Performance share awards performance period			3 years

Debt and financing arrangemen75

Debt and financing arrangements (Summary of outstanding debentures and senior notes payable) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Debt Instruments [Line Items]
Debentures payable	$ 538,910	$ 537,226
Debt instrument, commitment	250,000	250,000
Less: Unamortized debt issuance costs	(4,487)	(4,638)
Total senior notes payable	245,513	245,362
Debentures payable	784,423	782,588
2006 Junior Subordinated
Debt Instruments [Line Items]
Debentures payable	150,000	150,000
Debt instrument, commitment	150,000
2007 Junior Subordinated
Debt Instruments [Line Items]
Debentures payable	139,800	139,800
Debt instrument, commitment	200,000
Flagstone 2006 Junior Subordinated
Debt Instruments [Line Items]
Debentures payable	135,360	133,676
Debt instrument, commitment	135,360
Flagstone 2007 Junior Subordinated
Debt Instruments [Line Items]
Debentures payable	$ 113,750	$ 113,750

Debt and financing arrangemen76

Debt and financing arrangements (Summary of key terms of senior notes and debentures) (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Debt Instruments [Line Items]
Commitment		$ 250,000	$ 250,000
Junior Subordinated Debt
Debt Instruments [Line Items]
Payments expected to be made after 2022		$ 538,910
2006 Junior Subordinated
Debt Instruments [Line Items]
Issuance date		Jun. 15, 2006
Commitment		$ 150,000
Maturity date		Jun. 15, 2036
Interest payments due		Quarterly
Interest rate term		5 years
2006 Junior Subordinated | Three month LIBOR
Debt Instruments [Line Items]
Spread on variable rate (in percent)		3.55%
Flagstone 2006 Junior Subordinated
Debt Instruments [Line Items]
Issuance date		Aug. 23, 2006
Commitment		$ 135,360
Maturity date		Sep. 15, 2036
Interest payments due		Quarterly
2007 Junior Subordinated
Debt Instruments [Line Items]
Issuance date		Jun. 21, 2007
Commitment		$ 200,000
Maturity date		Jun. 15, 2037
Interest payments due		Quarterly
Interest rate term		5 years
2007 Junior Subordinated | Three month LIBOR
Debt Instruments [Line Items]
Spread on variable rate (in percent)		2.95%
Flagstone 2007 Due July 30 2037
Debt Instruments [Line Items]
Issuance date		Jun. 8, 2007
Commitment		$ 100,000
Maturity date		Jul. 30, 2037
Interest payments due		Quarterly
Flagstone 2007 Due September 15 2037
Debt Instruments [Line Items]
Issuance date		Sep. 20, 2007
Commitment		$ 25,000
Maturity date		Sep. 15, 2037
Interest payments due		Quarterly
2010 Senior Notes Due 2040
Debt Instruments [Line Items]
Issuance date		Jan. 26, 2010
Commitment		$ 250,000
Maturity date		Jan. 26, 2040
Interest payments due		Semi-annually in arrears
Payments expected to be made after 2022		$ 250,000
At Issuance | 2006 Junior Subordinated
Debt Instruments [Line Items]
Fixed interest rate (in percent)	[1]	9.069%
At Issuance | Flagstone 2006 Junior Subordinated | Three month LIBOR
Debt Instruments [Line Items]
Spread on variable rate (in percent)	[2]	3.54%
At Issuance | 2007 Junior Subordinated
Debt Instruments [Line Items]
Fixed interest rate (in percent)	[3]	8.48%
At Issuance | Flagstone 2007 Due July 30 2037 | Three month LIBOR
Debt Instruments [Line Items]
Spread on variable rate (in percent)	[2]	3.00%
At Issuance | Flagstone 2007 Due September 15 2037 | Three month LIBOR
Debt Instruments [Line Items]
Spread on variable rate (in percent)	[2]	3.10%
At Issuance | 2010 Senior Notes Due 2040
Debt Instruments [Line Items]
Fixed interest rate (in percent)	[4]	8.875%
Outstanding | 2006 Junior Subordinated
Debt Instruments [Line Items]
Effective percentage	[5]	5.831%
Outstanding | Flagstone 2006 Junior Subordinated
Debt Instruments [Line Items]
Effective percentage	[5]	6.463%
Outstanding | 2007 Junior Subordinated
Debt Instruments [Line Items]
Effective percentage	[5]	5.18%
Outstanding | Flagstone 2007 Due July 30 2037
Debt Instruments [Line Items]
Effective percentage	[5]	5.90%
Outstanding | Flagstone 2007 Due September 15 2037
Debt Instruments [Line Items]
Effective percentage	[5]	5.983%
Outstanding | 2010 Senior Notes Due 2040
Debt Instruments [Line Items]
Fixed interest rate (in percent)	[4]	8.875%
[1]	Fixed interest rate for 5 years, floating interest rate of three-month LIBOR plus 3.550% thereafter, reset quarterly.
[2]	Floating interest rate of three-month LIBOR plus amount stated, reset quarterly.
[3]	Fixed interest rate for 5 years, floating interest rate of three-month LIBOR plus 2.950% thereafter, reset quarterly.
[4]	Fixed interest rate.
[5]	Fixed interest rate as a result of interest rate swap contracts entered into by the Company.

Debt and financing arrangemen77

Debt and financing arrangements (Credit facilities outstanding) (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Aug. 07, 2017	Dec. 31, 2016
Line of Credit Facility [Line Items]
Commitment		$ 835,000		$ 690,000
Outstanding	[1]	358,361		311,163
Drawn	[2]	165,000
Cash and investments pledged as collateral		265,089		442,184
$85,000 syndicated unsecured letter of credit facility
Line of Credit Facility [Line Items]
Commitment		85,000		85,000
Outstanding	[1]	0		0
Cash and investments pledged as collateral				0
$300,000 syndicated secured letter of credit facility
Line of Credit Facility [Line Items]
Commitment		300,000		300,000
Outstanding	[1]	89,449		121,428
Cash and investments pledged as collateral		108,265		157,597
$24,000 secured bi-lateral letter of credit facility
Line of Credit Facility [Line Items]
Commitment		24,000		24,000
Outstanding	[1]	5,767		4,553
Cash and investments pledged as collateral		22,342		48,097
$20,000 AlphaCat Re secured letter of credit facility
Line of Credit Facility [Line Items]
Commitment	[3]			20,000
Outstanding	[1],[3]			20,000
Cash and investments pledged as collateral	[3]			20,032
$25,000 IPC bi-lateral facility
Line of Credit Facility [Line Items]
Commitment		25,000		25,000
Outstanding	[1]	7,755		8,807
Cash and investments pledged as collateral				0
$236,000 Flagstone bi-lateral facility
Line of Credit Facility [Line Items]
Commitment		236,000		236,000
Outstanding	[1]	90,390		156,375
Cash and investments pledged as collateral		134,482		$ 216,458
$65,000 unsecured revolving credit facility
Line of Credit Facility [Line Items]
Commitment		65,000	$ 65,000
Outstanding	[1]	65,000
Drawn	[2]	65,000
$100,000 unsecured revolving credit facility
Line of Credit Facility [Line Items]
Commitment		100,000	$ 100,000
Outstanding	[1]	100,000
Drawn	[2]	$ 100,000
[1]	Indicates utilization of commitment amount, not drawn borrowings.
[2]	Represents drawn borrowings included in accounts payable and accrued expenses.
[3]	The Company terminated its AlphaCat Re secured letter of credit facility on January 6, 2017.

Debt and financing arrangemen78

Debt and financing arrangements (Components of finance expenses) (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2017		Sep. 30, 2016		Sep. 30, 2017	Sep. 30, 2016
Debt Instruments [Line Items]
Finance expenses	$ 14,523		$ 14,521		$ 42,675	$ 43,890
2006 Junior Subordinated
Debt Instruments [Line Items]
Finance expenses	2,235		2,135		6,633	6,557
2007 Junior Subordinated
Debt Instruments [Line Items]
Finance expenses	1,851		1,851		5,492	5,512
Flagstone 2006 Junior Subordinated
Debt Instruments [Line Items]
Finance expenses	2,272		2,271		6,741	6,760
Flagstone 2007 Junior Subordinated
Debt Instruments [Line Items]
Finance expenses	1,775		1,784		5,249	5,317
2010 Senior Notes Due 2040
Debt Instruments [Line Items]
Finance expenses	5,597		5,597		16,792	16,791
Credit facilities
Debt Instruments [Line Items]
Finance expenses	575		463		1,196	1,359
Bank and other charges
Debt Instruments [Line Items]
Finance expenses	183		276		465	489
AlphaCat fees
Debt Instruments [Line Items]
Finance expenses	$ 35	[1]	$ 144	[1]	$ 107	$ 1,105
[1]	Includes finance expenses incurred by AlphaCat Managers Ltd. in relation to fund raising for the AlphaCat sidecars, the AlphaCat ILS funds and AlphaCat direct.

Debt and financing arrangemen79

Debt and financing arrangements (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Aug. 07, 2017	Dec. 31, 2016
Line of Credit Facility [Line Items]
Commitment	$ 835,000		$ 690,000
Credit Facilities
Line of Credit Facility [Line Items]
Minimum level of consolidated net worth	$ 2,789,131
Percent of consolidated net income quarterly increase under covenant	25.00%
Percent of consolidated shareholders' equity quarterly increase under covenant	50.00%
Ratio consolidated total debt to net worth under covenant	0.35:1.00
$65,000 unsecured revolving credit facility
Line of Credit Facility [Line Items]
Commitment	$ 65,000	$ 65,000
$100,000 unsecured revolving credit facility
Line of Credit Facility [Line Items]
Commitment	$ 100,000	$ 100,000
Federal Funds Rate | $65,000 unsecured revolving credit facility
Line of Credit Facility [Line Items]
Spread on variable rate (in percent)	0.50%
Federal Funds Rate | $100,000 unsecured revolving credit facility
Line of Credit Facility [Line Items]
Spread on variable rate (in percent)	0.50%
Three month LIBOR | $65,000 unsecured revolving credit facility
Line of Credit Facility [Line Items]
Spread on variable rate (in percent)	1.00%
Three month LIBOR | $100,000 unsecured revolving credit facility
Line of Credit Facility [Line Items]
Spread on variable rate (in percent)	1.00%

Accumulated other comprehensi80

Accumulated other comprehensive loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period, net of tax			$ 4,004,268
Total shareholders' equity	$ 4,015,234	$ 4,090,616	4,015,234	$ 4,090,616
Other comprehensive (loss) income	1,494	(2,910)	4,786	(8,523)
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period, net of tax	(19,924)	(18,182)	(23,216)	(12,569)
Net current period other comprehensive loss, net of tax	1,494	(2,910)		(8,523)
Total shareholders' equity	(18,430)	(21,092)	(18,430)	(21,092)
Other comprehensive (loss) income			4,786	(8,523)
Foreign currency translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period, net of tax	(20,188)	(17,149)	(22,274)	(11,834)
Net current period other comprehensive loss, net of tax	1,481	(1,370)	3,567	(6,685)
Total shareholders' equity	(18,707)	(18,519)	(18,707)	(18,519)
Minimum pension liability
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period, net of tax	1,102	730	(150)	334
Net current period other comprehensive loss, net of tax	0	(1,101)	1,252	(705)
Total shareholders' equity	1,102	(371)	1,102	(371)
Cash flow hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period, net of tax	(838)	(1,763)	(792)	(1,069)
Net current period other comprehensive loss, net of tax	13	(439)	(33)	(1,133)
Total shareholders' equity	$ (825)	$ (2,202)	$ (825)	$ (2,202)

Commitments and contingencies81

Commitments and contingencies (Lloyd's syndicate) (Details) - 9 months ended Sep. 30, 2017 - Lloyd's Syndicate 1183 £ in Thousands, $ in Thousands	USD ($)	GBP (£)
Funds at Lloyd's and Lloyd's Central Fund
Maximum premium levies assessable, percent	3.00%	3.00%
Estimated underwriting capacity | £		£ 600,000
Exchange rate	£1 equals $1.34	£1 equals $1.34
Maximum premium levies assessable, amount	$ 24,120
2017 Underwriting Year
Loss Contingencies [Line Items]
Components of required capital	583,600
2016 Underwriting year
Loss Contingencies [Line Items]
Components of required capital	$ 617,000

Commitments and contingencies82

Commitments and contingencies (Other commitments) (Details) - USD ($) $ in Thousands		May 01, 2017	Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Investment commitment
Other Commitments [Line Items]
Capital commitment			$ 313,000	$ 313,000	$ 308,000
Remaining commitment			210,413	210,413	258,704
Investment commitment | Fixed maturity investments
Other Commitments [Line Items]
Remaining commitment	[1]		21,959	21,959	28,499
Investment commitment | Other investments
Other Commitments [Line Items]
Remaining commitment	[2]		101,082	101,082	156,134
Investment commitment | Investments in investment affiliates
Other Commitments [Line Items]
Remaining commitment	[3]		87,372	87,372	64,071
Investment commitment | AlphaCat ILS funds
Other Commitments [Line Items]
Remaining commitment			0	0	$ 10,000
Marketing services agreement
Other Commitments [Line Items]
Annual fee for services commitment		$ 2,000
Services commitment period		7 years
Services commitment extension period		3 years
Marketing expense			$ 500	$ 833
[1]	The Company has an outstanding commitment to participate in certain secured loan facilities through participation agreements with an established loan originator.
[2]	The Company’s total capital commitments related to other investments as at September 30, 2017 was $313,000 (December 31, 2016: $308,000).
[3]	Refer to Note 4(c), “Investments in Investment Affiliates.”

Related party transactions (Det

Related party transactions (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Investments in affiliates		$ 92,079		$ 92,079		$ 100,431
Group Ark Insurance Holdings Ltd
Related Party Transaction [Line Items]
Gross premiums written			$ 1,096		$ 3,067
Reinsurance premiums ceded			41		41
Earned premium adjustments			1,276		2,275
Premiums receivable						292
Loss reserves recoverable						798
Wellington Insurance Company
Related Party Transaction [Line Items]
Gross premiums written		78	0	4,196	0
Earned premium adjustments		943	0	3,480	0
Premiums receivable		468		468		666
Investment affiliate
Related Party Transaction [Line Items]
Investments in affiliates						100,431
Partnership fees incurred		106	$ 520	592	$ 1,535
Investment commitment
Related Party Transaction [Line Items]
Remaining commitment		210,413		210,413		258,704
Investment commitment | Investment affiliate
Related Party Transaction [Line Items]
Remaining commitment	[1]	$ 87,372		$ 87,372		$ 64,071
[1]	Refer to Note 4(c), “Investments in Investment Affiliates.”

Earnings per share (Details)

Earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Basic earnings per share
Net (loss) income (attributable) available to Validus common shareholders	$ (250,446)	$ 89,844	$ (54,790)	$ 351,617
Weighted average number of common shares outstanding	78,994,335	80,134,394	79,132,856	81,635,496
Basic earnings per share available to common shareholders	$ (3.17)	$ 1.12	$ (0.69)	$ 4.31
Earnings per diluted share
Net (loss) income (attributable) available to Validus common shareholders	$ (250,446)	$ 89,844	$ (54,790)	$ 351,617
Weighted average number of common shares outstanding	78,994,335	80,134,394	79,132,856	81,635,496
Weighted average number of diluted common shares outstanding	78,994,335	81,244,556	79,132,856	82,938,624
Earnings per diluted share available to common shareholders	$ (3.17)	$ 1.11	$ (0.69)	$ 4.24
Other details:
Anti-dilutive securities excluded from the calculation of diluted earnings per share		19,808		175,690
Stock options
Earnings per diluted share
Share equivalents	0	26,705	0	32,126
Unvested restricted shares
Earnings per diluted share
Share equivalents	0	1,083,457	0	1,271,002

Segment information (Summary of

Segment information (Summary of results of operating and other segments) (Details) $ in Thousands		3 Months Ended				9 Months Ended
		Sep. 30, 2017USD ($)		Sep. 30, 2016USD ($)		Sep. 30, 2017USD ($)segments	Sep. 30, 2016USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segments						4
Underwriting revenues
Gross premiums written		$ 523,856		$ 372,418		$ 2,507,615	$ 2,309,251
Reinsurance premiums ceded		(116,860)		(45,006)		(373,188)	(249,070)
Net premiums written		406,996		327,412		2,134,427	2,060,181
Change in unearned premiums		316,212		236,363		(204,816)	(351,415)
Net premiums earned		723,208		563,775		1,929,611	1,708,766
Other insurance related income (loss)		3,536		919		5,937	2,400
Segmental revenues		726,744		564,694		1,935,548	1,711,166
Underwriting deductions
Losses and loss expenses		1,254,602		258,394		1,820,336	789,971
Policy acquisition costs		115,590		113,434		344,486	328,593
General and administrative expenses		70,342		82,443		254,615	258,339
Share compensation expenses		9,443		10,501		30,080	32,465
Total underwriting deductions		1,449,977		464,772		2,449,517	1,409,368
Segmental (loss) income		(723,233)		99,922		(513,969)	301,798
Investment (loss) income from AlphaCat Funds and Sidecars		44,458		43,514		128,913	112,232
Other items		(18,887)	[1]	(20,898)	[1]	(56,828)	(36,591)
Dividends on preferred shares		(5,627)		(2,252)		(10,033)	(2,252)
Transaction expenses		0		0		(4,427)	0
Loss (income) attributable to AlphaCat investors		74,130		(5,564)		54,797	(16,278)
Net (income) attributable to noncontrolling interests		376,366		(37,439)		290,144	(96,163)
Finance expenses		14,523		14,521		42,675	43,890
Tax (benefit) expense		(2,632)		1,830		(7,168)	1,418
Net realized gains on investments		906		4,397		2,016	6,537
Change in net unrealized gains on managed investments		(5,197)		5,459		24,472	84,331
Income (loss) from investment affiliates		1,011		453		15,665	(4,249)
Net investment return	[2]	41,178		53,823		171,066	198,851
Foreign exchange gains (losses)		1,404		766		7,164	(11,765)
Net (loss) income (attributable) available to Validus		(244,819)		92,096		(44,757)	353,869
Selected ratios:
Net (loss) income (attributable) available to Validus common shareholders		(250,446)		89,844		(54,790)	351,617
Operating Segments | Validus Re
Underwriting revenues
Gross premiums written		153,890		94,741		1,071,409	1,072,219
Reinsurance premiums ceded		(40,988)		(15,967)		(161,188)	(111,658)
Net premiums written		112,902		78,774		910,221	960,561
Change in unearned premiums		154,145		149,705		(184,155)	(241,129)
Net premiums earned		267,047		228,479		726,066	719,432
Other insurance related income (loss)		68		58		204	(107)
Segmental revenues		267,115		228,537		726,270	719,325
Underwriting deductions
Losses and loss expenses		347,484		98,425		538,323	313,432
Policy acquisition costs		45,422		42,837		133,836	127,660
General and administrative expenses		12,444		17,528		48,550	52,579
Share compensation expenses		2,606		2,695		7,746	8,371
Total underwriting deductions		407,956		161,485		728,455	502,042
Segmental (loss) income		(140,841)		67,052		(2,185)	217,283
Validus share of segmental (loss) income		$ (140,841)		$ 67,052		$ (2,185)	$ 217,283
Selected ratios:
Net premiums written / Gross premiums written		73.40%		83.10%		85.00%	89.60%
Losses and loss expenses		130.10%		43.10%		74.10%	43.60%
Policy acquisition costs		17.00%		18.70%		18.40%	17.70%
General and administrative expenses	[3]	5.70%		8.90%		7.80%	8.50%
Expense ratio		22.70%		27.60%		26.20%	26.20%
Combined ratio		152.80%		70.70%		100.30%	69.80%
Operating Segments | Talbot Segment
Underwriting revenues
Gross premiums written		$ 192,883		$ 189,674		$ 702,535	$ 752,058
Reinsurance premiums ceded		(36,462)		(22,877)		(154,263)	(137,496)
Net premiums written		156,421		166,797		548,272	614,562
Change in unearned premiums		23,191		32,258		18,279	(7,166)
Net premiums earned		179,612		199,055		566,551	607,396
Other insurance related income (loss)		692		99		1,512	389
Segmental revenues		180,304		199,154		568,063	607,785
Underwriting deductions
Losses and loss expenses		178,440		109,860		378,241	319,271
Policy acquisition costs		41,493		46,488		129,074	134,444
General and administrative expenses		23,069		32,333		97,094	109,929
Share compensation expenses		2,310		3,163		8,292	9,955
Total underwriting deductions		245,312		191,844		612,701	573,599
Segmental (loss) income		(65,008)		7,310		(44,638)	34,186
Validus share of segmental (loss) income		$ (65,008)		$ 7,310		$ (44,638)	$ 34,186
Selected ratios:
Net premiums written / Gross premiums written		81.10%		87.90%		78.00%	81.70%
Losses and loss expenses		99.30%		55.20%		66.80%	52.60%
Policy acquisition costs		23.10%		23.40%		22.80%	22.10%
General and administrative expenses	[3]	14.20%		17.80%		18.50%	19.70%
Expense ratio		37.30%		41.20%		41.30%	41.80%
Combined ratio		136.60%		96.40%		108.10%	94.40%
Operating Segments | Western World
Underwriting revenues
Gross premiums written		$ 156,517		$ 85,260		$ 459,628	$ 236,190
Reinsurance premiums ceded		(43,207)		(6,202)		(72,005)	(15,347)
Net premiums written		113,310		79,058		387,623	220,843
Change in unearned premiums		61,603		(8,260)		15,256	(22,890)
Net premiums earned		174,913		70,798		402,879	197,953
Other insurance related income (loss)		662		219		1,566	696
Segmental revenues		175,575		71,017		404,445	198,649
Underwriting deductions
Losses and loss expenses		157,709		45,748		329,642	129,623
Policy acquisition costs		20,721		17,094		60,187	46,704
General and administrative expenses		21,553		10,171		50,623	33,704
Share compensation expenses		354		702		1,655	1,825
Total underwriting deductions		200,337		73,715		442,107	211,856
Segmental (loss) income		(24,762)		(2,698)		(37,662)	(13,207)
Validus share of segmental (loss) income		$ (24,762)		$ (2,698)		$ (37,662)	$ (13,207)
Selected ratios:
Net premiums written / Gross premiums written		72.40%		92.70%		84.30%	93.50%
Losses and loss expenses		90.20%		64.60%		81.80%	65.50%
Policy acquisition costs		11.80%		24.10%		14.90%	23.60%
General and administrative expenses	[3]	12.50%		15.40%		13.00%	17.90%
Expense ratio		24.30%		39.50%		27.90%	41.50%
Combined ratio		114.50%		104.10%		109.70%	107.00%
Operating Segments | AlphaCat
Underwriting revenues
Gross premiums written		$ 27,213		$ 4,413		$ 297,821	$ 270,666
Third party management fees		5,095		7,025		15,288	14,843
Related party management fees		457		1,373		1,732	2,592
Segmental revenues		5,552		8,398		17,020	17,435
Underwriting deductions
General and administrative expenses		2,929		3,324		10,322	7,557
Share compensation expenses		183		(107)		348	167
Total underwriting deductions		3,086		3,253		10,853	8,655
Segmental (loss) income		2,466		5,145		6,167	8,780
Investment (loss) income from AlphaCat Funds and Sidecars	[4]	(30,090)		6,031		(21,135)	16,059
Finance expenses		32		31		107	914
Tax (benefit) expense		(65)		0		69
Foreign exchange gains (losses)		7		5		7	17
Operating Segments | AlphaCat | AlphaCat sidecars
Underwriting revenues
Gross premiums written		0		(112)		66	(178)
Underwriting deductions
Investment (loss) income from AlphaCat Funds and Sidecars	[4]	201		(72)		68	593
Operating Segments | AlphaCat | AlphaCat ILS funds - Lower Risk
Underwriting revenues
Gross premiums written	[5]	10,979		2,049		117,519	112,241
Underwriting deductions
Investment (loss) income from AlphaCat Funds and Sidecars	[4],[5]	(7,553)		2,321		(4,063)	6,903
Operating Segments | AlphaCat | AlphaCat ILS funds - Higher Risk
Underwriting revenues
Gross premiums written	[5]	16,275		1,797		153,483	140,127
Underwriting deductions
Investment (loss) income from AlphaCat Funds and Sidecars	[4],[5]	(21,816)		2,479		(16,849)	5,607
Operating Segments | AlphaCat | BetaCat ILS funds
Underwriting deductions
Investment (loss) income from AlphaCat Funds and Sidecars	[4]	(922)		1,303		(291)	2,979
Operating Segments | AlphaCat | PaCRe funds
Underwriting deductions
Investment (loss) income from AlphaCat Funds and Sidecars	[4]	0		0		0	(23)
Operating Segments | AlphaCat | AlphaCat direct
Underwriting revenues
Gross premiums written	[6]	(41)		679		26,753	18,476
Operating Segments | AlphaCat And Consolidated Variable Interest Entities
Underwriting revenues
Gross premiums written		27,213		4,413		297,821	270,666
Reinsurance premiums ceded		(2,850)		(1,630)		(9,510)	(6,451)
Net premiums written		24,363		2,783		288,311	264,215
Change in unearned premiums		77,273		62,660		(54,196)	(80,230)
Net premiums earned		101,636		65,443		234,115	183,985
Other insurance related income (loss)		6,083		8,656		17,118	17,722
Segmental revenues		107,719		74,099		251,233	201,707
Underwriting deductions
Losses and loss expenses		570,969		4,361		574,130	27,645
Policy acquisition costs		8,314		7,075		22,380	19,762
General and administrative expenses		7,687		12,255		27,096	26,272
Share compensation expenses		183		(107)		348	167
Total underwriting deductions		587,153		23,584		623,954	73,846
Segmental (loss) income		(479,434)		50,515		(372,721)	127,861
Other items		82	[1]	97	[1]	269	(1,139)
Loss (income) attributable to AlphaCat investors		74,130		(5,564)		54,797	(16,278)
Net (income) attributable to noncontrolling interests		376,366		(37,439)		290,144	(96,163)
Validus share of segmental (loss) income		(27,624)		11,176		(14,968)	24,839
Net investment return	[2]	1,232		3,567		12,543	10,558
Operating Segments | Corporate and investment
Segment Reporting Information [Line Items]
Net Investment Income	[7]	37,091		41,071		111,346	105,843
Underwriting deductions
General and administrative expenses		9,539		18,221		45,563	52,276
Share compensation expenses		3,990		4,048		12,039	12,147
Total underwriting deductions		13,529		22,269		57,602	64,423
Segmental (loss) income		(13,529)		(22,269)		(57,602)	(64,423)
Other items		(18,969)	[1]	(20,995)	[1]	(57,097)	(35,452)
Dividends on preferred shares		(5,627)		(2,252)		(10,033)	(2,252)
Transaction expenses		0		0		(4,427)	0
Finance expenses	[7]	14,449		14,317		42,462	42,637
Tax (benefit) expense		(2,567)		1,830		(7,237)	1,418
Total expenses		31,038		40,668		102,860	110,730
Validus share of segmental (loss) income		7,448		6,992		43,824	89,015
Net realized gains on investments	[7]	903		4,080		280	5,514
Change in net unrealized gains on managed investments	[7]	941		4,652		31,232	81,782
Income (loss) from investment affiliates		1,011		453		15,665	(4,249)
Net investment return	[2]	39,946		50,256		158,523	188,890
Foreign exchange gains (losses)	[7]	1,495		1,067		7,715	(11,628)
Other income		35		(1,529)		303	(773)
Total other items		(1,460)		(2,596)		(11,839)	10,855
Eliminations
Underwriting revenues
Gross premiums written		(6,647)		(1,670)		(23,778)	(21,882)
Reinsurance premiums ceded		6,647		1,670		23,778	21,882
Net premiums written						0	0
Change in unearned premiums						0	0
Net premiums earned						0	0
Other insurance related income (loss)		(3,969)		(8,113)		(14,463)	(16,300)
Segmental revenues		(3,969)		(8,113)		(14,463)	(16,300)
Underwriting deductions
Losses and loss expenses						0	0
Policy acquisition costs		(360)		(60)		(991)	23
General and administrative expenses		(3,950)		(8,065)		(14,311)	(16,421)
Total underwriting deductions		(4,310)		(8,125)		(15,302)	(16,398)
Segmental (loss) income		341		12		839	98
Validus share of segmental (loss) income		$ 341		$ 12		$ 839	(499)
Net investment return	[2]						$ (597)
[1]	Other items includes finance expenses, transaction expenses, dividends on preferred shares, tax benefit (expense), foreign exchange gains (losses), income (loss) from operating affiliate and other income (loss).
[2]	Net investment return includes net investment income, net realized and change in net unrealized gains (losses) on investments and income (loss) from investment affiliates.
[3]	The general and administrative expense ratio includes share compensation expenses.
[4]	The investment (loss) income from the AlphaCat funds and sidecars is based on equity accounting.
[5]	Lower risk AlphaCat ILS funds have a maximum permitted portfolio expected loss of less than 7%, whereas higher risk AlphaCat ILS funds have a maximum permitted portfolio expected loss of greater than 7%. Expected loss represents the average annual loss over the set of simulation scenarios divided by the total limit.
[6]	AlphaCat Direct includes direct investments from third party investors in AlphaCat Re.
[7]	These items exclude the components which are included in Validus’ share of AlphaCat and amounts which are consolidated from VIEs.

Segment information (Gross prem

Segment information (Gross premiums written by geographic location and segment) (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2017		Sep. 30, 2016		Sep. 30, 2017	Sep. 30, 2016
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 523,856		$ 372,418		$ 2,507,615	$ 2,309,251
Percent of gross premiums written	100.00%		100.00%		100.00%	100.10%
United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 253,079		$ 138,303		$ 1,027,853	$ 840,133
Percent of gross premiums written	48.30%		37.10%		41.00%	36.40%
Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 51,122	[1]	$ 43,876	[1]	$ 164,051	$ 178,543
Percent of gross premiums written	9.80%	[1]	11.70%	[1]	6.60%	7.80%
Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 3,255		$ 3,301		$ 14,373	$ 19,361
Percent of gross premiums written	0.60%		0.90%		0.60%	0.80%
Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 10,327		$ 9,533		$ 58,284	$ 58,581
Percent of gross premiums written	2.00%		2.60%		2.20%	2.50%
Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 39,702		$ 41,416		$ 105,658	$ 106,857
Percent of gross premiums written	7.60%		11.10%		4.20%	4.60%
Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 1,601		$ 971		$ 51,092	$ 48,668
Percent of gross premiums written	0.30%		0.30%		2.00%	2.10%
Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 2,296		$ 2,122		$ 9,495	$ 9,317
Percent of gross premiums written	0.40%		0.60%		0.40%	0.40%
Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 22,982	[2]	$ 21,592	[2]	$ 86,627	$ 96,487
Percent of gross premiums written	4.40%	[2]	5.80%	[2]	3.50%	4.20%
Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 131,285		$ 122,811		$ 489,580	$ 517,814
Percent of gross premiums written	25.10%		33.00%		19.50%	22.40%
Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 54,919	[1]	$ 37,204	[1]	$ 416,418	$ 405,747
Percent of gross premiums written	10.50%	[1]	10.00%	[1]	16.60%	17.60%
Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 84,573	[3]	$ 74,100	[3]	$ 573,764	$ 545,557
Percent of gross premiums written	16.10%	[3]	19.90%	[3]	22.90%	23.60%
Operating Segments | Validus Re
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 153,890		$ 94,741		$ 1,071,409	$ 1,072,219
Operating Segments | Validus Re | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	59,838		31,345		374,018	455,826
Operating Segments | Validus Re | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	7,198	[1]	4,145	[1]	45,803	51,384
Operating Segments | Validus Re | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	(450)		57		3,745	6,906
Operating Segments | Validus Re | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	4,744		4,536		35,108	30,270
Operating Segments | Validus Re | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	19,430		17,036		40,646	36,610
Operating Segments | Validus Re | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	436		(33)		40,902	39,892
Operating Segments | Validus Re | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	24		149		4,894	3,646
Operating Segments | Validus Re | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	1,447	[2]	2,360	[2]	20,229	22,307
Operating Segments | Validus Re | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	32,829		28,250		191,327	191,015
Operating Segments | Validus Re | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	33,724	[1]	22,399	[1]	189,669	169,737
Operating Segments | Validus Re | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	27,499	[3]	12,747	[3]	316,395	255,641
Operating Segments | Talbot Segment
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	192,883		189,674		702,535	752,058
Operating Segments | Talbot Segment | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	24,584		19,937		88,139	85,182
Operating Segments | Talbot Segment | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	43,136	[1]	40,058	[1]	110,094	105,590
Operating Segments | Talbot Segment | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	3,696		3,238		8,726	7,613
Operating Segments | Talbot Segment | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	5,372		4,957		22,944	25,673
Operating Segments | Talbot Segment | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	20,726		25,173		69,703	76,577
Operating Segments | Talbot Segment | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	1,165		997		6,371	5,579
Operating Segments | Talbot Segment | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	1,820		2,015		4,068	5,577
Operating Segments | Talbot Segment | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	21,478	[2]	19,166	[2]	67,918	76,456
Operating Segments | Talbot Segment | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	97,393		95,604		289,824	303,065
Operating Segments | Talbot Segment | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	16,293	[1]	12,771	[1]	74,385	75,423
Operating Segments | Talbot Segment | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	54,613	[3]	61,362	[3]	250,187	288,388
Operating Segments | Western World
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	156,517		85,260		459,628	236,190
Operating Segments | Western World | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	156,517		85,260		459,628	236,190
Operating Segments | Western World | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0	[1]	0	[1]	0	0
Operating Segments | Western World | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0		0		0	0
Operating Segments | Western World | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0		0		0	0
Operating Segments | Western World | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0		0		0	0
Operating Segments | Western World | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0		0		0	0
Operating Segments | Western World | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0		0		0	0
Operating Segments | Western World | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0	[2]	0	[2]	0	0
Operating Segments | Western World | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0		0		0	0
Operating Segments | Western World | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0	[1]	0	[1]	0	0
Operating Segments | Western World | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0	[3]	0	[3]	0	0
Operating Segments | AlphaCat
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	27,213		4,413		297,821	270,666
Operating Segments | AlphaCat | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	18,440		1,837		116,691	64,566
Operating Segments | AlphaCat | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	712	[1]	(288)	[1]	8,617	22,219
Operating Segments | AlphaCat | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0		0		2,003	4,949
Operating Segments | AlphaCat | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	149		0		600	3,306
Operating Segments | AlphaCat | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0		0		46	0
Operating Segments | AlphaCat | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0		0		3,855	3,221
Operating Segments | AlphaCat | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	458		0		588	223
Operating Segments | AlphaCat | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0	[2]	0	[2]	0	0
Operating Segments | AlphaCat | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	1,319		(288)		15,709	33,918
Operating Segments | AlphaCat | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	4,993	[1]	2,872	[1]	158,239	170,639
Operating Segments | AlphaCat | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	2,461	[3]	(8)	[3]	7,182	1,543
Operating Segments | AlphaCat And Consolidated Variable Interest Entities
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	27,213		4,413		297,821	270,666
Eliminations
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	(6,647)		(1,670)		(23,778)	(21,882)
Eliminations | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	(6,300)		(76)		(10,623)	(1,631)
Eliminations | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	76	[1]	(39)	[1]	(463)	(650)
Eliminations | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	9		6		(101)	(107)
Eliminations | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	62		40		(368)	(668)
Eliminations | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	(454)		(793)		(4,737)	(6,330)
Eliminations | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0		7		(36)	(24)
Eliminations | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	(6)		(42)		(55)	(129)
Eliminations | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	57	[2]	66	[2]	(1,520)	(2,276)
Eliminations | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	(256)		(755)		(7,280)	(10,184)
Eliminations | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	(91)	[1]	(838)	[1]	(5,875)	(10,052)
Eliminations | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$ 0	[3]	$ (1)	[3]	$ 0	$ (15)
[1]	Represents risks in two or more geographic zones.
[2]	Represents risks in one geographic zone.
[3]	The Other locations non-specific category refers to business for which an analysis of exposure by geographic zone is not applicable since these exposures can span multiple geographic areas and, in some instances, are not fixed locations.

Subsequent events - Narrative (

Subsequent events - Narrative (Details) - $ / shares	Nov. 01, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2017	Sep. 30, 2016
Subsequent Event [Line Items]
Cash dividends declared per share - common shares		$ 0.38	$ 0.38	$ 0.38	$ 0.35	$ 0.35	$ 0.35	$ 1.14	$ 1.05
Series A depositary share equivalent
Subsequent Event [Line Items]
Cash dividends declared per share - preferred shares		0.3671875	$ 0.3671875	$ 0.3671875	$ 0.3753472
Series B depositary share equivalent
Subsequent Event [Line Items]
Cash dividends declared per share - preferred shares		$ 0.3423611
Subsequent Event
Subsequent Event [Line Items]
Cash dividends declared per share - common shares	$ 0.38
Subsequent Event | Series A depositary share equivalent
Subsequent Event [Line Items]
Cash dividends declared per share - preferred shares	0.3671875
Subsequent Event | Series B depositary share equivalent
Subsequent Event [Line Items]
Cash dividends declared per share - preferred shares	$ 0.3625000