Validus 10-Q 5 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	May 03, 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	Mar. 31, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
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		79,140,542

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets
Fixed maturity investments trading, at fair value (amortized cost: 2017—$5,391,103; 2016—$5,584,599)	$ 5,365,216	$ 5,543,030
Short-term investments trading, at fair value (amortized cost: 2017—$2,785,232; 2016—$2,796,358)	2,785,226	2,796,170
Other investments, at fair value (cost: 2017—$415,679; 2016—$380,130)	443,004	405,712
Investments in investment affiliates, equity method (cost: 2017—$73,918; 2016—$84,840)	94,697	100,431
Cash and cash equivalents	623,937	419,976
Restricted cash	92,547	70,956
Total investments, cash and cash equivalents	9,404,627	9,336,275
Premiums receivable	1,214,745	725,390
Deferred acquisition costs	292,180	209,227
Prepaid reinsurance premiums	199,046	77,996
Securities lending collateral	10,386	9,779
Loss reserves recoverable	451,856	430,421
Paid losses recoverable	37,837	35,247
Income taxes recoverable	6,757	4,870
Deferred tax asset	45,995	43,529
Receivable for investments sold	9,302	3,901
Intangible assets	114,176	115,592
Goodwill	196,758	196,758
Accrued investment income	25,962	26,488
Other assets	127,494	134,282
Total assets	12,137,121	11,349,755
Liabilities
Reserve for losses and loss expenses	3,052,745	2,995,195
Unearned premiums	1,612,474	1,076,049
Reinsurance balances payable	118,119	54,781
Securities lending payable	10,852	10,245
Deferred tax liability	3,818	3,331
Payable for investments purchased	38,486	29,447
Accounts payable and accrued expenses	171,134	587,648
Notes payable to AlphaCat investors	446,576	278,202
Senior notes payable	245,412	245,362
Debentures payable	537,402	537,226
Total liabilities	6,237,018	5,817,486
Commitments and contingent liabilities
Redeemable noncontrolling interest	1,657,630	1,528,001
Shareholders' equity
Preferred shares (Issued and Outstanding: 2017—6,000; 2016—6,000)	150,000	150,000
Common shares (Issued: 2017—161,285,411; 2016—161,279,976; Outstanding: 2017—79,137,590; 2016—79,132,252)	28,225	28,224
Treasury shares (2017—82,147,821; 2016—82,147,724)	(14,376)	(14,376)
Additional paid-in capital	830,346	821,023
Accumulated other comprehensive loss	(22,453)	(23,216)
Retained earnings	2,940,134	2,876,636
Total shareholders' equity available to Validus	3,911,876	3,838,291
Noncontrolling interest	330,597	165,977
Total shareholders' equity	4,242,473	4,004,268
Total liabilities, noncontrolling interests and shareholders’ equity	$ 12,137,121	$ 11,349,755

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets
Fixed maturities, at amortized cost or cost	$ 5,391,103	$ 5,584,599
Short-term investments, at amortized cost or cost	2,785,232	2,796,358
Other investments, at amortized cost or cost	415,679	380,130
Investments in and advance to affiliates, subsidiaries, associates, and joint ventures, at cost	$ 73,918	$ 84,840
Preferred shares - Shareholders' Equity
Preferred shares, shares issued	6,000	6,000
Preferred shares, shares outstanding	6,000	6,000
Common Shares - Shareholders' Equity
Common shares, shares issued	161,285,411	161,279,976
Common shares, shares outstanding	79,137,590	79,132,252
Treasury stock, common shares	82,147,724	82,147,724

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenues
Gross premiums written	$ 1,190,857	$ 1,172,791
Reinsurance premiums ceded	(200,106)	(167,835)
Net premiums written	990,751	1,004,956
Change in unearned premiums	(415,375)	(433,688)
Net premiums earned	575,376	571,268
Net investment income	40,214	29,461
Net realized losses on investments	(1,164)	(584)
Change in net unrealized gains on investments	13,348	47,444
Income (loss) from investment affiliates	5,188	(4,113)
Other insurance related income and other income	1,330	1,413
Foreign exchange gains	1,569	6,245
Total revenues	635,861	651,134
Expenses
Losses and loss expenses	269,585	224,447
Policy acquisition costs	111,628	107,193
General and administrative expenses	87,924	86,208
Share compensation expenses	9,491	11,237
Finance expenses	13,943	15,203
Total expenses	492,571	444,288
Income before taxes, loss from operating affiliate and (income) attributable to AlphaCat investors	143,290	206,846
Tax benefit	3,549	2,118
Loss from operating affiliate	0	(23)
(Income) attributable to AlphaCat investors	(7,503)	(4,600)
Net income	139,336	204,341
Net (income) attributable to noncontrolling interest	(42,572)	(37,531)
Net income available to Validus	96,764	166,810
Dividends on preferred shares	(2,203)	0
Net income available to Validus common shareholders	94,561	166,810
Comprehensive income
Net income	139,336	204,341
Other comprehensive income (loss)
Change in foreign currency translation adjustments	597	(2,028)
Change in minimum pension liability, net of tax	68	(83)
Change in fair value of cash flow hedge	98	(758)
Other comprehensive income (loss), net of tax	763	(2,869)
Comprehensive (income) attributable to noncontrolling interests	(42,572)	(37,531)
Comprehensive income available to Validus	$ 97,527	$ 163,941
Earnings per common share
Basic earnings per share available to common shareholders	$ 1.19	$ 2.01
Earnings per diluted share available to Validus common shareholders	1.17	1.98
Cash dividends declared per share	$ 0.38	$ 0.35
Weighted average number of common shares and common share equivalents outstanding:
Basic (in shares)	79,133,671	82,821,261
Diluted (in shares)	80,739,142	84,198,315

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
Total shareholders' equity						$ (12,569)
Balance - Beginning of period at Dec. 31, 2015		$ 0	$ 28,100	$ (13,592)	$ 1,002,980	(12,569)	$ 2,634,056
Common shares issued, net			2		398
Repurchase of common shares				(238)	(60,130)
Share compensation expenses					11,237
Other comprehensive (loss) income	$ (2,869)					(2,869)
Net income	204,341						204,341
Net (income) attributable to noncontrolling interest	(37,531)						(37,531)
Dividends on preferred shares							0
Dividends on common shares							(29,759)
Balance - End of period at Mar. 31, 2016	3,724,426	0	28,102	(13,830)	954,485	(15,438)	2,771,107
Noncontrolling interest at Mar. 31, 2016	157,223
Total shareholders' equity	3,881,649					(15,438)
Total shareholders' equity	4,004,268					(23,216)
Balance - Beginning of period at Dec. 31, 2016	3,838,291	150,000	28,224	(14,376)	821,023	(23,216)	2,876,636
Common shares issued, net			1		(168)
Repurchase of common shares				0	0
Share compensation expenses					9,491
Other comprehensive (loss) income	763					763
Net income	139,336						139,336
Net (income) attributable to noncontrolling interest	(42,572)						(42,572)
Dividends on preferred shares							(2,203)
Dividends on common shares							(31,063)
Balance - End of period at Mar. 31, 2017	3,911,876	$ 150,000	$ 28,225	$ (14,376)	$ 830,346	(22,453)	$ 2,940,134
Noncontrolling interest at Mar. 31, 2017	330,597
Total shareholders' equity	$ 4,242,473					$ (22,453)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows provided by (used in) operating activities
Net income	$ 139,336	$ 204,341
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Share compensation expenses	9,491	11,237
Amortization of discount on senior notes	27	27
(Income) loss from investment affiliates	(5,188)	4,113
Net realized and change in net unrealized losses on investments	(12,184)	(46,860)
Amortization of intangible assets	1,416	1,416
Loss from operating affiliate	0	23
Foreign exchange gains included in net income	(4,938)	(6,457)
Amortization of premium on fixed maturities	3,536	4,538
Change in:
Premiums receivable	(488,653)	(519,713)
Deferred acquisition costs	(82,953)	(81,673)
Prepaid reinsurance premiums	(121,050)	(103,263)
Loss reserves recoverable	(20,743)	(20,966)
Paid losses recoverable	(2,619)	(1,807)
Reserve for losses and loss expenses	53,436	(10,740)
Unearned premiums	536,425	536,951
Reinsurance balances payable	63,070	21,658
Other operational balance sheet items, net	(50,610)	(26,871)
Net cash provided by (used in) operating activities	17,799	(34,046)
Cash flows provided by (used in) investing activities
Proceeds on sales of fixed maturity investments	743,631	734,892
Proceeds on maturities of fixed maturity investments	123,269	79,925
Purchases of fixed maturity investments	(676,349)	(726,233)
Proceeds on sales (purchases) of short-term investments, net	11,030	(166,362)
Purchases of other investments, net	(34,295)	(3,690)
Increase in securities lending collateral	(607)	(4,858)
Distributions from (investments) in investment affiliates, net	10,922	(575)
Increase in restricted cash	(21,591)	(35,125)
Net cash provided by (used in) investing activities	156,010	(122,026)
Cash flows provided by (used in) financing activities
Net proceeds on issuance of notes payable to AlphaCat investors	73,048	247,400
(Redemption) issuance of common shares, net	(167)	400
Purchases of common shares under share repurchase program	0	(60,368)
Dividends paid on preferred shares	(2,203)	0
Dividends paid on common shares	(30,092)	(28,637)
Increase in securities lending payable	607	4,858
Third party investment in redeemable noncontrolling interests	103,699	268,750
Third party redemption of redeemable noncontrolling interests	(68,296)	(10,800)
Third party investment in noncontrolling interests	154,980	112,325
Third party distributions of noncontrolling interests	(62,770)	(118,722)
Third party subscriptions deployed on AlphaCat Funds and Sidecars	(144,452)	(412,036)
Net cash provided by financing activities	24,354	3,170
Effect of foreign currency rate changes on cash and cash equivalents	5,798	(433)
Net increase (decrease) in cash and cash equivalents	203,961	(153,335)
Cash and cash equivalents - beginning of period	419,976	723,109
Cash and cash equivalents - end of period	623,937	569,774
Supplemental disclosure of cash flow information:
Taxes paid during the period	16	2,117
Interest paid during the period	$ 19,073	$ 19,303

Basis of preparation and consol

Basis of preparation and consolidation	3 Months Ended
	Mar. 31, 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	3 Months Ended
	Mar. 31, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent accounting pronouncements	Recent accounting pronouncements (a) Recently issued accounting standards adopted during the period In March 2016, the FASB issued Accounting Standard Update (“ASU”) 2016-07, “Investments-Equity Method and Joint Ventures (Topic 323) - Simplifying the Transition to the Equity Method of Accounting.” The amendments in this ASU eliminate the requirement to retroactively adopt the equity method of accounting when an investment becomes qualified for the equity method of accounting as a result of an increase in the level of ownership interest or degree of influence. The amendments in this ASU became effective for the Company on January 1, 2017. Adoption of this guidance did not have a material impact on the Company’s Consolidated Financial Statements. In March 2016, the FASB issued ASU 2016-09, “Compensation-Stock Compensation (Topic 718) - Improvements to Employee Share-Based Payment Accounting.” The amendments in this ASU simplify several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. The amendments in this ASU became effective for the Company on January 1, 2017. Adoption of this guidance did not have a material impact on the Company’s Consolidated Financial Statements. In October 2016, the FASB issued ASU 2016-17, “Consolidation (Topic 810) - Interests Held Through Related Parties That Are Under Common Control.” The amendments in this ASU do not change the characteristics of a primary beneficiary in current U.S. GAAP. Rather, the ASU requires that a reporting entity, in determining whether it satisfies the second characteristic of a primary beneficiary, include all of its direct variable interests in a VIE and, on a proportionate basis, its indirect variable interests in a VIE held through related parties, including related parties that are under common control with the reporting entity. The amendments in this ASU became effective for the Company on January 1, 2017. Adoption of this guidance did not have a material impact on the Company’s Consolidated Financial Statements. (b) Recently issued accounting standards not yet adopted In March 2017, the FASB issued ASU 2017-08, “Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20).” The amendments in this ASU shorten the amortization period for certain callable debt securities held at a premium. Specifically, the amendments require the premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. The amendments in this ASU are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, including adoption in an interim period. The Company has evaluated the impact of this guidance and it will not have a material impact on the Company’s Consolidated Financial Statements. The Company plans to adopt this guidance on January 1, 2019.

Investments

Investments	3 Months Ended
	Mar. 31, 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 5 , “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 March 31, 2017 and December 31, 2016 were as follows: March 31, 2017 December 31, 2016 Amortized Amortized Fair Value Managed investments U.S. government and government agency $ 721,859 $ 718,025 $ 809,392 $ 804,126 Non-U.S. government and government agency 261,860 258,463 245,651 240,791 U.S. states, municipalities and political subdivisions 228,818 229,129 271,742 271,830 Agency residential mortgage-backed securities 658,476 653,395 684,490 679,595 Non-agency residential mortgage-backed securities 19,678 19,382 15,858 15,477 U.S. corporate 1,484,897 1,486,882 1,540,036 1,534,508 Non-U.S. corporate 403,471 397,989 418,520 410,227 Bank loans 573,263 567,012 579,121 570,399 Asset-backed securities 515,219 514,690 528,563 526,814 Commercial mortgage-backed securities 321,562 318,288 333,740 330,932 Total fixed maturities 5,189,103 5,163,255 5,427,113 5,384,699 Short-term investments 232,961 232,955 228,574 228,386 Other investments Fund of hedge funds 1,457 996 1,457 955 Hedge funds 11,292 17,624 11,292 17,381 Private equity investments 78,871 95,927 66,383 82,627 Fixed income investment funds 267,425 269,113 247,967 249,275 Overseas deposits 53,709 53,709 50,106 50,106 Mutual funds 2,925 5,635 2,925 5,368 Total other investments 415,679 443,004 380,130 405,712 Investments in investment affiliates (a) 73,918 94,697 84,840 100,431 Total managed investments $ 5,911,661 $ 5,933,911 $ 6,120,657 $ 6,119,228 Non-managed investments Catastrophe bonds $ 202,000 $ 201,961 $ 157,486 $ 158,331 Short-term investments 2,552,271 2,552,271 2,567,784 2,567,784 Total non-managed investments 2,754,271 2,754,232 2,725,270 2,726,115 Total investments $ 8,665,932 $ 8,688,143 $ 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 March 31, 2017 and December 31, 2016 . March 31, 2017 December 31, 2016 Fair Value % of Total Fair Value % of Total Managed fixed maturities AAA $ 2,265,668 42.2 % $ 2,405,597 43.4 % AA 533,767 9.9 % 538,289 9.7 % A 1,000,955 18.7 % 1,081,949 19.5 % BBB 730,325 13.6 % 740,861 13.4 % Total investment grade managed fixed maturities 4,530,715 84.4 % 4,766,696 86.0 % BB 236,477 4.4 % 213,568 3.9 % B 167,170 3.1 % 177,737 3.2 % CCC 11,818 0.2 % 13,371 0.2 % NR 217,075 4.1 % 213,327 3.8 % Total non-investment grade fixed maturities 632,540 11.8 % 618,003 11.1 % Total managed fixed maturities $ 5,163,255 96.2 % $ 5,384,699 97.1 % Non-managed fixed maturities BB 25,275 0.5 % 29,731 0.6 % B 4,509 0.1 % 4,524 0.1 % NR 172,177 3.2 % 124,076 2.2 % Total non-managed fixed maturities 201,961 3.8 % 158,331 2.9 % Total fixed maturities $ 5,365,216 100.0 % $ 5,543,030 100.0 % The amortized cost and fair value amounts for the Company’s fixed maturity investments held at March 31, 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. March 31, 2017 December 31, 2016 Amortized Cost Fair Value Amortized Cost Fair Value Managed fixed maturities Due in one year or less $ 438,198 $ 433,710 $ 350,733 $ 346,161 Due after one year through five years 2,703,019 2,691,398 2,954,856 2,933,146 Due after five years through ten years 443,791 443,221 430,365 426,647 Due after ten years 89,160 89,171 128,508 125,927 3,674,168 3,657,500 3,864,462 3,831,881 Asset-backed and mortgage-backed securities 1,514,935 1,505,755 1,562,651 1,552,818 Total managed fixed maturities $ 5,189,103 $ 5,163,255 $ 5,427,113 $ 5,384,699 Non-managed catastrophe bonds Due in one year or less $ 43,052 $ 41,242 $ 43,664 $ 45,418 Due after one year through five years 157,698 159,463 112,572 111,656 Due after five years through ten years 1,250 1,256 1,250 1,257 Due after ten years — — — — Total non-managed fixed maturities 202,000 201,961 157,486 158,331 Total fixed maturities $ 5,391,103 $ 5,365,216 $ 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 March 31, 2017 and December 31, 2016 : March 31, 2017 Fair Value Investments with redemption restrictions Investments without redemption restrictions Redemption frequency (a) Redemption notice period (a) Fund of hedge funds $ 996 $ 996 $ — Hedge funds 17,624 17,624 — Private equity investments 95,927 95,927 — Fixed income investment funds 269,113 229,790 39,323 Daily Daily to 2 days Overseas deposits 53,709 53,709 — Mutual funds 5,635 — 5,635 Daily Daily Total other investments $ 443,004 $ 398,046 $ 44,958 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 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 $188,682 ( December 31, 2016 : $184,749 ), has a lock-up period of approximately two years as at March 31, 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 14 , “ Commitments and contingencies ,” for further details. As at March 31, 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 March 31, 2017 were investments in Aquiline Financial Services Fund II L.P. (“Aquiline II”), Aquiline Financial Services Fund III L.P. (the “Aquiline III”) and Aquiline Technology Growth Fund L.P. (“Aquiline Tech”). 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 March 31, 2017 , the unfunded investment commitment to Aquiline Tech was $20,000 . 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 March 31, 2017 , the Company’s total unfunded investment commitment to Aquiline II and III was $2,830 and $62,031 , respectively ( December 31, 2016 : $2,040 and $62,031 ). The following table presents a reconciliation of the Company’s beginning and ending investments in investment affiliates for the three months ended March 31, 2017 and 2016 : Three Months Ended March 31, 2017 2016 Investments in investment affiliates, beginning of period $ 100,431 $ 87,673 Net capital (distributions) contributions (10,922 ) 575 Income (loss) from investment affiliates 5,188 (4,113 ) Investments in investment affiliates, end of period $ 94,697 $ 84,135 The following table presents the Company’s investments in investment affiliates as at March 31, 2017 and December 31, 2016 : March 31, 2017 Investment at cost Voting ownership % Equity ownership % Carrying value Aquiline II $ 35,949 — % 8.1 % $ 54,524 Aquiline III 37,969 — % 9.0 % 40,173 Aquiline Tech — — % 16.4 % — Total investments in investment affiliates $ 73,918 $ 94,697 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 March 31, 2017 2016 Managed investments Fixed maturities and short-term investments $ 31,671 $ 28,017 Other investments 6,870 872 Cash and cash equivalents and restricted cash 610 865 Securities lending income 13 5 Total gross investment income 39,164 29,759 Investment expenses (2,972 ) (1,836 ) Total managed net investment income $ 36,192 $ 27,923 Non managed investments Fixed maturities and short-term investments $ 3,060 $ 1,295 Restricted cash, cash and cash equivalents 962 243 Total non-managed net investment income 4,022 1,538 Total net investment income $ 40,214 $ 29,461 Net investment income from other investments includes distributed and undistributed net income from certain fixed income investment funds. (e) Net realized and change in net unrealized gains on investments The following table sets forth an analysis of net realized losses and the change in net unrealized gains on investments: Three Months Ended March 31, 2017 2016 Managed fixed maturities, short-term and other investments Gross realized gains $ 2,690 $ 3,217 Gross realized (losses) (5,582 ) (4,303 ) Net realized losses on investments (2,892 ) (1,086 ) Change in net unrealized gains on investments 14,349 47,078 Total net realized and change in net unrealized gains on managed investments $ 11,457 $ 45,992 Non-managed fixed maturities, short-term and other investments Gross realized gains $ 1,728 $ 511 Gross realized (losses) — (9 ) Net realized gains on investments 1,728 502 Change in net unrealized (losses) gains on investments (1,001 ) 366 Total net realized and change in net unrealized gains on non-managed investments 727 868 Total net realized and change in net unrealized gains on total investments $ 12,184 $ 46,860 (f) Pledged cash and investments As at March 31, 2017 , the Company had $5,173,735 ( 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, $5,105,855 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 $412,176 ( December 31, 2016 : $442,184 ). For further details on the credit facilities, please refer to Note 12 , “ Debt and financing arrangements .”

Fair value measurements

Fair value measurements	3 Months Ended
	Mar. 31, 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 March 31, 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 $ — $ 718,025 $ — $ — $ 718,025 Non-U.S. government and government agency — 258,463 — — 258,463 U.S. states, municipalities and political subdivisions — 229,129 — — 229,129 Agency residential mortgage-backed securities — 653,395 — — 653,395 Non-agency residential mortgage-backed securities — 19,382 — — 19,382 U.S. corporate — 1,486,882 — — 1,486,882 Non-U.S. corporate — 397,989 — — 397,989 Bank loans — 330,318 236,694 — 567,012 Asset-backed securities — 490,808 23,882 — 514,690 Commercial mortgage-backed securities — 318,288 — — 318,288 Total fixed maturities — 4,902,679 260,576 — 5,163,255 Short-term investments 214,859 18,096 — — 232,955 Other investments Fund of hedge funds — — — 996 996 Hedge funds — — — 17,624 17,624 Private equity investments — — — 95,927 95,927 Fixed income investment funds — 39,323 12,560 217,230 269,113 Overseas deposits — — — 53,709 53,709 Mutual funds — 5,635 — — 5,635 Total other investments — 44,958 12,560 385,486 443,004 Investments in investment affiliates (b) — — — — 94,697 Total managed investments $ 214,859 $ 4,965,733 $ 273,136 $ 385,486 $ 5,933,911 Non-managed investments Catastrophe bonds $ — $ 129,285 $ 72,676 $ — $ 201,961 Short-term investments 2,552,271 — — — 2,552,271 Total non-managed investments 2,552,271 129,285 72,676 — 2,754,232 Total investments $ 2,767,130 $ 5,095,018 $ 345,812 $ 385,486 $ 8,688,143 (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 March 31, 2017 , managed Level 3 investments totaled $273,136 (December 31, 2016 : $282,595 ), representing 4.6% (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 ( “ TBA ” ) 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 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 The fund of hedge funds includes a side pocket. While a redemption request has been submitted, the timing of receipt of proceeds on the side pocket is unknown. The fund’s administrator provides a monthly reported NAV with a three month delay in its valuation. The fund manager has 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 compares the fund administrator’s NAV to the fund manager’s estimated NAV that incorporates relevant valuation sources on a timely basis. Material variances are recorded in the current reporting period while immaterial variances are recorded in the following reporting period. The fair value of these investments are measured using the NAV practical expedient and therefore have not been categorized within the fair value hierarchy. Hedge funds The hedge fund investment was assumed by the Company in the acquisition of Flagstone Reinsurance Holdings, S.A. (“Flagstone”) (the “Flagstone hedge fund”). The Flagstone 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 months ended March 31, 2017 and 2016 : Three Months Ended March 31, 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 23,176 61,091 — — 84,267 Settlements (33,110 ) (38,780 ) 392 — (71,498 ) Net realized gains — 3,134 — — 3,134 Change in net unrealized gains (losses) 132 (1,144 ) — (49 ) (1,061 ) Level 3 investments, end of period $ 236,694 $ 72,676 $ 12,560 $ 23,882 $ 345,812 Three Months Ended March 31, 2016 Bank Loans Catastrophe Bonds Total Level 3 investments, beginning of period $ 232,337 $ 13,500 $ 245,837 Purchases 42,103 23,272 65,375 Sales (2,389 ) — (2,389 ) Settlements (16,249 ) (125 ) (16,374 ) Change in net unrealized (losses) gains (791 ) 458 (333 ) Level 3 investments, end of period $ 255,011 $ 37,105 $ 292,116 There have not been any transfers into or out of Level 3 during the three months ended March 31, 2017 or 2016 , respectively. (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 March 31, 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	3 Months Ended
	Mar. 31, 2017
Variable Interest Entities Disclosure [Abstract]
Variable Interest Entity Disclosure [Text Block]	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”). The AlphaCat ILS funds are VIEs and are consolidated by the Company as the primary beneficiary. 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 14 , “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. As both the master and feeder funds are consolidated by the Company, any notes issued by the master funds to the feeder funds are eliminated on consolidation and only variable funding notes issued by AlphaCat Re to direct third party investors 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 2016 and 2017, 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 and earn an interest rate of 8.0% 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) loss 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 table presents a reconciliation of the beginning and ending notes payable to AlphaCat investors as at March 31, 2017 and December 31, 2016 : Three Months Ended March 31, 2017 Variable Funding Notes Structured Notes Total Notes payable to AlphaCat investors, beginning of period $ 278,202 $ — $ 278,202 Issuance of notes payable to AlphaCat investors 274,010 103,320 377,330 Redemption of notes payable to AlphaCat investors (208,956 ) — (208,956 ) Foreign exchange gains — — — Notes payable to AlphaCat investors, end of period $ 343,256 $ 103,320 $ 446,576 Year Ended December 31, 2016 Variable Funding Notes Structured Notes Total Notes payable to AlphaCat investors, beginning of year $ 75,493 $ — $ 75,493 Issuance of notes payable to AlphaCat investors 311,711 94,326 406,037 Redemption of notes payable to AlphaCat investors (109,712 ) (94,326 ) (204,038 ) Foreign exchange gains 710 — 710 Notes payable to AlphaCat investors, end of year $ 278,202 $ — $ 278,202 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 income attributable to AlphaCat investors for the three months ended March 31, 2017 was $7,503 ( 2016 : $4,600 ), with $9,510 included in accounts payable and accrued expenses as at March 31, 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 March 31, 2017 and December 31, 2016 : March 31, 2017 December 31, 2016 Total Assets Total Liabilities Total Assets Total Liabilities AlphaCat sidecars $ 28,998 $ 3,196 $ 40,041 $ 3,206 AlphaCat ILS funds - Lower Risk (a) 1,430,039 41,699 1,498,276 42,457 AlphaCat ILS funds - Higher Risk (a) 866,386 143,629 972,633 381,332 AlphaCat Re and AlphaCat Master Fund 2,541,415 2,541,245 2,510,415 2,510,245 BetaCat ILS funds 88,656 219 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 3 , “ 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	3 Months Ended
	Mar. 31, 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 months ended March 31, 2017 and 2016 : Redeemable noncontrolling interests Noncontrolling interests Total Three Months Ended March 31, Three Months Ended March 31, Three Months Ended March 31, 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 103,699 268,750 154,980 112,325 258,679 381,075 Income attributable to noncontrolling interests 25,930 28,573 16,642 8,958 42,572 37,531 Redemption of shares / distributions — — (7,002 ) (118,722 ) (7,002 ) (118,722 ) Balance, end of period $ 1,657,630 $ 1,409,037 $ 330,597 $ 157,223 $ 1,988,227 $ 1,566,260 As at March 31, 2017 , redemptions of $3,234 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	3 Months Ended
	Mar. 31, 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 and interest rate exposures. (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 March 31, 2017 and December 31, 2016 : March 31, 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 $ 152,683 $ 1,475 $ 1,517 $ 181,375 $ 2,351 $ 3,421 (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 contracts that were not designated as hedging instruments for accounting purposes during the three months ended March 31, 2017 and 2016 : Derivatives not designated as hedging instruments Classification of gains (losses) recognized in earnings Three Months Ended March 31, 2017 2016 Foreign currency forward contracts Foreign exchange gains (losses) $ 453 $ (2,013 ) Foreign currency forward contracts Other (loss) income (105 ) 36 (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 March 31, 2017 and December 31, 2016 : March 31, 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 $ 552,563 $ 20 $ 1,314 $ 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 months ended March 31, 2017 and 2016 : Three Months Ended March 31, Interest rate swap contracts 2017 2016 Amount of effective portion recognized in other comprehensive income $ 2,160 $ 3,656 Amount of effective portion subsequently reclassified to earnings $ (2,257 ) $ (2,898 ) Amount of ineffective portion excluded from effectiveness testing $ 97 $ (758 ) 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 4 , “ 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 March 31, 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	3 Months Ended
	Mar. 31, 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 March 31, 2017 and December 31, 2016 : March 31, 2017 December 31, 2016 Case reserves $ 1,234,156 $ 1,237,772 IBNR 1,818,589 1,757,423 Total reserve for losses and loss expenses $ 3,052,745 $ 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 months ended March 31, 2017 and 2016 : Three Months Ended March 31, 2017 2016 Reserve for losses and loss expenses, beginning of period $ 2,995,195 $ 2,996,567 Loss reserves recoverable (430,421 ) (350,586 ) Net reserves for losses and loss expenses, beginning of period 2,564,774 2,645,981 Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in: Current year 330,816 278,186 Prior years (61,231 ) (53,739 ) Total net incurred losses and loss expenses 269,585 224,447 Less net losses and loss expenses paid in respect of losses occurring in: Current year (7,698 ) (15,774 ) Prior years (238,089 ) (253,303 ) Total net paid losses (245,787 ) (269,077 ) Foreign exchange loss 12,317 8,260 Net reserve for losses and loss expenses, end of period 2,600,889 2,609,611 Loss reserves recoverable 451,856 370,689 Reserve for losses and loss expenses, end of period $ 3,052,745 $ 2,980,300 Incurred losses and loss expenses comprise: Three Months Ended March 31, 2017 2016 Gross losses and loss expenses $ 346,795 $ 269,853 Reinsurance recoverable (77,210 ) (45,406 ) Net incurred losses and loss expenses $ 269,585 $ 224,447 The net favorable development on prior years by segment and line of business for the three months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 2017 Property Marine Specialty Liability Total Validus Re $ (3,571 ) $ (15,429 ) $ (9,780 ) $ — $ (28,780 ) Talbot (6,334 ) (15,996 ) (6,484 ) — (28,814 ) Western World (2,823 ) — — 2,604 (219 ) AlphaCat (4,395 ) — 977 — (3,418 ) Net (favorable) adverse development $ (17,123 ) $ (31,425 ) $ (15,287 ) $ 2,604 $ (61,231 ) The favorable development on prior years was primarily due to favorable development on attritional losses. Three Months Ended March 31, 2016 Property Marine Specialty Liability Total Validus Re $ (22,832 ) $ 3,555 $ (6,407 ) $ — $ (25,684 ) Talbot (18,446 ) 2,964 (7,238 ) — (22,720 ) Western World (441 ) — — (3,985 ) (4,426 ) AlphaCat (181 ) — (728 ) — (909 ) Net favorable development $ (41,900 ) $ 6,519 $ (14,373 ) $ (3,985 ) $ (53,739 ) The Validus Re and Talbot segments experienced favorable development on prior years in the property and specialty lines primarily due to favorable development on attritional losses; whereas, the unfavorable development in the marine lines was primarily driven by adverse development on events, which included unfavorable development on an individual marine policy that incepted during the second half of 2015. This adverse development was partially offset by favorable development on attritional losses. The Western World segment experienced favorable development on prior years primarily due to favorable development on attritional losses.

Reinsurance

Reinsurance	3 Months Ended
	Mar. 31, 2017
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance The Company’s reinsurance balances recoverable at March 31, 2017 and December 31, 2016 were as follows: March 31, 2017 December 31, 2016 Loss reserves recoverable on unpaid: Case reserves $ 175,863 $ 165,328 IBNR 275,993 265,093 Total loss reserves recoverable 451,856 430,421 Paid losses recoverable 37,837 35,247 Total reinsurance balances recoverable $ 489,693 $ 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 March 31, 2017 , $484,664 or 99.0% ( 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 March 31, 2017 and December 31, 2016 were as follows: March 31, 2017 December 31, 2016 Reinsurance Recoverable % of Total Reinsurance Recoverable % of Total Top 10 reinsurers $ 401,038 81.9 % $ 395,308 84.9 % Other reinsurers’ balances > $1 million 83,242 17.0 % 66,944 14.4 % Other reinsurers’ balances < $1 million 5,413 1.1 % 3,416 0.7 % Total $ 489,693 100.0 % $ 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 March 31, 2017 and December 31, 2016 : March 31, 2017 Top 10 Reinsurers Rating Reinsurance Recoverable % of Total Lloyd's Syndicates A+ $ 79,547 16.2 % Swiss Re AA- 77,143 15.8 % Fully collateralized reinsurers NR 71,014 14.5 % Hannover Re AA- 55,274 11.3 % Everest Re A+ 48,829 10.0 % Munich Re AA- 20,167 4.1 % Transatlantic Re A+ 18,222 3.7 % XL Catlin A+ 12,652 2.6 % Hamilton Re A- 9,874 2.0 % Helvetia Group A 8,316 1.7 % Total $ 401,038 81.9 % 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 March 31, 2017 and December 31, 2016 , the provision for uncollectible reinsurance relating to reinsurance balances recoverable was $6,019 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	3 Months Ended
	Mar. 31, 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 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 Company had 6,000 Series A Preferred Shares issued and outstanding as at both March 31, 2017 and 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 80,508,849 common shares for an aggregate purchase price of $2,704,406 from the inception of its share repurchase program to March 31, 2017 . The Company had $319,995 remaining under its authorized share repurchase program as of March 31, 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 three months ended March 31, 2017 and 2016 : Three Months Ended March 31, 2017 2016 Common shares issued, beginning of period 161,279,976 160,570,772 Restricted share awards vested, net of shares withheld 3,440 9,566 Restricted share units vested, net of shares withheld 1,995 1,939 Common shares issued, end of period 161,285,411 160,582,277 Treasury shares, end of period (82,147,821 ) (79,026,791 ) Common shares outstanding, end of period 79,137,590 81,555,486 (c) Dividends On February 9, 2017 , the Company announced a quarterly cash dividend of $0.38 ( 2016 : $0.35 ) per common share and a quarterly 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	3 Months Ended
	Mar. 31, 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 1,275,446 shares remain available for issuance at March 31, 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 three months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 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 — — — — — — Options outstanding, end of period 26,136 $ 6.78 $ 23.48 65,401 $ 7.74 $ 20.17 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 during the three months ended March 31, 2017 of $9,044 ( 2016 : $9,129 ). 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 three months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 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 2,082 57.66 — — Restricted share awards vested (4,571 ) 37.93 (12,550 ) 35.75 Restricted share awards forfeited (513 ) 48.69 (8,317 ) 37.94 Restricted share awards outstanding, end of period 2,466,980 $ 40.91 2,718,579 $ 38.26 At March 31, 2017 , there were $50,207 ( 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 2.1 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 during the three months ended March 31, 2017 of $315 ( 2016 : $311 ). 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 three months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 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 vested (2,115 ) 38.24 (2,056 ) 38.24 Restricted share units issued in lieu of cash dividends 717 40.95 790 38.47 Restricted share units outstanding, end of period 111,410 $ 41.01 113,071 $ 38.47 At March 31, 2017 , there were $2,241 ( 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 2.4 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 during the three months ended March 31, 2017 of $132 ( 2016 : $1,797 ). Activity with respect to unvested performance share awards for the three months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 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 conversion adjustment (26,322 ) 36.82 45,517 36.82 Performance share awards outstanding, end of period 259,498 $ 45.26 218,111 $ 39.89 At March 31, 2017 , there were $5,848 ( 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 1.9 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 March 31, 2017 2016 Restricted share awards $ 9,044 $ 9,129 Restricted share units 315 311 Performance share awards 132 1,797 Total $ 9,491 $ 11,237

Debt and financing arrangements

Debt and financing arrangements	3 Months Ended
	Mar. 31, 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. The Company’s outstanding debentures and senior notes payable as at March 31, 2017 and December 31, 2016 were as follows: March 31, 2017 December 31, 2016 Deferrable debentures 2006 Junior Subordinated $ 150,000 $ 150,000 2007 Junior Subordinated 139,800 139,800 Flagstone 2006 Junior Subordinated 133,852 133,676 Flagstone 2007 Junior Subordinated 113,750 113,750 Total debentures payable 537,402 537,226 2010 Senior notes payable 250,000 250,000 Less: Unamortized debt issuance costs (4,588 ) (4,638 ) Total senior notes payable 245,412 245,362 Total debentures and senior notes payable $ 782,814 $ 782,588 The Company’s outstanding credit and other facilities as at March 31, 2017 and December 31, 2016 were as follows: March 31, 2017 December 31, 2016 Commitment Drawn and outstanding Commitment Drawn and outstanding Credit and other facilities $85,000 syndicated unsecured letter of credit facility $ 85,000 $ — $ 85,000 $ — $300,000 syndicated secured letter of credit facility 300,000 83,655 300,000 90,252 $24,000 secured bi-lateral letter of credit facility 24,000 2,590 24,000 4,553 $20,000 AlphaCat Re secured letter of credit facility (a) — — 20,000 20,000 $25,000 IPC bi-lateral facility 25,000 4,952 25,000 5,842 $236,000 Flagstone bi-lateral facility 236,000 144,158 236,000 144,392 Total credit and other facilities $ 670,000 $ 235,355 $ 690,000 $ 265,039 (a) The Company terminated its AlphaCat Re secured letter of credit facility on January 6, 2017. (a) Senior notes and junior subordinated deferrable debentures 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 March 31, 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 $ 133,852 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 $537,402 on the 2010 Senior Notes and the debentures, respectively, are expected to be made after 2022. (b) Credit facilities The Company has pledged cash and investments as collateral under the Company’s credit facilities in the total amount of $412,176 (December 31, 2016 : $442,184 ) as detailed in the table below: Cash and investments pledged as collateral Description March 31, 2017 December 31, 2016 $300,000 syndicated secured letter of credit facility $ 146,375 $ 157,597 $24,000 secured bi-lateral letter of credit facility 48,219 48,097 AlphaCat Re secured letter of credit facility (a) — 20,032 $236,000 Flagstone bi-lateral facility 217,582 216,458 Total $ 412,176 $ 442,184 (a) The Company terminated its AlphaCat Re secured letter of credit facility on January 6, 2017. As of March 31, 2017 and December 31, 2016 , the Company was in compliance with all covenants and restrictions under its credit 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, Talbot Funds at Lloyds (“FAL”) facility, AlphaCat financing fees and other charges as follows: Three Months Ended March 31, 2017 2016 2006 Junior Subordinated Deferrable Debentures $ 2,187 $ 2,211 2007 Junior Subordinated Deferrable Debentures 1,810 1,831 Flagstone 2006 Junior Subordinated Deferrable Debentures 2,221 2,245 Flagstone 2007 Junior Subordinated Deferrable Debentures 1,723 1,767 2010 Senior Notes due 2040 5,597 5,597 Credit facilities 218 661 Bank and other charges 151 7 AlphaCat fees (a) 36 884 Total finance expenses $ 13,943 $ 15,203 (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	3 Months Ended
	Mar. 31, 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 months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 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, net of tax 597 68 98 763 Balance, net of tax, end of period $ (21,677 ) $ (82 ) $ (694 ) $ (22,453 ) Three Months Ended March 31, 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 (2,028 ) (83 ) (758 ) (2,869 ) Balance, net of tax, end of period $ (13,862 ) $ 251 $ (1,827 ) $ (15,438 )

Commitments and contingencies

Commitments and contingencies	3 Months Ended
	Mar. 31, 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 March 31, 2017 exchange rate of £1 equals $1.26 and assuming the maximum 3% assessment, the Company would be assessed approximately $22,680 . (c) Unfunded investment commitments As at March 31, 2017 and December 31, 2016 , the Company had total unfunded investment commitments related to the following: Unfunded investment commitments as at March 31, 2017 December 31, 2016 Fixed maturity investments $ 27,375 $ 28,499 Other investments (a) 138,636 156,134 Investments in investment affiliates (b) 84,861 64,071 AlphaCat ILS Fund 8,000 10,000 Total unfunded investment commitments $ 258,872 $ 258,704 (a) The Company’s total capital commitments related to other investments as at both March 31, 2017 and December 31, 2016 was $308,000 . (b) Refer to Note 3(c), “Investments in Investment Affiliates.”

Related party transactions

Related party transactions	3 Months Ended
	Mar. 31, 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, reinsurance premiums ceded and earned premium adjustments during the three months ended March 31, 2016 of $1,906 , $17 and $526 , 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 months ended March 31, 2017 the Company recognized gross premiums written and earned premium adjustments of $2,974 and $861 ( 2016 : $nil and $ nil ), respectively. As at March 31, 2017 and December 31, 2016 the Company had recorded premiums receivable of $2,676 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 March 31, 2017 and December 31, 2016 , investments in Aquiline II, III and Tech with a total value of $94,697 and $100,431 and outstanding unfunded commitments of $84,861 and $64,071 , respectively. For the three months ended March 31, 2017 , the Company incurred $356 ( 2016 : $nil ) in partnership fees associated with these investments. Additional information related to Aquiline II, III and Tech is disclosed in Note 3(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	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Earnings per 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 months ended March 31, 2017 and 2016 : Three Months Ended March 31, 2017 2016 Basic earnings per common share Net income available to Validus common shareholders $ 94,561 $ 166,810 Weighted average number of common shares outstanding 79,133,671 82,821,261 Basic earnings per share available to Validus common shareholders $ 1.19 $ 2.01 Earnings per diluted common share Net income available to Validus common shareholders $ 94,561 $ 166,810 Weighted average number of common shares outstanding 79,133,671 82,821,261 Share equivalents: Stock options 15,379 35,878 Unvested restricted shares 1,590,092 1,341,176 Weighted average number of diluted common shares outstanding 80,739,142 84,198,315 Earnings per diluted share available to Validus common shareholders $ 1.17 $ 1.98 Share equivalents that would result in the issuance of 1,503 common shares were outstanding for the three months ended March 31, 2017 , but were not included in the computation of earnings per diluted common share because the effect would be antidilutive. There were no antidilutive shares noted for the three months ended March 31, 2016 .

Segment information

Segment information	3 Months Ended
	Mar. 31, 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. 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 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 and finance expenses. 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. A reconciliation of segmental income to net income available to Validus is included in the tables below. The following tables summarize the results of our operating segments and “Corporate and Investments”: Three Months Ended March 31, Validus Re Segment Information 2017 2016 Underwriting revenues Gross premiums written $ 620,522 $ 691,668 Reinsurance premiums ceded (108,813 ) (92,495 ) Net premiums written 511,709 599,173 Change in unearned premiums (293,297 ) (355,342 ) Net premiums earned 218,412 243,831 Other insurance related income (loss) 78 (315 ) Total underwriting revenues 218,490 243,516 Underwriting deductions Losses and loss expenses 86,154 82,868 Policy acquisition costs 41,256 42,259 General and administrative expenses 16,832 17,179 Share compensation expenses 2,477 2,901 Total underwriting deductions 146,719 145,207 Underwriting income $ 71,771 $ 98,309 Selected ratios Ratio of net to gross premiums written 82.5 % 86.6 % Losses and loss expense ratio 39.4 % 34.0 % Policy acquisition cost ratio 18.9 % 17.4 % General and administrative expense ratio (a) 8.9 % 8.2 % Expense ratio 27.8 % 25.6 % Combined ratio 67.2 % 59.6 % (a) The general and administrative expense ratio includes share compensation expenses. Three Months Ended March 31, Talbot Segment Information 2017 2016 Underwriting revenues Gross premiums written $ 247,175 $ 266,317 Reinsurance premiums ceded (92,824 ) (87,458 ) Net premiums written 154,351 178,859 Change in unearned premiums 40,714 27,933 Net premiums earned 195,065 206,792 Other insurance related income 755 11 Total underwriting revenues 195,820 206,803 Underwriting deductions Losses and loss expenses 106,412 100,101 Policy acquisition costs 43,276 44,343 General and administrative expenses 38,443 38,535 Share compensation expenses 2,827 3,522 Total underwriting deductions 190,958 186,501 Underwriting income $ 4,862 $ 20,302 Selected ratios Ratio of net to gross premiums written 62.4 % 67.2 % Losses and loss expense ratio 54.6 % 48.4 % Policy acquisition cost ratio 22.2 % 21.5 % General and administrative expense ratio (a) 21.1 % 20.3 % Expense ratio 43.3 % 41.8 % Combined ratio 97.9 % 90.2 % (a) The general and administrative expense ratio includes share compensation expenses. Three Months Ended March 31, Western World Segment Information 2017 2016 Underwriting revenues Gross premiums written $ 172,043 $ 63,959 Reinsurance premiums ceded (5,618 ) (4,139 ) Net premiums written 166,425 59,820 Change in unearned premiums (69,153 ) 1,679 Net premiums earned 97,272 61,499 Other insurance related income 241 288 Total underwriting revenues 97,513 61,787 Underwriting deductions Losses and loss expenses 74,925 39,646 Policy acquisition costs 20,236 14,200 General and administrative expenses 10,754 12,075 Share compensation expenses 692 581 Total underwriting deductions 106,607 66,502 Underwriting loss $ (9,094 ) $ (4,715 ) Selected ratios Ratio of net to gross premiums written 96.7 % 93.5 % Losses and loss expense ratio 77.0 % 64.5 % Policy acquisition cost ratio 20.8 % 23.1 % General and administrative expense ratio (a) 11.8 % 20.5 % Expense ratio 32.6 % 43.6 % Combined ratio 109.6 % 108.1 % (a) The general and administrative expense ratio includes share compensation expenses. Three Months Ended March 31, AlphaCat Segment Information 2017 2016 Revenues Third party $ 4,644 $ 4,727 Related party 631 891 Total revenues 5,275 5,618 Expenses General and administrative expenses 3,844 1,482 Share compensation expenses 82 141 Finance expenses 31 808 Tax benefit (1 ) — Foreign exchange (gains) losses (1 ) 8 Total expenses 3,955 2,439 Income before investments from AlphaCat Funds and Sidecars 1,320 3,179 Investment income (loss) from AlphaCat Funds and Sidecars (a) AlphaCat Sidecars (112 ) 124 AlphaCat ILS Funds - Lower Risk (b) 2,189 2,507 AlphaCat ILS Funds - Higher Risk (b) 2,367 2,436 BetaCat ILS Funds 368 563 PaCRe — (23 ) Total investment income from AlphaCat Funds and Sidecars 4,812 5,607 Validus’ share of AlphaCat segment income $ 6,132 $ 8,786 Supplemental information Gross premiums written AlphaCat Sidecars $ 66 $ (52 ) AlphaCat ILS Funds - Lower Risk (b) 52,908 59,958 AlphaCat ILS Funds - Higher Risk (b) 93,536 96,320 AlphaCat Direct (c) 18,416 11,122 Total gross premiums written $ 164,926 $ 167,348 (a) The investment 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 March 31, Corporate and Investments 2017 2016 Investment income Managed net investment income (a) $ 36,192 $ 27,923 Corporate expenses General and administrative expenses 17,177 16,183 Share compensation expenses 3,413 4,092 Finance expenses (a) 13,864 14,341 Dividends on preferred shares 2,203 — Tax benefit (3,548 ) (2,118 ) Total Corporate expenses 33,109 32,498 Other items Net realized losses on managed investments (a) (2,892 ) (1,086 ) Change in net unrealized gains on managed investments (a) 14,349 47,078 Income (loss) from investment affiliate 5,188 (4,113 ) Foreign exchange gains (a) 1,103 6,074 Other income 94 677 Total other items 17,842 48,630 Total Corporate and Investments $ 20,925 $ 44,055 (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 March 31, 2017 Validus Re Segment Talbot Segment Western World Segment AlphaCat Segment and Consolidated VIEs Corporate and Investments Eliminations Total Underwriting revenues Gross premiums written $ 620,522 $ 247,175 $ 172,043 $ 164,926 $ — $ (13,809 ) $ 1,190,857 Reinsurance premiums ceded (108,813 ) (92,824 ) (5,618 ) (6,660 ) — 13,809 (200,106 ) Net premiums written 511,709 154,351 166,425 158,266 — — 990,751 Change in unearned premiums (293,297 ) 40,714 (69,153 ) (93,639 ) — — (415,375 ) Net premiums earned 218,412 195,065 97,272 64,627 — — 575,376 Other insurance related income 78 755 241 5,161 — (4,999 ) 1,236 Total underwriting revenues 218,490 195,820 97,513 69,788 — (4,999 ) 576,612 Underwriting deductions Losses and loss expenses 86,154 106,412 74,925 2,094 — — 269,585 Policy acquisition costs 41,256 43,276 20,236 6,901 — (41 ) 111,628 General and administrative expenses 16,832 38,443 10,754 9,641 17,177 (4,923 ) 87,924 Share compensation expenses 2,477 2,827 692 82 3,413 — 9,491 Total underwriting deductions 146,719 190,958 106,607 18,718 20,590 (4,964 ) 478,628 Underwriting income (loss) $ 71,771 $ 4,862 $ (9,094 ) $ 51,070 $ (20,590 ) $ (35 ) $ 97,984 Other items (a) — — — 1,115 7,526 — 8,641 Dividends on preferred shares — — — — (2,203 ) — (2,203 ) Net investment income — — — 4,022 36,192 — 40,214 (Income) attributable to AlphaCat investors — — — (7,503 ) — — (7,503 ) Net (income) attributable to noncontrolling interest — — — (42,572 ) — — (42,572 ) Segmental income (loss) $ 71,771 $ 4,862 $ (9,094 ) $ 6,132 $ 20,925 $ (35 ) Net income available to Validus common shareholders $ 94,561 (a) Other items includes finance expenses, tax expenses, foreign exchange gains (losses), net realized and change in net unrealized gains (losses) on investments, income from investment and operating affiliates and other income (loss). Three Months Ended March 31, 2016 Validus Re Segment Talbot Segment Western World Segment AlphaCat Segment and Consolidated VIEs Corporate and Investments Eliminations Total Underwriting revenues Gross premiums written $ 691,668 $ 266,317 $ 63,959 $ 167,348 $ — $ (16,501 ) $ 1,172,791 Reinsurance premiums ceded (92,495 ) (87,458 ) (4,139 ) (244 ) — 16,501 (167,835 ) Net premiums written 599,173 178,859 59,820 167,104 — — 1,004,956 Change in unearned premiums (355,342 ) 27,933 1,679 (107,958 ) — — (433,688 ) Net premiums earned 243,831 206,792 61,499 59,146 — — 571,268 Other insurance related (loss) income (315 ) 11 288 5,665 — (4,913 ) 736 Total underwriting revenues 243,516 206,803 61,787 64,811 — (4,913 ) 572,004 Underwriting deductions Losses and loss expenses 82,868 100,101 39,646 1,832 — — 224,447 Policy acquisition costs 42,259 44,343 14,200 6,157 — 234 107,193 General and administrative expenses 17,179 38,535 12,075 7,456 16,183 (5,220 ) 86,208 Share compensation expenses 2,901 3,522 581 141 4,092 — 11,237 Total underwriting deductions 145,207 186,501 66,502 15,586 20,275 (4,986 ) 429,085 Underwriting income (loss) $ 98,309 $ 20,302 $ (4,715 ) $ 49,225 $ (20,275 ) $ 73 $ 142,919 Other items (a) — — — 154 36,407 — 36,561 Dividends on preferred shares — — — — — — — Net investment income — — — 1,538 27,923 — 29,461 (Income) attributable to AlphaCat investors — — — (4,600 ) — — (4,600 ) Net (income) attributable to noncontrolling interest — — — (37,531 ) — — (37,531 ) Segmental income (loss) $ 98,309 $ 20,302 $ (4,715 ) $ 8,786 $ 44,055 $ 73 Net income available to Validus common shareholders $ 166,810 (a) Other items includes finance expenses, tax expenses, foreign exchange gains (losses), net realized and change in net unrealized gains (losses) on investments, income from investment and operating affiliates 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 March 31, 2017 Validus Re Talbot Western World AlphaCat Eliminations Total % United States $ 213,868 $ 29,085 $ 172,043 $ 28,203 $ (880 ) $ 442,319 37.1 % Worldwide excluding United States (a) 34,068 34,331 — 7,035 (653 ) 74,781 6.3 % Australia and New Zealand 931 3,182 — — (150 ) 3,963 0.3 % Europe 29,616 11,715 — 466 (705 ) 41,092 3.5 % Latin America and Caribbean 9,342 24,177 — — (2,872 ) 30,647 2.6 % Japan 1,161 1,825 — 1,193 (30 ) 4,149 0.3 % Canada 1,715 1,137 — — (45 ) 2,807 0.2 % Rest of the world (b) 13,905 23,272 — — (1,682 ) 35,495 3.0 % Sub-total, non United States 90,738 99,639 — 8,694 (6,137 ) 192,934 16.2 % Worldwide including United States (a) 102,421 27,357 — 123,309 (6,790 ) 246,297 20.7 % Other locations non-specific (c) 213,495 91,094 — 4,720 (2 ) 309,307 26.0 % Total $ 620,522 $ 247,175 $ 172,043 $ 164,926 $ (13,809 ) $ 1,190,857 100.0 % Gross Premiums Written Three Months Ended March 31, 2016 Validus Re Talbot Western World AlphaCat Eliminations Total % United States $ 295,394 $ 26,110 $ 63,959 $ 25,391 $ (1,138 ) $ 409,716 35.0 % Worldwide excluding United States (a) 30,264 35,504 — 16,011 (475 ) 81,304 6.9 % Australia and New Zealand 4,923 2,312 — 4,082 (134 ) 11,183 1.0 % Europe 22,467 13,861 — 3,451 (924 ) 38,855 3.3 % Latin America and Caribbean 13,582 23,807 — — (3,026 ) 34,363 2.9 % Japan 872 617 — 1,500 (24 ) 2,965 0.3 % Canada 1,676 1,092 — — (51 ) 2,717 0.2 % Rest of the world (b) 16,688 27,484 — — (1,885 ) 42,287 3.6 % Sub-total, non United States 90,472 104,677 — 25,044 (6,519 ) 213,674 18.2 % Worldwide including United States (a) 111,777 28,454 — 115,373 (8,834 ) 246,770 21.0 % Other locations non-specific (c) 194,025 107,076 — 1,540 (10 ) 302,631 25.8 % Total $ 691,668 $ 266,317 $ 63,959 $ 167,348 $ (16,501 ) $ 1,172,791 100.0 % (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	3 Months Ended
	Mar. 31, 2017
Subsequent Events [Abstract]
Subsequent events	Subsequent events On May 1, 2017, the Company completed its acquisition of Archer Daniels Midland Company’s (“ADM”) Crop Risk Services business (“CRS”). Under the terms of the transaction, ADM received $127,500 in cash, subject to certain working capital and balance sheet adjustments, in exchange for 100% of the outstanding stock of CRS.

Significant accounting policies

Significant accounting policies (Policies)	3 Months Ended
	Mar. 31, 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.

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2017 and December 31, 2016 were as follows: March 31, 2017 December 31, 2016 Amortized Amortized Fair Value Managed investments U.S. government and government agency $ 721,859 $ 718,025 $ 809,392 $ 804,126 Non-U.S. government and government agency 261,860 258,463 245,651 240,791 U.S. states, municipalities and political subdivisions 228,818 229,129 271,742 271,830 Agency residential mortgage-backed securities 658,476 653,395 684,490 679,595 Non-agency residential mortgage-backed securities 19,678 19,382 15,858 15,477 U.S. corporate 1,484,897 1,486,882 1,540,036 1,534,508 Non-U.S. corporate 403,471 397,989 418,520 410,227 Bank loans 573,263 567,012 579,121 570,399 Asset-backed securities 515,219 514,690 528,563 526,814 Commercial mortgage-backed securities 321,562 318,288 333,740 330,932 Total fixed maturities 5,189,103 5,163,255 5,427,113 5,384,699 Short-term investments 232,961 232,955 228,574 228,386 Other investments Fund of hedge funds 1,457 996 1,457 955 Hedge funds 11,292 17,624 11,292 17,381 Private equity investments 78,871 95,927 66,383 82,627 Fixed income investment funds 267,425 269,113 247,967 249,275 Overseas deposits 53,709 53,709 50,106 50,106 Mutual funds 2,925 5,635 2,925 5,368 Total other investments 415,679 443,004 380,130 405,712 Investments in investment affiliates (a) 73,918 94,697 84,840 100,431 Total managed investments $ 5,911,661 $ 5,933,911 $ 6,120,657 $ 6,119,228 Non-managed investments Catastrophe bonds $ 202,000 $ 201,961 $ 157,486 $ 158,331 Short-term investments 2,552,271 2,552,271 2,567,784 2,567,784 Total non-managed investments 2,754,271 2,754,232 2,725,270 2,726,115 Total investments $ 8,665,932 $ 8,688,143 $ 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 March 31, 2017 and December 31, 2016 . March 31, 2017 December 31, 2016 Fair Value % of Total Fair Value % of Total Managed fixed maturities AAA $ 2,265,668 42.2 % $ 2,405,597 43.4 % AA 533,767 9.9 % 538,289 9.7 % A 1,000,955 18.7 % 1,081,949 19.5 % BBB 730,325 13.6 % 740,861 13.4 % Total investment grade managed fixed maturities 4,530,715 84.4 % 4,766,696 86.0 % BB 236,477 4.4 % 213,568 3.9 % B 167,170 3.1 % 177,737 3.2 % CCC 11,818 0.2 % 13,371 0.2 % NR 217,075 4.1 % 213,327 3.8 % Total non-investment grade fixed maturities 632,540 11.8 % 618,003 11.1 % Total managed fixed maturities $ 5,163,255 96.2 % $ 5,384,699 97.1 % Non-managed fixed maturities BB 25,275 0.5 % 29,731 0.6 % B 4,509 0.1 % 4,524 0.1 % NR 172,177 3.2 % 124,076 2.2 % Total non-managed fixed maturities 201,961 3.8 % 158,331 2.9 % Total fixed maturities $ 5,365,216 100.0 % $ 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 March 31, 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. March 31, 2017 December 31, 2016 Amortized Cost Fair Value Amortized Cost Fair Value Managed fixed maturities Due in one year or less $ 438,198 $ 433,710 $ 350,733 $ 346,161 Due after one year through five years 2,703,019 2,691,398 2,954,856 2,933,146 Due after five years through ten years 443,791 443,221 430,365 426,647 Due after ten years 89,160 89,171 128,508 125,927 3,674,168 3,657,500 3,864,462 3,831,881 Asset-backed and mortgage-backed securities 1,514,935 1,505,755 1,562,651 1,552,818 Total managed fixed maturities $ 5,189,103 $ 5,163,255 $ 5,427,113 $ 5,384,699 Non-managed catastrophe bonds Due in one year or less $ 43,052 $ 41,242 $ 43,664 $ 45,418 Due after one year through five years 157,698 159,463 112,572 111,656 Due after five years through ten years 1,250 1,256 1,250 1,257 Due after ten years — — — — Total non-managed fixed maturities 202,000 201,961 157,486 158,331 Total fixed maturities $ 5,391,103 $ 5,365,216 $ 5,584,599 $ 5,543,030
Other investments	The following tables set forth certain information regarding the Company’s other investment portfolio as at March 31, 2017 and December 31, 2016 : March 31, 2017 Fair Value Investments with redemption restrictions Investments without redemption restrictions Redemption frequency (a) Redemption notice period (a) Fund of hedge funds $ 996 $ 996 $ — Hedge funds 17,624 17,624 — Private equity investments 95,927 95,927 — Fixed income investment funds 269,113 229,790 39,323 Daily Daily to 2 days Overseas deposits 53,709 53,709 — Mutual funds 5,635 — 5,635 Daily Daily Total other investments $ 443,004 $ 398,046 $ 44,958 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 months ended March 31, 2017 and 2016 : Three Months Ended March 31, 2017 2016 Investments in investment affiliates, beginning of period $ 100,431 $ 87,673 Net capital (distributions) contributions (10,922 ) 575 Income (loss) from investment affiliates 5,188 (4,113 ) Investments in investment affiliates, end of period $ 94,697 $ 84,135
Schedule of equity method investments	The following table presents the Company’s investments in investment affiliates as at March 31, 2017 and December 31, 2016 : March 31, 2017 Investment at cost Voting ownership % Equity ownership % Carrying value Aquiline II $ 35,949 — % 8.1 % $ 54,524 Aquiline III 37,969 — % 9.0 % 40,173 Aquiline Tech — — % 16.4 % — Total investments in investment affiliates $ 73,918 $ 94,697 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 March 31, 2017 2016 Managed investments Fixed maturities and short-term investments $ 31,671 $ 28,017 Other investments 6,870 872 Cash and cash equivalents and restricted cash 610 865 Securities lending income 13 5 Total gross investment income 39,164 29,759 Investment expenses (2,972 ) (1,836 ) Total managed net investment income $ 36,192 $ 27,923 Non managed investments Fixed maturities and short-term investments $ 3,060 $ 1,295 Restricted cash, cash and cash equivalents 962 243 Total non-managed net investment income 4,022 1,538 Total net investment income $ 40,214 $ 29,461
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 losses and the change in net unrealized gains on investments: Three Months Ended March 31, 2017 2016 Managed fixed maturities, short-term and other investments Gross realized gains $ 2,690 $ 3,217 Gross realized (losses) (5,582 ) (4,303 ) Net realized losses on investments (2,892 ) (1,086 ) Change in net unrealized gains on investments 14,349 47,078 Total net realized and change in net unrealized gains on managed investments $ 11,457 $ 45,992 Non-managed fixed maturities, short-term and other investments Gross realized gains $ 1,728 $ 511 Gross realized (losses) — (9 ) Net realized gains on investments 1,728 502 Change in net unrealized (losses) gains on investments (1,001 ) 366 Total net realized and change in net unrealized gains on non-managed investments 727 868 Total net realized and change in net unrealized gains on total investments $ 12,184 $ 46,860

Fair value measurements (Tables

Fair value measurements (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair value hierarchy - allocation of investments	At March 31, 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 $ — $ 718,025 $ — $ — $ 718,025 Non-U.S. government and government agency — 258,463 — — 258,463 U.S. states, municipalities and political subdivisions — 229,129 — — 229,129 Agency residential mortgage-backed securities — 653,395 — — 653,395 Non-agency residential mortgage-backed securities — 19,382 — — 19,382 U.S. corporate — 1,486,882 — — 1,486,882 Non-U.S. corporate — 397,989 — — 397,989 Bank loans — 330,318 236,694 — 567,012 Asset-backed securities — 490,808 23,882 — 514,690 Commercial mortgage-backed securities — 318,288 — — 318,288 Total fixed maturities — 4,902,679 260,576 — 5,163,255 Short-term investments 214,859 18,096 — — 232,955 Other investments Fund of hedge funds — — — 996 996 Hedge funds — — — 17,624 17,624 Private equity investments — — — 95,927 95,927 Fixed income investment funds — 39,323 12,560 217,230 269,113 Overseas deposits — — — 53,709 53,709 Mutual funds — 5,635 — — 5,635 Total other investments — 44,958 12,560 385,486 443,004 Investments in investment affiliates (b) — — — — 94,697 Total managed investments $ 214,859 $ 4,965,733 $ 273,136 $ 385,486 $ 5,933,911 Non-managed investments Catastrophe bonds $ — $ 129,285 $ 72,676 $ — $ 201,961 Short-term investments 2,552,271 — — — 2,552,271 Total non-managed investments 2,552,271 129,285 72,676 — 2,754,232 Total investments $ 2,767,130 $ 5,095,018 $ 345,812 $ 385,486 $ 8,688,143 (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 months ended March 31, 2017 and 2016 : Three Months Ended March 31, 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 23,176 61,091 — — 84,267 Settlements (33,110 ) (38,780 ) 392 — (71,498 ) Net realized gains — 3,134 — — 3,134 Change in net unrealized gains (losses) 132 (1,144 ) — (49 ) (1,061 ) Level 3 investments, end of period $ 236,694 $ 72,676 $ 12,560 $ 23,882 $ 345,812 Three Months Ended March 31, 2016 Bank Loans Catastrophe Bonds Total Level 3 investments, beginning of period $ 232,337 $ 13,500 $ 245,837 Purchases 42,103 23,272 65,375 Sales (2,389 ) — (2,389 ) Settlements (16,249 ) (125 ) (16,374 ) Change in net unrealized (losses) gains (791 ) 458 (333 ) Level 3 investments, end of period $ 255,011 $ 37,105 $ 292,116

Variable interest entities (Tab

Variable interest entities (Tables)	3 Months Ended
	Mar. 31, 2017
Variable Interest Entities Disclosure [Abstract]
Summary of notes payable to variable interest entities	The following table presents a reconciliation of the beginning and ending notes payable to AlphaCat investors as at March 31, 2017 and December 31, 2016 : Three Months Ended March 31, 2017 Variable Funding Notes Structured Notes Total Notes payable to AlphaCat investors, beginning of period $ 278,202 $ — $ 278,202 Issuance of notes payable to AlphaCat investors 274,010 103,320 377,330 Redemption of notes payable to AlphaCat investors (208,956 ) — (208,956 ) Foreign exchange gains — — — Notes payable to AlphaCat investors, end of period $ 343,256 $ 103,320 $ 446,576 Year Ended December 31, 2016 Variable Funding Notes Structured Notes Total Notes payable to AlphaCat investors, beginning of year $ 75,493 $ — $ 75,493 Issuance of notes payable to AlphaCat investors 311,711 94,326 406,037 Redemption of notes payable to AlphaCat investors (109,712 ) (94,326 ) (204,038 ) Foreign exchange gains 710 — 710 Notes payable to AlphaCat investors, end of year $ 278,202 $ — $ 278,202
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 March 31, 2017 and December 31, 2016 : March 31, 2017 December 31, 2016 Total Assets Total Liabilities Total Assets Total Liabilities AlphaCat sidecars $ 28,998 $ 3,196 $ 40,041 $ 3,206 AlphaCat ILS funds - Lower Risk (a) 1,430,039 41,699 1,498,276 42,457 AlphaCat ILS funds - Higher Risk (a) 866,386 143,629 972,633 381,332 AlphaCat Re and AlphaCat Master Fund 2,541,415 2,541,245 2,510,415 2,510,245 BetaCat ILS funds 88,656 219 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)	3 Months Ended
	Mar. 31, 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 months ended March 31, 2017 and 2016 : Redeemable noncontrolling interests Noncontrolling interests Total Three Months Ended March 31, Three Months Ended March 31, Three Months Ended March 31, 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 103,699 268,750 154,980 112,325 258,679 381,075 Income attributable to noncontrolling interests 25,930 28,573 16,642 8,958 42,572 37,531 Redemption of shares / distributions — — (7,002 ) (118,722 ) (7,002 ) (118,722 ) Balance, end of period $ 1,657,630 $ 1,409,037 $ 330,597 $ 157,223 $ 1,988,227 $ 1,566,260 As at March 31, 2017 , redemptions of $3,234 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 (Tables)

Derivative instruments (Tables)	3 Months Ended
	Mar. 31, 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 months ended March 31, 2017 and 2016 : Three Months Ended March 31, Interest rate swap contracts 2017 2016 Amount of effective portion recognized in other comprehensive income $ 2,160 $ 3,656 Amount of effective portion subsequently reclassified to earnings $ (2,257 ) $ (2,898 ) Amount of ineffective portion excluded from effectiveness testing $ 97 $ (758 )
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 March 31, 2017 and December 31, 2016 : March 31, 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 $ 152,683 $ 1,475 $ 1,517 $ 181,375 $ 2,351 $ 3,421 (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 contracts that were not designated as hedging instruments for accounting purposes during the three months ended March 31, 2017 and 2016 : Derivatives not designated as hedging instruments Classification of gains (losses) recognized in earnings Three Months Ended March 31, 2017 2016 Foreign currency forward contracts Foreign exchange gains (losses) $ 453 $ (2,013 ) Foreign currency forward contracts Other (loss) income (105 ) 36
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 March 31, 2017 and December 31, 2016 : March 31, 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 $ 552,563 $ 20 $ 1,314 $ 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 e31

Reserve for losses and loss expenses (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2017 and December 31, 2016 : March 31, 2017 December 31, 2016 Case reserves $ 1,234,156 $ 1,237,772 IBNR 1,818,589 1,757,423 Total reserve for losses and loss expenses $ 3,052,745 $ 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 months ended March 31, 2017 and 2016 : Three Months Ended March 31, 2017 2016 Reserve for losses and loss expenses, beginning of period $ 2,995,195 $ 2,996,567 Loss reserves recoverable (430,421 ) (350,586 ) Net reserves for losses and loss expenses, beginning of period 2,564,774 2,645,981 Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in: Current year 330,816 278,186 Prior years (61,231 ) (53,739 ) Total net incurred losses and loss expenses 269,585 224,447 Less net losses and loss expenses paid in respect of losses occurring in: Current year (7,698 ) (15,774 ) Prior years (238,089 ) (253,303 ) Total net paid losses (245,787 ) (269,077 ) Foreign exchange loss 12,317 8,260 Net reserve for losses and loss expenses, end of period 2,600,889 2,609,611 Loss reserves recoverable 451,856 370,689 Reserve for losses and loss expenses, end of period $ 3,052,745 $ 2,980,300 Incurred losses and loss expenses comprise: Three Months Ended March 31, 2017 2016 Gross losses and loss expenses $ 346,795 $ 269,853 Reinsurance recoverable (77,210 ) (45,406 ) Net incurred losses and loss expenses $ 269,585 $ 224,447
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 months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 2017 Property Marine Specialty Liability Total Validus Re $ (3,571 ) $ (15,429 ) $ (9,780 ) $ — $ (28,780 ) Talbot (6,334 ) (15,996 ) (6,484 ) — (28,814 ) Western World (2,823 ) — — 2,604 (219 ) AlphaCat (4,395 ) — 977 — (3,418 ) Net (favorable) adverse development $ (17,123 ) $ (31,425 ) $ (15,287 ) $ 2,604 $ (61,231 ) The favorable development on prior years was primarily due to favorable development on attritional losses. Three Months Ended March 31, 2016 Property Marine Specialty Liability Total Validus Re $ (22,832 ) $ 3,555 $ (6,407 ) $ — $ (25,684 ) Talbot (18,446 ) 2,964 (7,238 ) — (22,720 ) Western World (441 ) — — (3,985 ) (4,426 ) AlphaCat (181 ) — (728 ) — (909 ) Net favorable development $ (41,900 ) $ 6,519 $ (14,373 ) $ (3,985 ) $ (53,739 ) The Validus Re and Talbot segments experienced favorable development on prior years in the property and specialty lines primarily due to favorable development on attritional losses; whereas, the unfavorable development in the marine lines was primarily driven by adverse development on events, which included unfavorable development on an individual marine policy that incepted during the second half of 2015. This adverse development was partially offset by favorable development on attritional losses. The Western World segment experienced favorable development on prior years primarily due to favorable development on attritional losses.

Reinsurance (Tables)

Reinsurance (Tables)	3 Months Ended
	Mar. 31, 2017
Reinsurance Disclosures [Abstract]
Schedule of reinsurance recoverable	The Company’s reinsurance balances recoverable at March 31, 2017 and December 31, 2016 were as follows: March 31, 2017 December 31, 2016 Loss reserves recoverable on unpaid: Case reserves $ 175,863 $ 165,328 IBNR 275,993 265,093 Total loss reserves recoverable 451,856 430,421 Paid losses recoverable 37,837 35,247 Total reinsurance balances recoverable $ 489,693 $ 465,668
Reinsurance recoverables by reinsurer	Reinsurance balances recoverable by reinsurer as at March 31, 2017 and December 31, 2016 were as follows: March 31, 2017 December 31, 2016 Reinsurance Recoverable % of Total Reinsurance Recoverable % of Total Top 10 reinsurers $ 401,038 81.9 % $ 395,308 84.9 % Other reinsurers’ balances > $1 million 83,242 17.0 % 66,944 14.4 % Other reinsurers’ balances < $1 million 5,413 1.1 % 3,416 0.7 % Total $ 489,693 100.0 % $ 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 March 31, 2017 and December 31, 2016 : March 31, 2017 Top 10 Reinsurers Rating Reinsurance Recoverable % of Total Lloyd's Syndicates A+ $ 79,547 16.2 % Swiss Re AA- 77,143 15.8 % Fully collateralized reinsurers NR 71,014 14.5 % Hannover Re AA- 55,274 11.3 % Everest Re A+ 48,829 10.0 % Munich Re AA- 20,167 4.1 % Transatlantic Re A+ 18,222 3.7 % XL Catlin A+ 12,652 2.6 % Hamilton Re A- 9,874 2.0 % Helvetia Group A 8,316 1.7 % Total $ 401,038 81.9 % 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)	3 Months Ended
	Mar. 31, 2017
Stockholders' Equity Note [Abstract]
Summary of common shares issued and outstanding	The following table is a summary of the common share activity during the three months ended March 31, 2017 and 2016 : Three Months Ended March 31, 2017 2016 Common shares issued, beginning of period 161,279,976 160,570,772 Restricted share awards vested, net of shares withheld 3,440 9,566 Restricted share units vested, net of shares withheld 1,995 1,939 Common shares issued, end of period 161,285,411 160,582,277 Treasury shares, end of period (82,147,821 ) (79,026,791 ) Common shares outstanding, end of period 79,137,590 81,555,486

Stock plans (Tables)

Stock plans (Tables)	3 Months Ended
	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Options, activity during the period	Activity with respect to options for the three months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 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 — — — — — — Options outstanding, end of period 26,136 $ 6.78 $ 23.48 65,401 $ 7.74 $ 20.17
Restricted shares awards, activity during the period	Activity with respect to unvested restricted share awards for the three months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 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 2,082 57.66 — — Restricted share awards vested (4,571 ) 37.93 (12,550 ) 35.75 Restricted share awards forfeited (513 ) 48.69 (8,317 ) 37.94 Restricted share awards outstanding, end of period 2,466,980 $ 40.91 2,718,579 $ 38.26
Restricted share units, activity during the period	Activity with respect to unvested restricted share units for the three months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 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 vested (2,115 ) 38.24 (2,056 ) 38.24 Restricted share units issued in lieu of cash dividends 717 40.95 790 38.47 Restricted share units outstanding, end of period 111,410 $ 41.01 113,071 $ 38.47
Performance share awards, activity during the period	Activity with respect to unvested performance share awards for the three months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 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 conversion adjustment (26,322 ) 36.82 45,517 36.82 Performance share awards outstanding, end of period 259,498 $ 45.26 218,111 $ 39.89
Total share compensation expenses	The breakdown of share compensation expenses by award type for the periods indicated was as follows: Three Months Ended March 31, 2017 2016 Restricted share awards $ 9,044 $ 9,129 Restricted share units 315 311 Performance share awards 132 1,797 Total $ 9,491 $ 11,237

Debt and financing arrangemen35

Debt and financing arrangements (Tables)	3 Months Ended
	Mar. 31, 2017
Debt Disclosure [Abstract]
Summary of outstanding debentures and senior notes payable	The Company’s outstanding debentures and senior notes payable as at March 31, 2017 and December 31, 2016 were as follows: March 31, 2017 December 31, 2016 Deferrable debentures 2006 Junior Subordinated $ 150,000 $ 150,000 2007 Junior Subordinated 139,800 139,800 Flagstone 2006 Junior Subordinated 133,852 133,676 Flagstone 2007 Junior Subordinated 113,750 113,750 Total debentures payable 537,402 537,226 2010 Senior notes payable 250,000 250,000 Less: Unamortized debt issuance costs (4,588 ) (4,638 ) Total senior notes payable 245,412 245,362 Total debentures and senior notes payable $ 782,814 $ 782,588
Summary of outstanding credit and other facilities	The Company’s outstanding credit and other facilities as at March 31, 2017 and December 31, 2016 were as follows: March 31, 2017 December 31, 2016 Commitment Drawn and outstanding Commitment Drawn and outstanding Credit and other facilities $85,000 syndicated unsecured letter of credit facility $ 85,000 $ — $ 85,000 $ — $300,000 syndicated secured letter of credit facility 300,000 83,655 300,000 90,252 $24,000 secured bi-lateral letter of credit facility 24,000 2,590 24,000 4,553 $20,000 AlphaCat Re secured letter of credit facility (a) — — 20,000 20,000 $25,000 IPC bi-lateral facility 25,000 4,952 25,000 5,842 $236,000 Flagstone bi-lateral facility 236,000 144,158 236,000 144,392 Total credit and other facilities $ 670,000 $ 235,355 $ 690,000 $ 265,039 (a) The Company terminated its AlphaCat Re secured letter of credit facility on January 6, 2017.
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 March 31, 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 $ 133,852 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.
Investments and cash pledged as collateral under credit facilities	The Company has pledged cash and investments as collateral under the Company’s credit facilities in the total amount of $412,176 (December 31, 2016 : $442,184 ) as detailed in the table below: Cash and investments pledged as collateral Description March 31, 2017 December 31, 2016 $300,000 syndicated secured letter of credit facility $ 146,375 $ 157,597 $24,000 secured bi-lateral letter of credit facility 48,219 48,097 AlphaCat Re secured letter of credit facility (a) — 20,032 $236,000 Flagstone bi-lateral facility 217,582 216,458 Total $ 412,176 $ 442,184
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, Talbot Funds at Lloyds (“FAL”) facility, AlphaCat financing fees and other charges as follows: Three Months Ended March 31, 2017 2016 2006 Junior Subordinated Deferrable Debentures $ 2,187 $ 2,211 2007 Junior Subordinated Deferrable Debentures 1,810 1,831 Flagstone 2006 Junior Subordinated Deferrable Debentures 2,221 2,245 Flagstone 2007 Junior Subordinated Deferrable Debentures 1,723 1,767 2010 Senior Notes due 2040 5,597 5,597 Credit facilities 218 661 Bank and other charges 151 7 AlphaCat fees (a) 36 884 Total finance expenses $ 13,943 $ 15,203 (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 comprehensi36

Accumulated other comprehensive loss (Tables)	3 Months Ended
	Mar. 31, 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 months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 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, net of tax 597 68 98 763 Balance, net of tax, end of period $ (21,677 ) $ (82 ) $ (694 ) $ (22,453 ) Three Months Ended March 31, 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 (2,028 ) (83 ) (758 ) (2,869 ) Balance, net of tax, end of period $ (13,862 ) $ 251 $ (1,827 ) $ (15,438 )

Commitments and contingencies (

Commitments and contingencies (Tables)	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Unfunded investment commitments	As at March 31, 2017 and December 31, 2016 , the Company had total unfunded investment commitments related to the following: Unfunded investment commitments as at March 31, 2017 December 31, 2016 Fixed maturity investments $ 27,375 $ 28,499 Other investments (a) 138,636 156,134 Investments in investment affiliates (b) 84,861 64,071 AlphaCat ILS Fund 8,000 10,000 Total unfunded investment commitments $ 258,872 $ 258,704 (a) The Company’s total capital commitments related to other investments as at both March 31, 2017 and December 31, 2016 was $308,000 . (b) Refer to Note 3(c), “Investments in Investment Affiliates.”

Earnings per share (Tables)

Earnings per share (Tables)	3 Months Ended
	Mar. 31, 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 months ended March 31, 2017 and 2016 : Three Months Ended March 31, 2017 2016 Basic earnings per common share Net income available to Validus common shareholders $ 94,561 $ 166,810 Weighted average number of common shares outstanding 79,133,671 82,821,261 Basic earnings per share available to Validus common shareholders $ 1.19 $ 2.01 Earnings per diluted common share Net income available to Validus common shareholders $ 94,561 $ 166,810 Weighted average number of common shares outstanding 79,133,671 82,821,261 Share equivalents: Stock options 15,379 35,878 Unvested restricted shares 1,590,092 1,341,176 Weighted average number of diluted common shares outstanding 80,739,142 84,198,315 Earnings per diluted share available to Validus common shareholders $ 1.17 $ 1.98

Segment information (Tables)

Segment information (Tables)	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Summary of results of operating segments and Corporate	The following tables summarize the results of our operating segments and “Corporate and Investments”: Three Months Ended March 31, Validus Re Segment Information 2017 2016 Underwriting revenues Gross premiums written $ 620,522 $ 691,668 Reinsurance premiums ceded (108,813 ) (92,495 ) Net premiums written 511,709 599,173 Change in unearned premiums (293,297 ) (355,342 ) Net premiums earned 218,412 243,831 Other insurance related income (loss) 78 (315 ) Total underwriting revenues 218,490 243,516 Underwriting deductions Losses and loss expenses 86,154 82,868 Policy acquisition costs 41,256 42,259 General and administrative expenses 16,832 17,179 Share compensation expenses 2,477 2,901 Total underwriting deductions 146,719 145,207 Underwriting income $ 71,771 $ 98,309 Selected ratios Ratio of net to gross premiums written 82.5 % 86.6 % Losses and loss expense ratio 39.4 % 34.0 % Policy acquisition cost ratio 18.9 % 17.4 % General and administrative expense ratio (a) 8.9 % 8.2 % Expense ratio 27.8 % 25.6 % Combined ratio 67.2 % 59.6 % (a) The general and administrative expense ratio includes share compensation expenses. Three Months Ended March 31, Talbot Segment Information 2017 2016 Underwriting revenues Gross premiums written $ 247,175 $ 266,317 Reinsurance premiums ceded (92,824 ) (87,458 ) Net premiums written 154,351 178,859 Change in unearned premiums 40,714 27,933 Net premiums earned 195,065 206,792 Other insurance related income 755 11 Total underwriting revenues 195,820 206,803 Underwriting deductions Losses and loss expenses 106,412 100,101 Policy acquisition costs 43,276 44,343 General and administrative expenses 38,443 38,535 Share compensation expenses 2,827 3,522 Total underwriting deductions 190,958 186,501 Underwriting income $ 4,862 $ 20,302 Selected ratios Ratio of net to gross premiums written 62.4 % 67.2 % Losses and loss expense ratio 54.6 % 48.4 % Policy acquisition cost ratio 22.2 % 21.5 % General and administrative expense ratio (a) 21.1 % 20.3 % Expense ratio 43.3 % 41.8 % Combined ratio 97.9 % 90.2 % (a) The general and administrative expense ratio includes share compensation expenses. Three Months Ended March 31, Western World Segment Information 2017 2016 Underwriting revenues Gross premiums written $ 172,043 $ 63,959 Reinsurance premiums ceded (5,618 ) (4,139 ) Net premiums written 166,425 59,820 Change in unearned premiums (69,153 ) 1,679 Net premiums earned 97,272 61,499 Other insurance related income 241 288 Total underwriting revenues 97,513 61,787 Underwriting deductions Losses and loss expenses 74,925 39,646 Policy acquisition costs 20,236 14,200 General and administrative expenses 10,754 12,075 Share compensation expenses 692 581 Total underwriting deductions 106,607 66,502 Underwriting loss $ (9,094 ) $ (4,715 ) Selected ratios Ratio of net to gross premiums written 96.7 % 93.5 % Losses and loss expense ratio 77.0 % 64.5 % Policy acquisition cost ratio 20.8 % 23.1 % General and administrative expense ratio (a) 11.8 % 20.5 % Expense ratio 32.6 % 43.6 % Combined ratio 109.6 % 108.1 % (a) The general and administrative expense ratio includes share compensation expenses. Three Months Ended March 31, AlphaCat Segment Information 2017 2016 Revenues Third party $ 4,644 $ 4,727 Related party 631 891 Total revenues 5,275 5,618 Expenses General and administrative expenses 3,844 1,482 Share compensation expenses 82 141 Finance expenses 31 808 Tax benefit (1 ) — Foreign exchange (gains) losses (1 ) 8 Total expenses 3,955 2,439 Income before investments from AlphaCat Funds and Sidecars 1,320 3,179 Investment income (loss) from AlphaCat Funds and Sidecars (a) AlphaCat Sidecars (112 ) 124 AlphaCat ILS Funds - Lower Risk (b) 2,189 2,507 AlphaCat ILS Funds - Higher Risk (b) 2,367 2,436 BetaCat ILS Funds 368 563 PaCRe — (23 ) Total investment income from AlphaCat Funds and Sidecars 4,812 5,607 Validus’ share of AlphaCat segment income $ 6,132 $ 8,786 Supplemental information Gross premiums written AlphaCat Sidecars $ 66 $ (52 ) AlphaCat ILS Funds - Lower Risk (b) 52,908 59,958 AlphaCat ILS Funds - Higher Risk (b) 93,536 96,320 AlphaCat Direct (c) 18,416 11,122 Total gross premiums written $ 164,926 $ 167,348 (a) The investment 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 March 31, Corporate and Investments 2017 2016 Investment income Managed net investment income (a) $ 36,192 $ 27,923 Corporate expenses General and administrative expenses 17,177 16,183 Share compensation expenses 3,413 4,092 Finance expenses (a) 13,864 14,341 Dividends on preferred shares 2,203 — Tax benefit (3,548 ) (2,118 ) Total Corporate expenses 33,109 32,498 Other items Net realized losses on managed investments (a) (2,892 ) (1,086 ) Change in net unrealized gains on managed investments (a) 14,349 47,078 Income (loss) from investment affiliate 5,188 (4,113 ) Foreign exchange gains (a) 1,103 6,074 Other income 94 677 Total other items 17,842 48,630 Total Corporate and Investments $ 20,925 $ 44,055 (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 March 31, 2017 Validus Re Segment Talbot Segment Western World Segment AlphaCat Segment and Consolidated VIEs Corporate and Investments Eliminations Total Underwriting revenues Gross premiums written $ 620,522 $ 247,175 $ 172,043 $ 164,926 $ — $ (13,809 ) $ 1,190,857 Reinsurance premiums ceded (108,813 ) (92,824 ) (5,618 ) (6,660 ) — 13,809 (200,106 ) Net premiums written 511,709 154,351 166,425 158,266 — — 990,751 Change in unearned premiums (293,297 ) 40,714 (69,153 ) (93,639 ) — — (415,375 ) Net premiums earned 218,412 195,065 97,272 64,627 — — 575,376 Other insurance related income 78 755 241 5,161 — (4,999 ) 1,236 Total underwriting revenues 218,490 195,820 97,513 69,788 — (4,999 ) 576,612 Underwriting deductions Losses and loss expenses 86,154 106,412 74,925 2,094 — — 269,585 Policy acquisition costs 41,256 43,276 20,236 6,901 — (41 ) 111,628 General and administrative expenses 16,832 38,443 10,754 9,641 17,177 (4,923 ) 87,924 Share compensation expenses 2,477 2,827 692 82 3,413 — 9,491 Total underwriting deductions 146,719 190,958 106,607 18,718 20,590 (4,964 ) 478,628 Underwriting income (loss) $ 71,771 $ 4,862 $ (9,094 ) $ 51,070 $ (20,590 ) $ (35 ) $ 97,984 Other items (a) — — — 1,115 7,526 — 8,641 Dividends on preferred shares — — — — (2,203 ) — (2,203 ) Net investment income — — — 4,022 36,192 — 40,214 (Income) attributable to AlphaCat investors — — — (7,503 ) — — (7,503 ) Net (income) attributable to noncontrolling interest — — — (42,572 ) — — (42,572 ) Segmental income (loss) $ 71,771 $ 4,862 $ (9,094 ) $ 6,132 $ 20,925 $ (35 ) Net income available to Validus common shareholders $ 94,561 (a) Other items includes finance expenses, tax expenses, foreign exchange gains (losses), net realized and change in net unrealized gains (losses) on investments, income from investment and operating affiliates and other income (loss). Three Months Ended March 31, 2016 Validus Re Segment Talbot Segment Western World Segment AlphaCat Segment and Consolidated VIEs Corporate and Investments Eliminations Total Underwriting revenues Gross premiums written $ 691,668 $ 266,317 $ 63,959 $ 167,348 $ — $ (16,501 ) $ 1,172,791 Reinsurance premiums ceded (92,495 ) (87,458 ) (4,139 ) (244 ) — 16,501 (167,835 ) Net premiums written 599,173 178,859 59,820 167,104 — — 1,004,956 Change in unearned premiums (355,342 ) 27,933 1,679 (107,958 ) — — (433,688 ) Net premiums earned 243,831 206,792 61,499 59,146 — — 571,268 Other insurance related (loss) income (315 ) 11 288 5,665 — (4,913 ) 736 Total underwriting revenues 243,516 206,803 61,787 64,811 — (4,913 ) 572,004 Underwriting deductions Losses and loss expenses 82,868 100,101 39,646 1,832 — — 224,447 Policy acquisition costs 42,259 44,343 14,200 6,157 — 234 107,193 General and administrative expenses 17,179 38,535 12,075 7,456 16,183 (5,220 ) 86,208 Share compensation expenses 2,901 3,522 581 141 4,092 — 11,237 Total underwriting deductions 145,207 186,501 66,502 15,586 20,275 (4,986 ) 429,085 Underwriting income (loss) $ 98,309 $ 20,302 $ (4,715 ) $ 49,225 $ (20,275 ) $ 73 $ 142,919 Other items (a) — — — 154 36,407 — 36,561 Dividends on preferred shares — — — — — — — Net investment income — — — 1,538 27,923 — 29,461 (Income) attributable to AlphaCat investors — — — (4,600 ) — — (4,600 ) Net (income) attributable to noncontrolling interest — — — (37,531 ) — — (37,531 ) Segmental income (loss) $ 98,309 $ 20,302 $ (4,715 ) $ 8,786 $ 44,055 $ 73 Net income available to Validus common shareholders $ 166,810 (a) Other items includes finance expenses, tax expenses, foreign exchange gains (losses), net realized and change in net unrealized gains (losses) on investments, income from investment and operating affiliates 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 March 31, 2017 Validus Re Talbot Western World AlphaCat Eliminations Total % United States $ 213,868 $ 29,085 $ 172,043 $ 28,203 $ (880 ) $ 442,319 37.1 % Worldwide excluding United States (a) 34,068 34,331 — 7,035 (653 ) 74,781 6.3 % Australia and New Zealand 931 3,182 — — (150 ) 3,963 0.3 % Europe 29,616 11,715 — 466 (705 ) 41,092 3.5 % Latin America and Caribbean 9,342 24,177 — — (2,872 ) 30,647 2.6 % Japan 1,161 1,825 — 1,193 (30 ) 4,149 0.3 % Canada 1,715 1,137 — — (45 ) 2,807 0.2 % Rest of the world (b) 13,905 23,272 — — (1,682 ) 35,495 3.0 % Sub-total, non United States 90,738 99,639 — 8,694 (6,137 ) 192,934 16.2 % Worldwide including United States (a) 102,421 27,357 — 123,309 (6,790 ) 246,297 20.7 % Other locations non-specific (c) 213,495 91,094 — 4,720 (2 ) 309,307 26.0 % Total $ 620,522 $ 247,175 $ 172,043 $ 164,926 $ (13,809 ) $ 1,190,857 100.0 % Gross Premiums Written Three Months Ended March 31, 2016 Validus Re Talbot Western World AlphaCat Eliminations Total % United States $ 295,394 $ 26,110 $ 63,959 $ 25,391 $ (1,138 ) $ 409,716 35.0 % Worldwide excluding United States (a) 30,264 35,504 — 16,011 (475 ) 81,304 6.9 % Australia and New Zealand 4,923 2,312 — 4,082 (134 ) 11,183 1.0 % Europe 22,467 13,861 — 3,451 (924 ) 38,855 3.3 % Latin America and Caribbean 13,582 23,807 — — (3,026 ) 34,363 2.9 % Japan 872 617 — 1,500 (24 ) 2,965 0.3 % Canada 1,676 1,092 — — (51 ) 2,717 0.2 % Rest of the world (b) 16,688 27,484 — — (1,885 ) 42,287 3.6 % Sub-total, non United States 90,472 104,677 — 25,044 (6,519 ) 213,674 18.2 % Worldwide including United States (a) 111,777 28,454 — 115,373 (8,834 ) 246,770 21.0 % Other locations non-specific (c) 194,025 107,076 — 1,540 (10 ) 302,631 25.8 % Total $ 691,668 $ 266,317 $ 63,959 $ 167,348 $ (16,501 ) $ 1,172,791 100.0 % (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.

Investments (Amortized cost or

Investments (Amortized cost or cost and fair value of investments) (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		$ 5,391,103	$ 5,584,599
Short-term investments, at amortized cost or cost		2,785,232	2,796,358
Other investments, at amortized cost or cost		415,679	380,130
Investments in investment affiliates, at cost		73,918	84,840
Total investments		8,665,932	8,845,927
Fixed maturities, at fair value		5,365,216	5,543,030
Short-term investments, at fair value		2,785,226	2,796,170
Other investments, at fair value		443,004	405,712
Investments in investment affiliates, at fair value		94,697	100,431
Total investments		8,688,143	8,845,343
Managed investments
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		5,189,103	5,427,113
Short-term investments, at amortized cost or cost		232,961	228,574
Other investments, at amortized cost or cost		415,679	380,130
Investments in investment affiliates, at cost	[1]	73,918	84,840
Total investments		5,911,661	6,120,657
Fixed maturities, at fair value		5,163,255	5,384,699
Short-term investments, at fair value		232,955	228,386
Other investments, at fair value		443,004	405,712
Investments in investment affiliates, at fair value	[1],[2]	94,697	100,431
Total investments		5,933,911	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		721,859	809,392
Fixed maturities, at fair value		718,025	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		261,860	245,651
Fixed maturities, at fair value		258,463	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		228,818	271,742
Fixed maturities, at fair value		229,129	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		658,476	684,490
Fixed maturities, at fair value		653,395	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		19,678	15,858
Fixed maturities, at fair value		19,382	15,477
Managed investments | U.S. corporate
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		1,484,897	1,540,036
Fixed maturities, at fair value		1,486,882	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		403,471	418,520
Fixed maturities, at fair value		397,989	410,227
Managed investments | Bank loans
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		573,263	579,121
Fixed maturities, at fair value		567,012	570,399
Managed investments | Asset-backed securities
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		515,219	528,563
Fixed maturities, at fair value		514,690	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		321,562	333,740
Fixed maturities, at fair value		318,288	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		1,457	1,457
Other investments, at fair value		996	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		17,624	17,381
Managed investments | Private equity investments
Amortized cost (or cost) and estimated fair value of investments
Other investments, at amortized cost or cost		78,871	66,383
Other investments, at fair value		95,927	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		267,425	247,967
Other investments, at fair value		269,113	249,275
Managed investments | Overseas deposits
Amortized cost (or cost) and estimated fair value of investments
Other investments, at amortized cost or cost		53,709	50,106
Other investments, at fair value		53,709	50,106
Managed investments | Mutual funds
Amortized cost (or cost) and estimated fair value of investments
Other investments, at amortized cost or cost		2,925	2,925
Other investments, at fair value		5,635	5,368
Non-managed investments
Amortized cost (or cost) and estimated fair value of investments
Fixed maturities, at amortized cost or cost		202,000	157,486
Short-term investments, at amortized cost or cost		2,552,271	2,567,784
Total investments		2,754,271	2,725,270
Fixed maturities, at fair value		201,961	158,331
Short-term investments, at fair value		2,552,271	2,567,784
Total investments		2,754,232	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		202,000	157,486
Fixed maturities, at fair value		$ 201,961	$ 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.”
[2]	In accordance with ASC Topic 825 “Financial Instruments,” the Company’s investments in investment affiliates have not been classified in the fair value hierarchy.

Investments (Fixed maturities b

Investments (Fixed maturities by investment rating) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fixed Maturities
Fair value	$ 5,365,216	$ 5,543,030
Percentage of total	100.00%	100.00%
Managed investments
Fixed Maturities
Fair value	$ 5,163,255	$ 5,384,699
Percentage of total	96.20%	97.10%
Managed investments | Total investment grade fixed maturities
Fixed Maturities
Fair value	$ 4,530,715	$ 4,766,696
Percentage of total	84.40%	86.00%
Managed investments | Total investment grade fixed maturities | AAA
Fixed Maturities
Fair value	$ 2,265,668	$ 2,405,597
Percentage of total	42.20%	43.40%
Managed investments | Total investment grade fixed maturities | AA
Fixed Maturities
Fair value	$ 533,767	$ 538,289
Percentage of total	9.90%	9.70%
Managed investments | Total investment grade fixed maturities | A rating
Fixed Maturities
Fair value	$ 1,000,955	$ 1,081,949
Percentage of total	18.70%	19.50%
Managed investments | Total investment grade fixed maturities | BBB
Fixed Maturities
Fair value	$ 730,325	$ 740,861
Percentage of total	13.60%	13.40%
Managed investments | Total non-investment grade fixed maturities
Fixed Maturities
Fair value	$ 632,540	$ 618,003
Percentage of total	11.80%	11.10%
Managed investments | Total non-investment grade fixed maturities | BB
Fixed Maturities
Fair value	$ 236,477	$ 213,568
Percentage of total	4.40%	3.90%
Managed investments | Total non-investment grade fixed maturities | B
Fixed Maturities
Fair value	$ 167,170	$ 177,737
Percentage of total	3.10%	3.20%
Managed investments | Total non-investment grade fixed maturities | CCC
Fixed Maturities
Fair value	$ 11,818	$ 13,371
Percentage of total	0.20%	0.20%
Managed investments | Total non-investment grade fixed maturities | NR
Fixed Maturities
Fair value	$ 217,075	$ 213,327
Percentage of total	4.10%	3.80%
Non-managed investments
Fixed Maturities
Fair value	$ 201,961	$ 158,331
Percentage of total	3.80%	2.90%
Non-managed investments | Total non-investment grade fixed maturities | BB
Fixed Maturities
Fair value	$ 25,275	$ 29,731
Percentage of total	0.50%	0.60%
Non-managed investments | Total non-investment grade fixed maturities | B
Fixed Maturities
Fair value	$ 4,509	$ 4,524
Percentage of total	0.10%	0.10%
Non-managed investments | Total non-investment grade fixed maturities | NR
Fixed Maturities
Fair value	$ 172,177	$ 124,076
Percentage of total	3.20%	2.20%

Investments (Maturity profile o

Investments (Maturity profile of fixed maturity investments) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Maturity profile
Amortized cost	$ 5,391,103	$ 5,584,599
Fair value	5,365,216	5,543,030
Managed investments
Maturity profile
Amortized cost	5,189,103	5,427,113
Fair value	5,163,255	5,384,699
Managed investments | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost	3,674,168	3,864,462
Fair value	3,657,500	3,831,881
Managed investments | Due in one year or less | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost	438,198	350,733
Fair value	433,710	346,161
Managed investments | Due after one year through five years | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost	2,703,019	2,954,856
Fair value	2,691,398	2,933,146
Managed investments | Due after five years through ten years | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost	443,791	430,365
Fair value	443,221	426,647
Managed investments | Due after ten years | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost	89,160	128,508
Fair value	89,171	125,927
Managed investments | Asset backed and mortgaged backed securities
Maturity profile
Amortized cost	1,514,935	1,562,651
Fair value	1,505,755	1,552,818
Non-managed investments
Maturity profile
Amortized cost	202,000	157,486
Fair value	201,961	158,331
Non-managed investments | Due in one year or less
Maturity profile
Amortized cost	43,052	43,664
Fair value	41,242	45,418
Non-managed investments | Due after one year through five years
Maturity profile
Amortized cost	157,698	112,572
Fair value	159,463	111,656
Non-managed investments | Due after five years through ten years
Maturity profile
Amortized cost	1,250	1,250
Fair value	1,256	1,257
Non-managed investments | Due after ten years
Maturity profile
Amortized cost	0	0
Fair value	$ 0	$ 0

Investments (Other investments)

Investments (Other investments) (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2017	Dec. 31, 2016
Investment [Line Items]
Other investments, at fair value		$ 443,004	$ 405,712
Managed investments
Investment [Line Items]
Other investments, at fair value		443,004	405,712
Managed investments | Fund of hedge funds
Investment [Line Items]
Other investments, at fair value		996	955
Managed investments | Hedge funds
Investment [Line Items]
Other investments, at fair value		17,624	17,381
Managed investments | Private equity investments
Investment [Line Items]
Other investments, at fair value		95,927	82,627
Managed investments | Fixed income investment funds
Investment [Line Items]
Other investments, at fair value		269,113	249,275
Managed investments | Overseas deposits
Investment [Line Items]
Other investments, at fair value		53,709	50,106
Managed investments | Mutual funds
Investment [Line Items]
Other investments, at fair value		5,635	5,368
Recurring | Managed investments
Investment [Line Items]
Other investments, at fair value		443,004	405,712
Recurring | Managed investments | Fund of hedge funds
Investment [Line Items]
Other investments, at fair value		996	955
Recurring | Managed investments | Hedge funds
Investment [Line Items]
Other investments, at fair value		17,624	17,381
Recurring | Managed investments | Private equity investments
Investment [Line Items]
Other investments, at fair value		95,927	82,627
Recurring | Managed investments | Fixed income investment funds
Investment [Line Items]
Other investments, at fair value		269,113	249,275
Recurring | Managed investments | Overseas deposits
Investment [Line Items]
Other investments, at fair value		53,709	50,106
Recurring | Managed investments | Mutual funds
Investment [Line Items]
Other investments, at fair value		5,635	5,368
Recurring | Managed investments | Subject to redemption restriction
Investment [Line Items]
Other investments, at fair value		398,046	369,402
Recurring | Managed investments | Subject to redemption restriction | Fund of hedge funds
Investment [Line Items]
Other investments, at fair value		996	955
Recurring | Managed investments | Subject to redemption restriction | Hedge funds
Investment [Line Items]
Other investments, at fair value		17,624	17,381
Recurring | Managed investments | Subject to redemption restriction | Private equity investments
Investment [Line Items]
Other investments, at fair value		95,927	82,627
Recurring | Managed investments | Subject to redemption restriction | Fixed income investment funds
Investment [Line Items]
Other investments, at fair value		229,790	218,333
Recurring | Managed investments | Subject to redemption restriction | Overseas deposits
Investment [Line Items]
Other investments, at fair value		53,709	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		44,958	36,310
Recurring | Managed investments | Not subject to redemption restriction | Fund of hedge funds
Investment [Line Items]
Other investments, at fair value		0	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		$ 39,323	$ 30,942
Redemption frequency		Daily	Daily
Redemption notice period	[1]		2 days
Recurring | Managed investments | Not subject to redemption restriction | Fixed income investment funds | Minimum
Investment [Line Items]
Redemption notice period	[1]	1 day
Recurring | Managed investments | Not subject to redemption restriction | Fixed income investment funds | Maximum
Investment [Line Items]
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		$ 5,635	$ 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
		Mar. 31, 2017	Mar. 31, 2016
Schedule of Equity Method Investments [Line Items]
Investments in affiliates, beginning of period		$ 100,431
Income (loss) from investment affiliates		5,188	$ (4,113)
Investments in affiliates, end of period		94,697
Investment affiliate
Schedule of Equity Method Investments [Line Items]
Investments in affiliates, beginning of period		100,431	87,673
Net capital contributions		(10,922)	575
Income (loss) from investment affiliates		5,188	(4,113)
Investments in affiliates, end of period		94,697	$ 84,135
Managed investments
Schedule of Equity Method Investments [Line Items]
Investments in affiliates, beginning of period	[1],[2]	100,431
Investments in affiliates, end of period	[1],[2]	$ 94,697
[1]	In accordance with ASC Topic 825 “Financial Instruments,” the Company’s investments in investment affiliates have not been classified in the fair value hierarchy.
[2]	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 (Investment affil45

Investments (Investment affiliate details) (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Mar. 20, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Investments in investment affiliates, at cost		$ 73,918		$ 84,840
Investments in affiliates		94,697		100,431
Aquiline Financial Services Fund II LP
Schedule of Equity Method Investments [Line Items]
Remaining capital commitment		2,830		2,040
Aquiline Financial Services Fund III LP
Schedule of Equity Method Investments [Line Items]
Remaining capital commitment		62,031		62,031
Aquiline Tech
Schedule of Equity Method Investments [Line Items]
Remaining capital commitment		20,000	$ 20,000
Investment affiliate
Schedule of Equity Method Investments [Line Items]
Investments in investment affiliates, at cost		73,918
Investments in affiliates		94,697		100,431	$ 84,135	$ 87,673
Investment affiliate | Aquiline Financial Services Fund II LP
Schedule of Equity Method Investments [Line Items]
Investments in investment affiliates, at cost		$ 35,949		$ 46,871
Voting ownership %		0.00%		0.00%
Equity ownership %		8.10%		8.10%
Investments in affiliates		$ 54,524		$ 61,999
Investment affiliate | Aquiline Financial Services Fund III LP
Schedule of Equity Method Investments [Line Items]
Investments in investment affiliates, at cost		$ 37,969		$ 37,969
Voting ownership %		0.00%		0.00%
Equity ownership %		9.00%		9.00%
Investments in affiliates		$ 40,173		$ 38,432
Investment affiliate | Aquiline Tech
Schedule of Equity Method Investments [Line Items]
Investments in investment affiliates, at cost		$ 0
Voting ownership %		0.00%
Equity ownership %		16.40%
Investments in affiliates		$ 0
Managed investments
Schedule of Equity Method Investments [Line Items]
Investments in investment affiliates, at cost	[1]	73,918		84,840
Investments in affiliates	[1],[2]	$ 94,697		$ 100,431
[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 825 “Financial Instruments,” the Company’s investments in investment affiliates have not been classified in the fair value hierarchy.

Investments (Components of net

Investments (Components of net investment income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net investment income
Net investment income	$ 40,214	$ 29,461
Managed investments
Net investment income
Total gross investment income	39,164	29,759
Investment expenses	(2,972)	(1,836)
Net investment income	36,192	27,923
Managed investments | Fixed maturities and short term investments
Net investment income
Total gross investment income	31,671	28,017
Managed investments | Other investments
Net investment income
Total gross investment income	6,870	872
Managed investments | Restricted cash, cash and cash equivalents
Net investment income
Total gross investment income	610	865
Managed investments | Securities lending income
Net investment income
Total gross investment income	13	5
Non-managed investments
Net investment income
Net investment income	4,022	1,538
Non-managed investments | Fixed maturities and short term investments
Net investment income
Total gross investment income	3,060	1,295
Non-managed investments | Restricted cash, cash and cash equivalents
Net investment income
Total gross investment income	$ 962	$ 243

Investments (Realized and unrea

Investments (Realized and unrealized gains) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Fixed Maturities Short Term And Other Investments And Cash Equivalents [Abstract]
Net realized losses on investments	$ (1,164)	$ (584)
Change in net unrealized gains on investments	13,348	47,444
Total net realized and change in net unrealized gains (losses) on investments	12,184	46,860
Managed investments
Fixed Maturities Short Term And Other Investments And Cash Equivalents [Abstract]
Gross realized gains	2,690	3,217
Gross realized losses	(5,582)	(4,303)
Net realized losses on investments	(2,892)	(1,086)
Change in net unrealized gains on investments	14,349	47,078
Total net realized and change in net unrealized gains (losses) on investments	11,457	45,992
Non-managed investments
Fixed Maturities Short Term And Other Investments And Cash Equivalents [Abstract]
Gross realized gains	1,728	511
Gross realized losses	0	(9)
Net realized losses on investments	1,728	502
Change in net unrealized gains on investments	(1,001)	366
Total net realized and change in net unrealized gains (losses) on investments	$ 727	$ 868

Investments (Narrative) (Detail

Investments (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)funds	Dec. 31, 2016USD ($)
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other investments, at fair value	$ 443,004	$ 405,712
Cash, cash equivalents, restricted cash and investments pledged as collateral	5,173,735	5,173,966
Investments held in trust	5,105,855	5,068,092
Investments and cash pledged as collateral	$ 412,176	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	$ 443,004	405,712
Recurring | Managed investments
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other investments, at fair value	443,004	405,712
Recurring | Managed investments | Subject to redemption restriction
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other investments, at fair value	$ 398,046	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	$ 188,682	$ 184,749
Redemption restriction period	2 years

Fair value measurements (Fair v

Fair value measurements (Fair value hierarchy) (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		$ 5,365,216	$ 5,543,030
Short-term investments, at fair value		2,785,226	2,796,170
Other investments, at fair value		443,004	405,712
Investments in affiliates		94,697	100,431
Total investments		8,688,143	8,845,343
Managed investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		5,163,255	5,384,699
Short-term investments, at fair value		232,955	228,386
Other investments, at fair value		443,004	405,712
Investments in affiliates	[1],[2]	94,697	100,431
Total investments		5,933,911	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		718,025	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		258,463	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		229,129	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		653,395	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		19,382	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		1,486,882	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		397,989	410,227
Managed investments | Bank loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		567,012	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		514,690	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		318,288	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		996	955
Managed investments | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		17,624	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		95,927	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		269,113	249,275
Managed investments | Overseas deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		53,709	50,106
Managed investments | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		5,635	5,368
Non-managed investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		201,961	158,331
Short-term investments, at fair value		2,552,271	2,567,784
Total investments		2,754,232	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		201,961	158,331
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments		8,688,143	8,845,343
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments		2,767,130	2,777,435
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments		5,095,018	5,279,272
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments		345,812	330,970
Recurring | Managed investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value		5,163,255	5,384,699
Short-term investments, at fair value		232,955	228,386
Other investments, at fair value		443,004	405,712
Total investments		5,933,911	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		718,025	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		258,463	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		229,129	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		653,395	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		19,382	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		1,486,882	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		397,989	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		567,012	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		514,690	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		318,288	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		996	955
Recurring | Managed investments | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value		17,624	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		95,927	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		269,113	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		53,709	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		5,635	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		214,859	209,651
Other investments, at fair value		0	0
Total investments		214,859	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	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		4,902,679	5,114,272
Short-term investments, at fair value		18,096	18,735
Other investments, at fair value		44,958	36,309
Total investments		4,965,733	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		718,025	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		258,463	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		229,129	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		653,395	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		19,382	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		1,486,882	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		397,989	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		330,318	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		490,808	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		318,288	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	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		39,323	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		5,635	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		260,576	270,427
Short-term investments, at fair value		0	0
Other investments, at fair value		12,560	12,168
Total investments		273,136	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		236,694	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		23,882	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	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		12,560	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		2,552,271	2,567,784
Total investments		2,754,232	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		201,961	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		2,552,271	2,567,784
Total investments		2,552,271	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		129,285	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		129,285	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		72,676	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		72,676	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	[3]	385,486	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	[3]	0	0
Short-term investments, at fair value	[3]	0	0
Other investments, at fair value	[3]	385,486	357,235
Total investments	[3]	385,486	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	[3]	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	[3]	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	[3]	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	[3]	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	[3]	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	[3]	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	[3]	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	[3]	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	[3]	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	[3]	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	[3]	996	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	[3]	17,624	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	[3]	95,927	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	[3]	217,230	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	[3]	53,709	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	[3]	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	[3]	0	0
Total investments	[3]	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	[3]	$ 0	$ 0
[1]	In accordance with ASC Topic 825 “Financial Instruments,” the Company’s investments in investment affiliates have not been classified in the fair value hierarchy.
[2]	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.”
[3]	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
	Mar. 31, 2017	Mar. 31, 2016
Reconciliation of beginning and ending balances for all investments measured at fair value on recurring basis
Level 3 investments - beginning of period	$ 330,970	$ 245,837
Purchases	84,267	65,375
Sales		(2,389)
Settlements	(71,498)	(16,374)
Net realized losses	3,134
Change in net unrealized (losses) gains	(1,061)	(333)
Level 3 investments - end of period	345,812	292,116
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	246,496	232,337
Purchases	23,176	42,103
Sales		(2,389)
Settlements	(33,110)	(16,249)
Net realized losses	0
Change in net unrealized (losses) gains	132	(791)
Level 3 investments - end of period	236,694	255,011
Catastrophe bonds
Reconciliation of beginning and ending balances for all investments measured at fair value on recurring basis
Level 3 investments - beginning of period	48,375	13,500
Purchases	61,091	23,272
Sales		0
Settlements	(38,780)	(125)
Net realized losses	3,134
Change in net unrealized (losses) gains	(1,144)	458
Level 3 investments - end of period	72,676	$ 37,105
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	12,168
Purchases	0
Settlements	392
Net realized losses	0
Change in net unrealized (losses) gains	0
Level 3 investments - end of period	12,560
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	23,931
Purchases	0
Settlements	0
Net realized losses	0
Change in net unrealized (losses) gains	(49)
Level 3 investments - end of period	$ 23,882

Fair value measurements (Narrat

Fair value measurements (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Trading Securities	$ 8,688,143	$ 8,845,343
Managed investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Trading Securities	5,933,911	6,119,228
Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Trading Securities	$ 8,688,143	8,845,343
Recurring | Hedge fund side pocket
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	$ 5,933,911	6,119,228
Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Trading Securities	345,812	330,970
Recurring | Level 3 | Managed investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Trading Securities	$ 273,136	$ 282,595
Ratio of Level 3 investments to total investments (percent)	4.60%	4.60%

Variable interest entities (Not

Variable interest entities (Notes payable to AlphaCat investors) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Accounts payable and accrued expenses
Variable Interest Entity [Line Items]
Redemption of notes payable to AlphaCat investors		$ (1,000)
Variable interest entities, primary beneficiary
Variable Interest Entity [Line Items]
Notes payable to AlphaCat investors, beginning of period	$ 278,202	75,493
Issuance of notes payable to AlphaCat investors	377,330	406,037
Redemption of notes payable to AlphaCat investors	(208,956)	(204,038)
Foreign exchange gains	0	710
Notes payable to AlphaCat investors, end of period	446,576	278,202
Variable interest entities, primary beneficiary | Variable Funding Notes
Variable Interest Entity [Line Items]
Notes payable to AlphaCat investors, beginning of period	278,202	75,493
Issuance of notes payable to AlphaCat investors	274,010	311,711
Redemption of notes payable to AlphaCat investors	(208,956)	(109,712)
Foreign exchange gains	0	710
Notes payable to AlphaCat investors, end of period	343,256	278,202
Variable interest entities, primary beneficiary | Structured Notes
Variable Interest Entity [Line Items]
Notes payable to AlphaCat investors, beginning of period	0	0
Issuance of notes payable to AlphaCat investors	103,320	94,326
Redemption of notes payable to AlphaCat investors	0	(94,326)
Foreign exchange gains	0	0
Notes payable to AlphaCat investors, end of period	$ 103,320	$ 0

Variable interest entities (Ass

Variable interest entities (Assets and liabilities of consolidated VIEs) (Details) - Variable interest entities, primary beneficiary - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
AlphaCat sidecars
Variable Interest Entity [Line Items]
Total assets		$ 28,998	$ 40,041
Total liabilities		3,196	3,206
AlphaCat ILS funds - Lower Risk
Variable Interest Entity [Line Items]
Total assets	[1]	1,430,039	1,498,276
Total liabilities	[1]	41,699	42,457
AlphaCat ILS funds - Higher Risk
Variable Interest Entity [Line Items]
Total assets	[1]	866,386	972,633
Total liabilities	[1]	143,629	381,332
AlphaCat Re and AlphaCat Master Fund
Variable Interest Entity [Line Items]
Total assets		2,541,415	2,510,415
Total liabilities		2,541,245	2,510,245
BetaCat ILS funds
Variable Interest Entity [Line Items]
Total assets		88,656	82,471
Total liabilities		$ 219	$ 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		12 Months Ended
	Mar. 31, 2017USD ($)fundssubsidiaries	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)
Variable Interest Entity [Line Items]
(Income) attributable to AlphaCat investors	$ 7,503	$ 4,600
Accounts payable and accrued expenses
Variable Interest Entity [Line Items]
Variable Interest Entity Redemption Of Notes Payable To AlphaCat Investors			$ 1,000
(Income) attributable to AlphaCat investors	9,510	$ 17,068
Variable interest entities, primary beneficiary
Variable Interest Entity [Line Items]
Variable Interest Entity Redemption Of Notes Payable To AlphaCat Investors	$ 208,956		204,038
Variable funding notes, typical minimum duration	12 months
AlphaCat ILS funds
Variable Interest Entity [Line Items]
Number of AlphaCat ILS funds | funds	1
AlphaCat ILS funds | Variable interest entities, primary beneficiary
Variable Interest Entity [Line Items]
Risk profile percentage	7.00%
BetaCat ILS funds | Variable interest entities, primary beneficiary
Variable Interest Entity [Line Items]
Number of consolidated VIE BetaCat ILS funds | subsidiaries	2
Structured Notes
Variable Interest Entity [Line Items]
Structured notes interest rate percentage	8.00%
Structured Notes | Variable interest entities, primary beneficiary
Variable Interest Entity [Line Items]
Variable Interest Entity Redemption Of Notes Payable To AlphaCat Investors	$ 0		$ 94,326

Noncontrolling interest (Detail

Noncontrolling interest (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Noncontrolling Interest [Line Items]
Balance, beginning of period	$ 1,693,978	$ 1,266,376
Issuance of shares	258,679	381,075
Income attributable to noncontrolling interest	42,572	37,531
Redemption of shares	(7,002)	(118,722)
Balance, end of period	1,988,227	1,566,260
Redeemable noncontrolling interest
Noncontrolling Interest [Line Items]
Amounts Payable to Noncontrolling Interest	3,234		$ 71,530
Balance, beginning of period	1,528,001	1,111,714
Issuance of shares	103,699	268,750
Income attributable to noncontrolling interest	25,930	28,573
Redemption of shares	0	0
Balance, end of period	1,657,630	1,409,037
Noncontrolling interest
Noncontrolling Interest [Line Items]
Amounts Payable to Noncontrolling Interest	0		$ 16,144
Balance, beginning of period	165,977	154,662
Issuance of shares	154,980	112,325
Income attributable to noncontrolling interest	16,642	8,958
Distributions	(7,002)	(118,722)
Balance, end of period	$ 330,597	$ 157,223

Derivative instruments (Amount

Derivative instruments (Amount and balance sheet location) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Not designated as hedging instruments | Foreign exchange contracts
Summary of derivatives
Net Notional Exposure	$ 152,683	$ 181,375
Not designated as hedging instruments | Foreign exchange contracts | Other assets
Summary of derivatives
Fair value, derivative assets	1,475	2,351
Not designated as hedging instruments | Foreign exchange contracts | Accounts payable and accrued expenses
Summary of derivatives
Fair value, derivative liabilities	1,517	3,421
Designated as hedging instruments | Interest rate swap contracts
Summary of derivatives
Net Notional Exposure	552,563	552,263
Designated as hedging instruments | Interest rate swap contracts | Other assets
Summary of derivatives
Fair value, derivative assets	20	20
Designated as hedging instruments | Interest rate swap contracts | Accounts payable and accrued expenses
Summary of derivatives
Fair value, derivative liabilities	$ 1,314	$ 1,479

Derivative instruments (Amoun57

Derivative instruments (Amount included in statement of operations) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Not designated as hedging instruments | Foreign exchange gains (losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses) recognized in earnings	$ 453	$ (2,013)
Not designated as hedging instruments | Other income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses) recognized in earnings	(105)	36
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	97	(758)
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	2,160	3,656
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	$ (2,257)	$ (2,898)

Reserve for losses and loss e58

Reserve for losses and loss expenses (Components of reserves for losses and loss expenses) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Insurance Loss Reserves [Abstract]
Case reserves	$ 1,234,156	$ 1,237,772
IBNR	1,818,589	1,757,423
Reserve for losses and loss expenses	$ 3,052,745	$ 2,995,195	$ 2,980,300	$ 2,996,567

Reserve for losses and loss e59

Reserve for losses and loss expenses (Reserve rollforward) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Reserve for paid losses and unpaid loss expenses
Reserve for losses and loss expenses, beginning of period	$ 2,995,195	$ 2,996,567
Loss reserves recoverable, beginning of period	(430,421)	(350,586)
Net reserves for losses and loss expenses, beginning of period	2,564,774	2,645,981
Increase (decrease) in net losses and loss expenses incurred in respect of losses occurring in:
Current year	330,816	278,186
Prior years	(61,231)	(53,739)
Total incurred losses and loss expenses	269,585	224,447
Less net losses and loss expenses paid in respect of losses occurring in:
Current year	(7,698)	(15,774)
Prior years	(238,089)	(253,303)
Total net paid losses	(245,787)	(269,077)
Foreign exchange loss	12,317	8,260
Net reserve for losses and loss expenses, end of period	2,600,889	2,609,611
Loss reserves recoverable, end of period	451,856	370,689
Reserve for losses and loss expenses, end of period	3,052,745	2,980,300
Components of incurred losses and loss expenses
Gross losses and loss expenses	346,795	269,853
Reinsurance recoverable	(77,210)	(45,406)
Net incurred losses and loss expenses	$ 269,585	$ 224,447

Reserve for losses and loss e60

Reserve for losses and loss expenses (Prior year development) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	$ (61,231)	$ (53,739)
Validus Re
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(28,780)	(25,684)
Talbot
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(28,814)	(22,720)
Western World
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(219)	(4,426)
AlphaCat
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(3,418)	(909)
Property
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(17,123)	(41,900)
Property | Validus Re
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(3,571)	(22,832)
Property | Talbot
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(6,334)	(18,446)
Property | Western World
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(2,823)	(441)
Property | AlphaCat
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(4,395)	(181)
Marine
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(31,425)	6,519
Marine | Validus Re
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(15,429)	3,555
Marine | Talbot
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(15,996)	2,964
Specialty
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(15,287)	(14,373)
Specialty | Validus Re
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(9,780)	(6,407)
Specialty | Talbot
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	(6,484)	(7,238)
Specialty | AlphaCat
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	977	(728)
Liability
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	2,604	(3,985)
Liability | Western World
Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
Net favorable development on prior years	$ 2,604	$ (3,985)

Reinsurance (Components of rein

Reinsurance (Components of reinsurance) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Reinsurance Disclosures [Abstract]
Outstanding losses	$ 175,863	$ 165,328
IBNR	275,993	265,093
Total loss reserves recoverable	451,856	430,421	$ 370,689	$ 350,586
Paid losses recoverable	37,837	35,247
Total reinsurance balances recoverable	$ 489,693	$ 465,668

Reinsurance (Ceded credit risk)

Reinsurance (Ceded credit risk) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Ceded Credit Risk [Line Items]
Provision for uncollectible reinsurance relating to losses recoverable	$ 6,019	$ 5,153
Reinsurance Recoverable
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 489,693	$ 465,668
Percentage of total	100.00%	100.00%
Reinsurance Recoverable | A- or better
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 484,664	$ 461,369
Percentage of total	99.00%	99.10%
Reinsurance Recoverable | Top 10 reinsurers
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 401,038	$ 395,308
Percentage of total	81.90%	84.90%
Reinsurance Recoverable | Top 10 reinsurers | Lloyds Syndicates | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 79,547	$ 84,419
Percentage of total	16.20%	18.20%
Reinsurance Recoverable | Top 10 reinsurers | Swiss Re | AA- rating
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 77,143	$ 84,044
Percentage of total	15.80%	18.10%
Reinsurance Recoverable | Top 10 reinsurers | Fully collateralized reinsurers | NR
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 71,014	$ 83,088
Percentage of total	14.50%	17.80%
Reinsurance Recoverable | Top 10 reinsurers | Hannover Re | AA- rating
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 55,274	$ 50,603
Percentage of total	11.30%	10.90%
Reinsurance Recoverable | Top 10 reinsurers | Everest Re | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 48,829	$ 36,912
Percentage of total	10.00%	7.90%
Reinsurance Recoverable | Top 10 reinsurers | Munich Re | AA- rating
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 20,167	$ 18,214
Percentage of total	4.10%	3.90%
Reinsurance Recoverable | Top 10 reinsurers | Transatlantic Re | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 18,222	$ 10,593
Percentage of total	3.70%	2.30%
Reinsurance Recoverable | Top 10 reinsurers | XL Catlin | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 12,652
Percentage of total	2.60%
Reinsurance Recoverable | Top 10 reinsurers | Hamilton Re | A- rating
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 9,874	$ 10,343
Percentage of total	2.00%	2.20%
Reinsurance Recoverable | Top 10 reinsurers | Helvetia Group | A rating
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 8,316
Percentage of total	1.70%
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	$ 83,242	$ 66,944
Percentage of total	17.00%	14.40%
Reinsurance Recoverable | Other reinsurers' balances less than $1 million
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$ 5,413	$ 3,416
Percentage of total	1.10%	0.70%

Share capital (Common stock) (D

Share capital (Common stock) (Details) - USD ($) $ / shares in Units, $ in Thousands	Feb. 03, 2015	Mar. 31, 2017	Mar. 31, 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		80,508,849
Shares repurchased, cumulative	$ 2,274,401	$ 2,704,406
Remaining share repurchase authorization amount		$ 319,995
Summary of common shares issued and outstanding
Common shares issued, beginning balance		161,279,976	160,570,772
Common shares issued, ending balance		161,285,411	160,582,277
Treasury shares, ending balance		(82,147,821)	(79,026,791)
Common shares outstanding, ending balance		79,137,590	81,555,486
Restricted share awards
Summary of common shares issued and outstanding
Vested, net of shares withheld		3,440	9,566
Restricted share units
Summary of common shares issued and outstanding
Vested, net of shares withheld		1,995	1,939

Share capital (Preferred stock)

Share capital (Preferred stock) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Preferred shares - Shareholders' Equity
Preferred shares equivalent depositary shares number	6,000,000
Proportionate interest of Series A Preferred shares, per depositary share	0.10%
Preferred shares, shares issued	6,000	6,000
Preferred shares, shares outstanding	6,000	6,000
Preferred shares
Preferred shares - Shareholders' Equity
Preferred shares issued	6,000
Preferred shares, dividend rate, percentage	5.875%
Preferred stock, par or stated value per share	$ 0.175
Preferred stock, liquidation preference, value	$ 25,000
Depositary share equivalent
Preferred shares - Shareholders' Equity
Preferred stock, liquidation preference, value	$ 25

Share capital (Dividends) (Deta

Share capital (Dividends) (Details) - $ / shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Class of Stock [Line Items]
Cash dividends declared per share - common shares	$ 0.38	$ 0.35
Depositary share equivalent
Class of Stock [Line Items]
Cash dividends declared per share - preferred shares	$ 0.3671875

Stock plans (Options activity)

Stock plans (Options activity) (Details) - $ / shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Options activities:
Options outstanding, beginning balance (in shares)	26,136	65,401
Options exercised during period (in shares)	0	0
Options outstanding, ending balance (in shares)	26,136	65,401
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	0
Weighted average grant date fair value, ending balance (in dollars per share)	6.78	7.74
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	0
Weighted average grant date exercise price, ending balance (in dollars per share)	$ 23.48	$ 20.17

Stock plans (Other awards activ

Stock plans (Other awards activity) (Details) - $ / shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Restricted share awards
Activities
Beginning balance (in shares)	2,469,982	2,739,446
Granted (in shares)	2,082	0
Vested (in shares)	(4,571)	(12,550)
Forfeited (in shares)	(513)	(8,317)
Ending balance (in shares)	2,466,980	2,718,579
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)	57.66	0
Weighted average grant date fair value, vested (in dollars per share)	37.93	35.75
Weighted average grant date fair value, forfeited (in dollars per share)	48.69	37.94
Weighted average grant date fair value, ending balance (in dollars per share)	$ 40.91	$ 38.26
Restricted share units
Activities
Beginning balance (in shares)	112,808	114,337
Vested (in shares)	(2,115)	(2,056)
Issued in lieu of cash dividends (in shares)	717	790
Ending balance (in shares)	111,410	113,071
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, vested (in dollars per share)	38.24	38.24
Weighted average grant date fair value, issued in lieu of cash dividends (in dollars per share)	40.95	38.47
Weighted average grant date fair value, ending balance (in dollars per share)	$ 41.01	$ 38.47
Performance shares
Activities
Beginning balance (in shares)	285,820	172,594
Conversion adjustment (in shares)	(26,322)	45,517
Ending balance (in shares)	259,498	218,111
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, conversion adjustment (in dollars per share)	36.82	36.82
Weighted average grant date fair value, ending balance (in dollars per share)	$ 45.26	$ 39.89

Stock plans (Components of shar

Stock plans (Components of share compensation expenses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Total share compensation expenses
Share compensation expenses	$ 9,491	$ 11,237
Restricted share awards
Total share compensation expenses
Share compensation expenses	9,044	9,129
Restricted share units
Total share compensation expenses
Share compensation expenses	315	311
Performance shares
Total share compensation expenses
Share compensation expenses	$ 132	$ 1,797

Stock plans (Narrative) (Detail

Stock plans (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Stock plans (other details)
Number of shares reserved for issuance under the LTIP and STIP	2,753,292
Remaining number of shares reserved for issuance	1,275,446
Share compensation expenses	$ 9,491	$ 11,237
Options exercised during period (in shares)	0	0
Share Based Compensation Arrangement By Share Based Payment Award Options Exercised In Period Weighted Average Grant Date Fair Value	$ 0	$ 0
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$ 0	$ 0
Options
Stock plans (other details)
Life of options	10 years
Restricted share awards
Stock plans (other details)
Share compensation expenses	$ 9,044	$ 9,129
Unrecognized share compensation expenses	$ 50,207		$ 58,804
Weighted average period of recognizing share based compensation expenses	2 years 1 month 17 days		2 years 3 months 3 days
Restricted share units
Stock plans (other details)
Share compensation expenses	$ 315	311
Unrecognized share compensation expenses	$ 2,241		$ 2,542
Weighted average period of recognizing share based compensation expenses	2 years 4 months 20 days		2 years 6 months 21 days
Performance shares
Stock plans (other details)
Share compensation expenses	$ 132	$ 1,797
Unrecognized share compensation expenses	$ 5,848		$ 6,902
Weighted average period of recognizing share based compensation expenses	1 year 10 months 20 days		2 years 21 days
Performance share awards performance period	3 years

Debt and financing arrangemen70

Debt and financing arrangements (Summary of outstanding debentures and senior notes payable) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Debt Instruments [Line Items]
Debentures payable	$ 537,402	$ 537,226
Debt instrument, commitment	250,000	250,000
Less: Unamortized debt issuance costs	(4,588)	(4,638)
Total senior notes payable	245,412	245,362
Debentures payable	782,814	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	133,852	133,676
Debt instrument, commitment	133,852
Flagstone 2007 Due July 30 2037
Debt Instruments [Line Items]
Debentures payable	113,750	$ 113,750
Debt instrument, commitment	$ 100,000

Debt and financing arrangemen71

Debt and financing arrangements (Credit facilities outstanding) (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Line of Credit Facility [Line Items]
Commitment		$ 670,000	$ 690,000
Drawn and outstanding		235,355	265,039
$85,000 syndicated unsecured letter of credit facility
Line of Credit Facility [Line Items]
Commitment		85,000	85,000
Drawn and outstanding		0	0
$300,000 syndicated secured letter of credit facility
Line of Credit Facility [Line Items]
Commitment		300,000	300,000
Drawn and outstanding		83,655	90,252
$24,000 secured bi-lateral letter of credit facility
Line of Credit Facility [Line Items]
Commitment		24,000	24,000
Drawn and outstanding		2,590	4,553
$20,000 AlphaCat Re secured letter of credit facility
Line of Credit Facility [Line Items]
Commitment	[1]	0	20,000
Drawn and outstanding	[1]	0	20,000
$25,000 IPC bi-lateral facility
Line of Credit Facility [Line Items]
Commitment		25,000	25,000
Drawn and outstanding		4,952	5,842
$236,000 Flagstone bi-lateral facility
Line of Credit Facility [Line Items]
Commitment		236,000	236,000
Drawn and outstanding		$ 144,158	$ 144,392
[1]	The Company terminated its AlphaCat Re secured letter of credit facility on January 6, 2017.

Debt and financing arrangemen72

Debt and financing arrangements (Summary of key terms of senior notes and debentures) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Debt Instruments [Line Items]
Commitment	$ 250,000	$ 250,000
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
Junior Subordinated Debt
Debt Instruments [Line Items]
Payments expected to be made after 2022	$ 537,402
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	$ 133,852
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
At Issuance | 2010 Senior Notes Due 2040
Debt Instruments [Line Items]
Fixed interest rate (in percent)	8.875%
At Issuance | 2006 Junior Subordinated
Debt Instruments [Line Items]
Fixed interest rate (in percent)	9.069%
At Issuance | Flagstone 2006 Junior Subordinated | Three month LIBOR
Debt Instruments [Line Items]
Spread on variable rate (in percent)	3.54%
At Issuance | 2007 Junior Subordinated
Debt Instruments [Line Items]
Fixed interest rate (in percent)	8.48%
At Issuance | Flagstone 2007 Due July 30 2037 | Three month LIBOR
Debt Instruments [Line Items]
Spread on variable rate (in percent)	3.00%
At Issuance | Flagstone 2007 Due September 15 2037 | Three month LIBOR
Debt Instruments [Line Items]
Spread on variable rate (in percent)	3.10%
Outstanding | 2010 Senior Notes Due 2040
Debt Instruments [Line Items]
Fixed interest rate (in percent)	8.875%
Outstanding | 2006 Junior Subordinated
Debt Instruments [Line Items]
Effective percentage	5.831%
Outstanding | Flagstone 2006 Junior Subordinated
Debt Instruments [Line Items]
Effective percentage	6.463%
Outstanding | 2007 Junior Subordinated
Debt Instruments [Line Items]
Effective percentage	5.18%
Outstanding | Flagstone 2007 Due July 30 2037
Debt Instruments [Line Items]
Effective percentage	5.90%
Outstanding | Flagstone 2007 Due September 15 2037
Debt Instruments [Line Items]
Effective percentage	5.983%

Debt and financing arrangemen73

Debt and financing arrangements (Investments pledged as collateral) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financial Instruments Owned and Pledged as Collateral [Line Items]
Investments and cash pledged as collateral	$ 412,176	$ 442,184
$300,000 syndicated secured letter of credit facility
Financial Instruments Owned and Pledged as Collateral [Line Items]
Investments and cash pledged as collateral	146,375	157,597
$24,000 secured bi-lateral letter of credit facility
Financial Instruments Owned and Pledged as Collateral [Line Items]
Investments and cash pledged as collateral	48,219	48,097
AlphaCat Re secured letter of credit facility (a)
Financial Instruments Owned and Pledged as Collateral [Line Items]
Investments and cash pledged as collateral	0	20,032
$236,000 Flagstone bi-lateral facility
Financial Instruments Owned and Pledged as Collateral [Line Items]
Investments and cash pledged as collateral	$ 217,582	$ 216,458

Debt and financing arrangemen74

Debt and financing arrangements (Components of finance expenses) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Debt Instruments [Line Items]
Finance expenses		$ 13,943	$ 15,203
2006 Junior Subordinated
Debt Instruments [Line Items]
Finance expenses		2,187	2,211
2007 Junior Subordinated
Debt Instruments [Line Items]
Finance expenses		1,810	1,831
Flagstone 2006 Junior Subordinated
Debt Instruments [Line Items]
Finance expenses		2,221	2,245
Flagstone 2007 Junior Subordinated
Debt Instruments [Line Items]
Finance expenses		1,723	1,767
2010 Senior Notes Due 2040
Debt Instruments [Line Items]
Finance expenses		5,597	5,597
Credit facilities
Debt Instruments [Line Items]
Finance expenses		218	661
Bank and other charges
Debt Instruments [Line Items]
Finance expenses		151	7
AlphaCat fees
Debt Instruments [Line Items]
Finance expenses	[1]	$ 36	$ 884
[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.

Accumulated other comprehensi75

Accumulated other comprehensive loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period, net of tax	$ 4,004,268
Balance, end of period, net of tax	4,242,473	$ 3,881,649
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period, net of tax	(23,216)	(12,569)
Net current period other comprehensive loss, net of tax	763	(2,869)
Balance, end of period, net of tax	(22,453)	(15,438)
Foreign currency translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period, net of tax	(22,274)	(11,834)
Net current period other comprehensive loss, net of tax	597	(2,028)
Balance, end of period, net of tax	(21,677)	(13,862)
Minimum pension liability
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period, net of tax	(150)	334
Net current period other comprehensive loss, net of tax	68	(83)
Balance, end of period, net of tax	(82)	251
Cash flow hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period, net of tax	(792)	(1,069)
Net current period other comprehensive loss, net of tax	98	(758)
Balance, end of period, net of tax	$ (694)	$ (1,827)

Commitments and contingencies76

Commitments and contingencies (Lloyd's syndicate) (Details) - 3 months ended Mar. 31, 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 $1.26	£1 equals $1.26
Maximum premium levies assessable, amount	$ 22,680
2017 Underwriting Year
Components Of Required Capital [Abstract]
Total	583,600
2016 Underwriting year
Components Of Required Capital [Abstract]
Total	$ 617,000

Commitments and contingencies77

Commitments and contingencies (Other investment commitments) (Details) - Investment commitment - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Other Commitments [Line Items]
Capital commitment		$ 308,000	$ 308,000
Remaining commitment		258,872	258,704
Investments in investment affiliates
Other Commitments [Line Items]
Remaining commitment	[1]	84,861	64,071
AlphaCat ILS funds
Other Commitments [Line Items]
Remaining commitment		8,000	10,000
Fixed maturity investments
Other Commitments [Line Items]
Remaining commitment		27,375	28,499
Other investments
Other Commitments [Line Items]
Remaining commitment	[2]	$ 138,636	$ 156,134
[1]	Refer to Note 3(c), “Investments in Investment Affiliates.”
[2]	The Company’s total capital commitments related to other investments as at both March 31, 2017 and December 31, 2016 was $308,000.

Related party transactions (Det

Related party transactions (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Investments in affiliates		$ 94,697		$ 100,431
Group Ark Insurance Holdings Ltd
Related Party Transaction [Line Items]
Gross premiums written			$ 1,906
Premiums receivable				292
Reinsurance premiums ceded			17
Loss reserves recoverable				798
Earned premium adjustments			526
Wellington Insurance Company
Related Party Transaction [Line Items]
Gross premiums written		2,974	0
Premiums receivable		2,676		666
Earned premium adjustments		861	0
Investment affiliate
Related Party Transaction [Line Items]
Investments in affiliates		94,697		100,431
Partnership fees incurred		356	$ 0
Investment commitment
Related Party Transaction [Line Items]
Remaining commitment		258,872		258,704
Investment commitment | Investment affiliate
Related Party Transaction [Line Items]
Remaining commitment	[1]	$ 84,861		$ 64,071
[1]	Refer to Note 3(c), “Investments in Investment Affiliates.”

Earnings per share (Details)

Earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Basic earnings per share
Net income available to Validus common shareholders	$ 94,561	$ 166,810
Weighted average number of common shares outstanding	79,133,671	82,821,261
Basic earnings per share available to common shareholders	$ 1.19	$ 2.01
Earnings per diluted share
Net income available to Validus common shareholders	$ 94,561	$ 166,810
Weighted average number of common shares outstanding	79,133,671	82,821,261
Weighted average number of diluted common shares outstanding	80,739,142	84,198,315
Earnings per diluted share available to common shareholders	$ 1.17	$ 1.98
Other details:
Anti-dilutive securities excluded from the calculation of diluted earnings per share	1,503
Stock options
Earnings per diluted share
Share equivalents	15,379	35,878
Unvested restricted shares
Earnings per diluted share
Share equivalents	1,590,092	1,341,176

Segment information (Summary of

Segment information (Summary of results of operating and other segments) (Details) $ in Thousands		3 Months Ended
		Mar. 31, 2017USD ($)segments	Mar. 31, 2016USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segments		4
Underwriting revenues
Gross premiums written		$ 1,190,857	$ 1,172,791
Reinsurance premiums ceded		(200,106)	(167,835)
Net premiums written		990,751	1,004,956
Change in unearned premiums		(415,375)	(433,688)
Net premiums earned		575,376	571,268
Other insurance related income (loss)		1,236	736
Segmental revenues		576,612	572,004
Underwriting deductions
Losses and loss expenses		269,585	224,447
Policy acquisition costs		111,628	107,193
General and administrative expenses		87,924	86,208
Share compensation expenses		9,491	11,237
Total underwriting deductions		478,628	429,085
Segmental income		97,984	142,919
Other items	[1]	8,641	36,561
Dividends on preferred shares		(2,203)	0
Net investment income		40,214	29,461
(Income) attributable to AlphaCat investors		(7,503)	(4,600)
Net (income) attributable to noncontrolling interest		(42,572)	(37,531)
Finance expenses		13,943	15,203
Tax (benefit) expense		(3,549)	(2,118)
Net realized gains on investments		(1,164)	(584)
Change in net unrealized gains on managed investments (a)		13,348	47,444
Income (loss) from investment affiliates		5,188	(4,113)
Foreign exchange gains (losses)		(1,569)	(6,245)
Net income available to Validus		96,764	166,810
Selected ratios:
Net income available to Validus common shareholders		94,561	166,810
Corporate and investment
Underwriting deductions
General and administrative expenses		17,177	16,183
Share compensation expenses		3,413	4,092
Total underwriting deductions		20,590	20,275
Segmental income		(20,590)	(20,275)
Other items	[1]	7,526	36,407
Dividends on preferred shares		(2,203)	0
Net investment income	[2]	36,192	27,923
Finance expenses	[2]	13,864	14,341
Tax (benefit) expense		(3,548)	(2,118)
Total expenses		33,109	32,498
Validus share of segmental income		20,925	44,055
Net realized gains on investments	[2]	(2,892)	(1,086)
Change in net unrealized gains on managed investments (a)	[2]	14,349	47,078
Income (loss) from investment affiliates		5,188	(4,113)
Foreign exchange gains (losses)	[2]	(1,103)	(6,074)
Other income		94	677
Total other items		17,842	48,630
Operating Segments | Validus Re
Underwriting revenues
Gross premiums written		620,522	691,668
Reinsurance premiums ceded		(108,813)	(92,495)
Net premiums written		511,709	599,173
Change in unearned premiums		(293,297)	(355,342)
Net premiums earned		218,412	243,831
Other insurance related income (loss)		78	(315)
Segmental revenues		218,490	243,516
Underwriting deductions
Losses and loss expenses		86,154	82,868
Policy acquisition costs		41,256	42,259
General and administrative expenses		16,832	17,179
Share compensation expenses		2,477	2,901
Total underwriting deductions		146,719	145,207
Segmental income		71,771	98,309
Validus share of segmental income		$ 71,771	$ 98,309
Selected ratios:
Net premiums written / Gross premiums written		82.50%	86.60%
Losses and loss expenses		39.40%	34.00%
Policy acquisition costs		18.90%	17.40%
General and administrative expenses	[3]	8.90%	8.20%
Expense ratio		27.80%	25.60%
Combined ratio		67.20%	59.60%
Operating Segments | Talbot Segment
Underwriting revenues
Gross premiums written		$ 247,175	$ 266,317
Reinsurance premiums ceded		(92,824)	(87,458)
Net premiums written		154,351	178,859
Change in unearned premiums		40,714	27,933
Net premiums earned		195,065	206,792
Other insurance related income (loss)		755	11
Segmental revenues		195,820	206,803
Underwriting deductions
Losses and loss expenses		106,412	100,101
Policy acquisition costs		43,276	44,343
General and administrative expenses		38,443	38,535
Share compensation expenses		2,827	3,522
Total underwriting deductions		190,958	186,501
Segmental income		4,862	20,302
Validus share of segmental income		$ 4,862	$ 20,302
Selected ratios:
Net premiums written / Gross premiums written		62.40%	67.20%
Losses and loss expenses		54.60%	48.40%
Policy acquisition costs		22.20%	21.50%
General and administrative expenses	[3]	21.10%	20.30%
Expense ratio		43.30%	41.80%
Combined ratio		97.90%	90.20%
Operating Segments | Western World
Underwriting revenues
Gross premiums written		$ 172,043	$ 63,959
Reinsurance premiums ceded		(5,618)	(4,139)
Net premiums written		166,425	59,820
Change in unearned premiums		(69,153)	1,679
Net premiums earned		97,272	61,499
Other insurance related income (loss)		241	288
Segmental revenues		97,513	61,787
Underwriting deductions
Losses and loss expenses		74,925	39,646
Policy acquisition costs		20,236	14,200
General and administrative expenses		10,754	12,075
Share compensation expenses		692	581
Total underwriting deductions		106,607	66,502
Segmental income		(9,094)	(4,715)
Validus share of segmental income		$ (9,094)	$ (4,715)
Selected ratios:
Net premiums written / Gross premiums written		96.70%	93.50%
Losses and loss expenses		77.00%	64.50%
Policy acquisition costs		20.80%	23.10%
General and administrative expenses	[3]	11.80%	20.50%
Expense ratio		32.60%	43.60%
Combined ratio		109.60%	108.10%
Operating Segments | AlphaCat
Underwriting revenues
Gross premiums written		$ 164,926	$ 167,348
Third party management fees		4,644	4,727
Related party management fees		631	891
Segmental revenues		5,275	5,618
Underwriting deductions
General and administrative expenses		3,844	1,482
Share compensation expenses		82	141
Total underwriting deductions		3,955	2,439
Segmental income		1,320	3,179
Net investment income	[4]	4,812	5,607
Finance expenses		31	808
Tax (benefit) expense		(1)	0
Foreign exchange gains (losses)		(1)	8
Operating Segments | AlphaCat | AlphaCat sidecars
Underwriting revenues
Gross premiums written		66	(52)
Underwriting deductions
Net investment income	[4]	(112)	124
Operating Segments | AlphaCat | AlphaCat ILS funds - Lower Risk
Underwriting revenues
Gross premiums written	[5]	52,908	59,958
Underwriting deductions
Net investment income	[4],[5]	2,189	2,507
Operating Segments | AlphaCat | AlphaCat ILS funds - Higher Risk
Underwriting revenues
Gross premiums written	[5]	93,536	96,320
Underwriting deductions
Net investment income	[4],[5]	2,367	2,436
Operating Segments | AlphaCat | BetaCat ILS funds
Underwriting deductions
Net investment income	[4]	368	563
Operating Segments | AlphaCat | PaCRe funds
Underwriting deductions
Net investment income	[4]	0	(23)
Operating Segments | AlphaCat | AlphaCat direct
Underwriting revenues
Gross premiums written	[6]	18,416	11,122
Operating Segments | AlphaCat And Consolidated Variable Interest Entities
Underwriting revenues
Gross premiums written		164,926	167,348
Reinsurance premiums ceded		(6,660)	(244)
Net premiums written		158,266	167,104
Change in unearned premiums		(93,639)	(107,958)
Net premiums earned		64,627	59,146
Other insurance related income (loss)		5,161	5,665
Segmental revenues		69,788	64,811
Underwriting deductions
Losses and loss expenses		2,094	1,832
Policy acquisition costs		6,901	6,157
General and administrative expenses		9,641	7,456
Share compensation expenses		82	141
Total underwriting deductions		18,718	15,586
Segmental income		51,070	49,225
Other items	[1]	1,115	154
Net investment income		4,022	1,538
(Income) attributable to AlphaCat investors		(7,503)	(4,600)
Net (income) attributable to noncontrolling interest		(42,572)	(37,531)
Validus share of segmental income		6,132	8,786
Eliminations
Underwriting revenues
Gross premiums written		(13,809)	(16,501)
Reinsurance premiums ceded		13,809	16,501
Other insurance related income (loss)		(4,999)	(4,913)
Segmental revenues		(4,999)	(4,913)
Underwriting deductions
Policy acquisition costs		(41)	234
General and administrative expenses		(4,923)	(5,220)
Total underwriting deductions		(4,964)	(4,986)
Segmental income		(35)	73
Net investment income		0
Validus share of segmental income		$ (35)	$ 73
[1]	Other items includes finance expenses, tax expenses, foreign exchange gains (losses), net realized and change in net unrealized gains (losses) on investments, income from investment and operating affiliates and other income (loss).
[2]	These items exclude the components which are included in Validus’ share of AlphaCat and amounts which are consolidated from VIEs.
[3]	The general and administrative expense ratio includes share compensation expenses.
[4]	The investment 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.

Segment information (Gross prem

Segment information (Gross premiums written by geographic location and segment) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 1,190,857	$ 1,172,791
Percent of gross premiums written		100.00%	100.00%
United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 442,319	$ 409,716
Percent of gross premiums written		37.10%	35.00%
Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	$ 74,781	$ 81,304
Percent of gross premiums written	[1]	6.30%	6.90%
Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 3,963	$ 11,183
Percent of gross premiums written		0.30%	1.00%
Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 41,092	$ 38,855
Percent of gross premiums written		3.50%	3.30%
Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 30,647	$ 34,363
Percent of gross premiums written		2.60%	2.90%
Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 4,149	$ 2,965
Percent of gross premiums written		0.30%	0.30%
Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 2,807	$ 2,717
Percent of gross premiums written		0.20%	0.20%
Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[2]	$ 35,495	$ 42,287
Percent of gross premiums written	[2]	3.00%	3.60%
Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 192,934	$ 213,674
Percent of gross premiums written		16.20%	18.20%
Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	$ 246,297	$ 246,770
Percent of gross premiums written	[1]	20.70%	21.00%
Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[3]	$ 309,307	$ 302,631
Percent of gross premiums written	[3]	26.00%	25.80%
Operating Segments | Validus Re
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 620,522	$ 691,668
Operating Segments | Validus Re | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		213,868	295,394
Operating Segments | Validus Re | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	34,068	30,264
Operating Segments | Validus Re | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		931	4,923
Operating Segments | Validus Re | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		29,616	22,467
Operating Segments | Validus Re | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		9,342	13,582
Operating Segments | Validus Re | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		1,161	872
Operating Segments | Validus Re | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		1,715	1,676
Operating Segments | Validus Re | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[2]	13,905	16,688
Operating Segments | Validus Re | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		90,738	90,472
Operating Segments | Validus Re | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	102,421	111,777
Operating Segments | Validus Re | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[3]	213,495	194,025
Operating Segments | Talbot Segment
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		247,175	266,317
Operating Segments | Talbot Segment | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		29,085	26,110
Operating Segments | Talbot Segment | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	34,331	35,504
Operating Segments | Talbot Segment | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		3,182	2,312
Operating Segments | Talbot Segment | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		11,715	13,861
Operating Segments | Talbot Segment | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		24,177	23,807
Operating Segments | Talbot Segment | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		1,825	617
Operating Segments | Talbot Segment | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		1,137	1,092
Operating Segments | Talbot Segment | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[2]	23,272	27,484
Operating Segments | Talbot Segment | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		99,639	104,677
Operating Segments | Talbot Segment | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	27,357	28,454
Operating Segments | Talbot Segment | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[3]	91,094	107,076
Operating Segments | Western World
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		172,043	63,959
Operating Segments | Western World | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		172,043	63,959
Operating Segments | Western World | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[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
Operating Segments | Western World | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		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
Operating Segments | Western World | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	0
Operating Segments | Western World | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	0
Operating Segments | Western World | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[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
Operating Segments | Western World | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	0	0
Operating Segments | Western World | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[3]	0	0
Operating Segments | AlphaCat
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		164,926	167,348
Operating Segments | AlphaCat | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		28,203	25,391
Operating Segments | AlphaCat | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	7,035	16,011
Operating Segments | AlphaCat | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	4,082
Operating Segments | AlphaCat | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		466	3,451
Operating Segments | AlphaCat | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	0
Operating Segments | AlphaCat | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		1,193	1,500
Operating Segments | AlphaCat | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	0
Operating Segments | AlphaCat | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[2]	0	0
Operating Segments | AlphaCat | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		8,694	25,044
Operating Segments | AlphaCat | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	123,309	115,373
Operating Segments | AlphaCat | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[3]	4,720	1,540
Eliminations
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(13,809)	(16,501)
Eliminations | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(880)	(1,138)
Eliminations | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	(653)	(475)
Eliminations | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(150)	(134)
Eliminations | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(705)	(924)
Eliminations | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(2,872)	(3,026)
Eliminations | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(30)	(24)
Eliminations | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(45)	(51)
Eliminations | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[2]	(1,682)	(1,885)
Eliminations | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(6,137)	(6,519)
Eliminations | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	(6,790)	(8,834)
Eliminations | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[3]	$ (2)	$ (10)
[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 (Details)

Subsequent events (Details) - Subsequent Event - ADM Crop Risk Services $ in Thousands	May 01, 2017USD ($)
Subsequent Event [Line Items]
Cost of acquisition	$ 127,500
Percentage of voting interests acquired	100.00%