Segment information (Details) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) segments	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segments										4
Underwriting income
Gross premiums written		$ 339,454	$ 372,418	$ 764,042	$ 1,172,791	$ 309,605	$ 402,509	$ 726,168	$ 1,119,224	$ 2,648,705	$ 2,557,506	$ 2,358,865
Reinsurance premiums ceded		(40,635)	(45,006)	(36,229)	(167,835)	(33,128)	(48,810)	(55,418)	(191,325)	(289,705)	(328,681)	(313,208)
Net premiums written		298,819	327,412	727,813	1,004,956	276,477	353,699	670,750	927,899	2,359,000	2,228,825	2,045,657
Change in unearned premiums		241,580	236,363	(154,090)	(433,688)	266,823	201,312	(98,062)	(352,009)	(109,835)	18,064	(52,602)
Net premiums earned		540,399	563,775	573,723	571,268	543,300	555,011	572,688	575,890	2,249,165	2,246,889	1,993,055
Other insurance related income (loss)										2,961	6,113	3,472
Segmental revenues										2,252,126	2,253,002	1,996,527
Underwriting deductions
Losses and loss expenses		275,126	258,394	307,130	224,447	214,748	256,010	266,146	240,929	1,065,097	977,833	765,015
Policy acquisition costs		120,889	113,434	107,966	107,193	102,285	105,039	104,323	98,411	449,482	410,058	339,467
General and administrative expenses		77,955	82,443	89,688	86,208	98,563	96,886	84,025	84,235	336,294	363,709	329,362
Share compensation expenses		10,442	10,501	10,727	11,237	10,062	9,983	9,242	9,054	42,907	38,341	33,073
Total segmental deductions										1,893,780	1,789,941	1,466,917
Segmental income										358,346	463,061	529,610
Other items	[1]									1,829	(120,616)	(66,757)
Dividends on preferred shares		(2,203)	(2,252)	0	0	0	0	0	0	(4,455)	0	0
Net investment income		38,153	43,514	39,257	29,461	31,612	31,572	33,611	31,029	150,385	127,824	100,086
(Income) attributable to AlphaCat investors		(7,080)	(5,564)	(6,114)	(4,600)	(974)	(1,438)	0	0	(23,358)	(2,412)	0
Net (income) attributable to noncontrolling interests		(27,200)	(37,439)	(21,193)	(37,531)	(25,996)	(26,229)	(22,561)	(18,178)	(123,363)	(92,964)	(74,880)
Finance expenses		14,630	14,521	14,166	15,203	16,581	18,512	18,682	20,967	58,520	74,742	68,324
Tax benefit (expense)		21,147	(1,830)	(1,706)	2,118	756	(2,018)	(2,549)	(2,565)	19,729	(6,376)	(155)
Net realized gains on investments		9,220	4,397	2,724	(584)	(2,928)	(1,187)	2,244	4,169	15,757	2,298	14,917
Change in net unrealized gains (losses) on managed investments (a)		(67,460)	5,459	31,428	47,444	(34,862)	3,916	(34,676)	33,227	16,871	(32,395)	(2,842)
(Loss) income from investment affiliates		2,166	453	(589)	(4,113)	(1,261)	2,482	284	2,776	(2,083)	4,281	8,411
Foreign exchange gains		(901)	(766)	6,286	6,245	797	(2,592)	(2,671)	(4,265)	10,864	(8,731)	(12,181)
Transaction expenses										0	0	(8,096)	[2]
Net income available to Validus common shareholders		$ 7,767	$ 89,844	$ 94,963	$ 166,810	$ 69,042	$ 66,650	$ 65,790	$ 173,411	359,384	374,893	479,963
Operating Segments | Validus Re
Underwriting income
Gross premiums written										1,111,054	1,126,759	1,118,532
Reinsurance premiums ceded										(111,564)	(149,088)	(163,678)
Net premiums written										999,490	977,671	954,854
Change in unearned premiums										(55,545)	12,542	(37,570)
Net premiums earned										943,945	990,213	917,284
Other insurance related income (loss)										(55)	3,575	3,159
Segmental revenues										943,890	993,788	920,443
Underwriting deductions
Losses and loss expenses										411,488	457,976	307,290
Policy acquisition costs										181,040	166,387	141,670
General and administrative expenses										72,770	78,428	74,739
Share compensation expenses										11,034	10,350	9,739
Total segmental deductions										676,332	713,141	533,438
Segmental income										267,558	280,647	387,005
Validus share of segmental income										$ 267,558	$ 280,647	$ 387,005
Selected ratios:
Ratio of net to gross premiums written										90.00%	86.80%	85.40%
Losses and loss expenses ratio										43.60%	46.20%	33.50%
Policy acquisition costs ratio										19.20%	16.80%	15.50%
General and administrative expenses ratio	[3]									8.80%	9.00%	9.20%
Expense ratio										28.00%	25.80%	24.70%
Combined ratio										71.60%	72.00%	58.20%
Operating Segments | Talbot
Underwriting income
Gross premiums written										$ 970,702	$ 1,018,835	$ 1,101,770
Reinsurance premiums ceded										(175,729)	(198,896)	(192,211)
Net premiums written										794,973	819,939	909,559
Change in unearned premiums										(13,057)	18,152	(29,785)
Net premiums earned										781,916	838,091	879,774
Other insurance related income (loss)										455	851	1,095
Segmental revenues										782,371	838,942	880,869
Underwriting deductions
Losses and loss expenses										424,946	347,322	423,394
Policy acquisition costs										177,127	187,535	187,162
General and administrative expenses										134,479	155,306	150,828
Share compensation expenses										13,078	12,373	11,346
Total segmental deductions										749,630	702,536	772,730
Segmental income										32,741	136,406	108,139
Validus share of segmental income										$ 32,741	$ 136,406	$ 108,139
Selected ratios:
Ratio of net to gross premiums written										81.90%	80.50%	82.60%
Losses and loss expenses ratio										54.30%	41.40%	48.10%
Policy acquisition costs ratio										22.70%	22.40%	21.30%
General and administrative expenses ratio	[3]									18.90%	20.00%	18.40%
Expense ratio										41.60%	42.40%	39.70%
Combined ratio										95.90%	83.80%	87.80%
Operating Segments | AlphaCat
Underwriting income
Gross premiums written	[4]									$ 270,402	$ 176,126	$ 126,785
Third party management fees	[4]									18,771	19,661	18,667
Related party management fees	[4]									3,329	5,309	7,467
Segmental revenues	[4]									22,100	24,970	26,134
Underwriting deductions
General and administrative expenses	[4]									10,233	12,115	10,134
Share compensation expenses	[4]									249	580	501
Total segmental deductions	[4]									11,538	21,991	14,032
Segmental income	[4]									10,562	2,979	12,102
Net investment income	[4],[5]									20,579	19,176	21,485
Finance expenses	[4]									947	9,312	3,417
Tax benefit (expense)										(90)	0	0
Foreign exchange gains	[4]									(19)	16	20
Operating Segments | AlphaCat | AlphaCat Re & Master Fund
Underwriting deductions
Net investment income	[4],[5]									0	0	(1,377)
Operating Segments | AlphaCat | AlphaCat Sidecars
Underwriting income
Gross premiums written	[4]									(341)	45,755	50,023
Underwriting deductions
Net investment income	[4],[5]									607	5,504	10,525
Operating Segments | AlphaCat | AlphaCat ILS Funds - Lower Risk
Underwriting income
Gross premiums written	[4],[6]									112,222	91,363	52,264
Underwriting deductions
Net investment income	[4],[5],[6]									8,901	7,491	7,974
Operating Segments | AlphaCat | AlphaCat ILS Funds - Higher Risk
Underwriting income
Gross premiums written	[4],[6]									140,022	34,228	24,498
Underwriting deductions
Net investment income	[4],[5],[6]									7,471	8,428	8,754
Operating Segments | AlphaCat | BetaCat ILS Funds
Underwriting deductions
Net investment income	[4],[5]									3,623	1,702	(51)
Operating Segments | AlphaCat | PaCRe
Underwriting deductions
Net investment income	[4],[5]									(23)	(3,949)	(4,340)
Operating Segments | AlphaCat | AlphaCat Direct
Underwriting income
Gross premiums written	[4]									18,499	4,780	0
Operating Segments | AlphaCat & Consolidated Variable Interest Entities
Underwriting income
Gross premiums written										270,402	176,126	126,785
Reinsurance premiums ceded										(6,451)	(4,538)	(4,348)
Net premiums written										263,951	171,588	122,437
Change in unearned premiums										(13,879)	(11,653)	564
Net premiums earned										250,072	159,935	123,001
Other insurance related income (loss)										22,386	25,524	25,750
Segmental revenues										272,458	185,459	148,751
Underwriting deductions
Losses and loss expenses										44,851	657	(16,704)
Policy acquisition costs										26,905	16,327	11,584
General and administrative expenses										34,333	39,055	36,298
Share compensation expenses										249	580	501
Total segmental deductions										106,338	56,619	31,679
Segmental income										166,120	128,840	117,072
Other items	[1]									2,478	(17,967)	(12,891)
Dividends on preferred shares											0
Net investment income										9,264	6,658	4,286
(Income) attributable to AlphaCat investors										(23,358)	(2,412)
Net (income) attributable to noncontrolling interests										(123,363)	(92,964)	74,880
Validus share of segmental income	[4]									31,141	22,155	33,587
Operating Segments | Western World Insurance Group, Inc
Underwriting income
Gross premiums written										323,220	278,504	65,235	[7]
Reinsurance premiums ceded										(22,634)	(18,877)	(6,428)	[7]
Net premiums written										300,586	259,627	58,807	[7]
Change in unearned premiums										(27,354)	(977)	14,189	[7]
Net premiums earned										273,232	258,650	72,996	[7]
Other insurance related income (loss)										912	1,044	264	[7]
Segmental revenues										274,144	259,694	73,260	[7]
Underwriting deductions
Losses and loss expenses										183,812	171,878	51,035	[7]
Policy acquisition costs										64,442	41,408	3,169	[7]
General and administrative expenses										43,280	38,715	11,121	[7]
Share compensation expenses										2,543	2,083	135	[7]
Total segmental deductions										294,077	254,084	65,460	[7]
Segmental income										(19,933)	5,610	7,800	[7]
Validus share of segmental income										$ (19,933)	$ 5,610	$ 7,800
Selected ratios:
Ratio of net to gross premiums written										93.00%	93.20%	90.10%	[7]
Losses and loss expenses ratio										67.30%	66.40%	69.90%	[7]
Policy acquisition costs ratio										23.50%	16.00%	4.40%	[7]
General and administrative expenses ratio	[3]									16.80%	15.80%	15.40%	[7]
Expense ratio										40.30%	31.80%	19.80%	[7]
Combined ratio										107.60%	98.20%	89.70%	[7]
Operating Segments | Corporate and Investment
Underwriting deductions
General and administrative expenses										$ 72,249	$ 75,724	$ 80,210
Share compensation expenses										16,003	12,955	11,352
Total segmental deductions										88,252	88,679	91,562
Segmental income										(88,252)	(88,679)	(91,562)
Other items	[1]									(649)	(102,649)	(53,866)
Dividends on preferred shares										(4,455)	0	0
Net investment income	[8]									141,718	121,166	95,800
(Income) attributable to AlphaCat investors										0
Net (income) attributable to noncontrolling interests										0		0
Finance expenses	[8]									57,183	61,071	60,309
Tax benefit (expense)	[8]									19,819	(6,376)	(155)
Total expenses										130,071	156,126	152,026
Validus share of segmental income										48,362	(70,162)	(57,724)
Net realized gains on investments	[8]									14,680	1,698	12,160
Change in net unrealized gains (losses) on managed investments (a)	[8]									14,106	(32,007)	(1,030)
(Loss) income from investment affiliates										(2,083)	4,281	8,411
Foreign exchange gains	[8]									10,778	(8,172)	(10,700)
Other income (loss)										(766)	(1,002)	(2,243)
Transaction expenses	[9]									0	0	(8,096)	[2]
Total other items										36,715	(35,202)	(1,498)
Eliminations
Underwriting income
Gross premiums written										(26,673)	(42,718)	(53,457)
Reinsurance premiums ceded										26,673	42,718	53,457
Net premiums written										0	0	0
Change in unearned premiums										0	0	0
Net premiums earned										0	0	0
Other insurance related income (loss)										(20,737)	(24,881)	(26,796)
Segmental revenues										(20,737)	(24,881)	(26,796)
Underwriting deductions
Losses and loss expenses										0	0	0
Policy acquisition costs										(32)	(1,599)	(4,118)
General and administrative expenses										(20,817)	(23,519)	(23,834)
Share compensation expenses										0	0	0
Total segmental deductions										(20,849)	(25,118)	(27,952)
Segmental income										112	237	1,156
Net investment income										(597)
Validus share of segmental income										$ (485)	$ 237	$ 1,156

[1] Other items includes finance expenses, tax (benefit) expense, 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] The transaction expenses relate to costs incurred in connection with the acquisition of Western World, which was completed on October 2, 2014. Transaction expenses are primarily comprised of legal, financial advisory and audit related services.

[3] The general and administrative expense ratio includes share compensation expenses.

[4] The results of AlphaCat are presented on an asset manager basis, which is non-GAAP. A reconciliation of Validus’ share of AlphaCat segment income to segmental income is presented in the tables below.

[5] The investment income from the AlphaCat funds and sidecars is based on equity accounting.

[6] AlphaCat Direct includes direct investments from third party investors in AlphaCat Re.

[7] The results of Western World have been included in the Company’s consolidated results from the October 2, 2014 date of acquisition.

[8] These items exclude the components which are included in Validus’ share of AlphaCat and amounts which are consolidated from VIEs.

[9] The transaction expenses relate to costs incurred in connection with the acquisition of Western World, which was completed on October 2, 2014. Transaction expenses are primarily comprised of legal, financial advisory and audit related services.