Segment information (Summary of results of operating and other segments) (Details) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) segments	Sep. 30, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segments				4
Underwriting revenues
Gross premiums written		$ 372,418	$ 402,509	$ 2,309,251	$ 2,247,901
Reinsurance premiums ceded		(45,006)	(48,810)	(249,070)	(295,553)
Net premiums written		327,412	353,699	2,060,181	1,952,348
Change in unearned premiums		236,363	201,312	(351,415)	(248,759)
Net premiums earned		563,775	555,011	1,708,766	1,703,589
Other insurance related income (loss)		919	3,496	2,400	5,144
Segmental revenues		564,694	558,507	1,711,166	1,708,733
Underwriting deductions
Losses and loss expenses	[1]	258,394	256,010	789,971	763,085
Policy acquisition costs		113,434	105,039	328,593	307,773
General and administrative expenses		82,443	96,886	258,339	265,146
Share compensation expenses		10,501	9,983	32,465	28,279
Total underwriting deductions		464,772	467,918	1,409,368	1,364,283
Segmental income		99,922	90,589	301,798	344,450
Other items	[2]	(8,337)	(27,844)	52,280	(66,405)
Dividends on preferred shares		(2,252)	0	(2,252)	0
Net investment income		43,514	31,572	112,232	96,212
(Income) attributable to AlphaCat investors		(5,564)	(1,438)	(16,278)	(1,438)
Net (income) attributable to noncontrolling interest		(37,439)	(26,229)	(96,163)	(66,968)
Finance expenses		14,521	18,512	43,890	58,161
Tax (benefit) expense		1,830	2,018	1,418	7,132
Net realized gains on investments		4,397	(1,187)	6,537	5,226
Change in net unrealized gains on investments (a)		5,459	3,916	84,331	2,467
Income (loss) from investment affiliate		453	2,482	(4,249)	5,542
Foreign exchange gains (losses)		766	2,592	(11,765)	9,528
Net income available to Validus		92,096	66,650	353,869	305,851
Selected ratios:
Net income available to Validus common shareholders		89,844	66,650	351,617	305,851
Corporate and investment
Underwriting deductions
General and administrative expenses		18,221	18,804	52,276	51,502
Share compensation expenses		4,048	3,383	12,147	9,454
Total underwriting deductions		22,269	22,187	64,423	60,956
Segmental income		(22,269)	(22,187)	(64,423)	(60,956)
Other items	[2]	(9,558)	(18,448)	49,847	(51,256)
Dividends on preferred shares		(2,252)	0	(2,252)	0
Net investment income	[3]	41,071	29,991	105,843	91,281
Finance expenses	[3]	14,317	15,143	42,637	45,623
Tax (benefit) expense		1,830	2,018	1,418	7,132
Total expenses		40,668	39,348	110,730	113,711
Validus share of segmental income		6,992	(10,644)	89,015	(20,931)
Net realized gains on investments	[3]	4,080	(1,233)	5,514	5,051
Change in net unrealized gains on investments (a)	[3]	4,652	1,765	81,782	2,508
Income (loss) from investment affiliate		453	2,482	(4,249)	5,542
Foreign exchange gains (losses)	[3]	1,067	2,331	(11,628)	9,024
Other income		(1,529)	(1,970)	(773)	(2,578)
Total other items		6,589	(1,287)	93,902	1,499
Operating Segments | Validus Re
Underwriting revenues
Gross premiums written		94,741	103,297	1,072,219	1,112,410
Reinsurance premiums ceded		(15,967)	(15,846)	(111,658)	(149,001)
Net premiums written		78,774	87,451	960,561	963,409
Change in unearned premiums		149,705	153,210	(241,129)	(205,110)
Net premiums earned		228,479	240,661	719,432	758,299
Other insurance related income (loss)		58	2,569	(107)	3,318
Segmental revenues		228,537	243,230	719,325	761,617
Underwriting deductions
Losses and loss expenses		98,425	120,958	313,432	357,491
Policy acquisition costs		42,837	42,989	127,660	128,909
General and administrative expenses		17,528	19,964	52,579	58,254
Share compensation expenses		2,695	2,691	8,371	7,665
Total underwriting deductions		161,485	186,602	502,042	552,319
Segmental income		67,052	56,628	217,283	209,298
Validus share of segmental income		$ 67,052	$ 56,628	$ 217,283	$ 209,298
Selected ratios:
Net premiums written / Gross premiums written		83.10%	84.70%	89.60%	86.60%
Losses and loss expenses		43.10%	50.30%	43.60%	47.10%
Policy acquisition costs		18.70%	17.90%	17.70%	17.00%
General and administrative expenses	[4]	8.90%	9.40%	8.50%	8.70%
Expense ratio		27.60%	27.30%	26.20%	25.70%
Combined ratio		70.70%	77.60%	69.80%	72.80%
Operating Segments | Talbot Segment
Underwriting revenues
Gross premiums written		$ 189,674	$ 226,025	$ 752,058	$ 789,148
Reinsurance premiums ceded		(22,877)	(35,823)	(137,496)	(164,144)
Net premiums written		166,797	190,202	614,562	625,004
Change in unearned premiums		32,258	15,942	(7,166)	9,167
Net premiums earned		199,055	206,144	607,396	634,171
Other insurance related income (loss)		99	470	389	564
Segmental revenues		199,154	206,614	607,785	634,735
Underwriting deductions
Losses and loss expenses		109,860	94,414	319,271	268,512
Policy acquisition costs		46,488	44,575	134,444	141,338
General and administrative expenses		32,333	43,292	109,929	115,341
Share compensation expenses		3,163	3,214	9,955	9,195
Total underwriting deductions		191,844	185,495	573,599	534,386
Segmental income		7,310	21,119	34,186	100,349
Validus share of segmental income		$ 7,310	$ 21,119	$ 34,186	$ 100,349
Selected ratios:
Net premiums written / Gross premiums written		87.90%	84.20%	81.70%	79.20%
Losses and loss expenses		55.20%	45.80%	52.60%	42.40%
Policy acquisition costs		23.40%	21.60%	22.10%	22.30%
General and administrative expenses	[4]	17.80%	22.60%	19.70%	19.60%
Expense ratio		41.20%	44.20%	41.80%	41.90%
Combined ratio		96.40%	90.00%	94.40%	84.30%
Operating Segments | Western World
Underwriting revenues
Gross premiums written		$ 85,260	$ 70,871	$ 236,190	$ 207,372
Reinsurance premiums ceded		(6,202)	(4,716)	(15,347)	(13,390)
Net premiums written		79,058	66,155	220,843	193,982
Change in unearned premiums		(8,260)	(2,225)	(22,890)	2,948
Net premiums earned		70,798	63,930	197,953	196,930
Other insurance related income (loss)		219	248	696	787
Segmental revenues		71,017	64,178	198,649	197,717
Underwriting deductions
Losses and loss expenses		45,748	40,810	129,623	138,098
Policy acquisition costs		17,094	13,214	46,704	27,110
General and administrative expenses		10,171	9,587	33,704	29,137
Share compensation expenses		702	554	1,825	1,525
Total underwriting deductions		73,715	64,165	211,856	195,870
Segmental income		(2,698)	13	(13,207)	1,847
Validus share of segmental income		$ (2,698)	$ 13	$ (13,207)	$ 1,847
Selected ratios:
Net premiums written / Gross premiums written		92.70%	93.30%	93.50%	93.50%
Losses and loss expenses		64.60%	63.80%	65.50%	70.10%
Policy acquisition costs		24.10%	20.70%	23.60%	13.80%
General and administrative expenses	[4]	15.40%	15.90%	17.90%	15.60%
Expense ratio		39.50%	36.60%	41.50%	29.40%
Combined ratio		104.10%	100.40%	107.00%	99.50%
Operating Segments | AlphaCat
Underwriting revenues
Gross premiums written	[5]	$ 4,413	$ 9,891	$ 270,666	$ 174,491
Third party management fees	[5]	7,025	5,762	14,843	14,622
Related party management fees	[5]	1,373	1,738	2,592	4,058
Segmental revenues	[5]	8,398	7,500	17,435	18,680
Underwriting deductions
General and administrative expenses	[5]	3,324	4,124	7,557	8,883
Share compensation expenses	[5]	(107)	141	167	440
Total underwriting deductions	[5]	3,253	6,551	8,655	18,573
Segmental income	[5]	5,145	949	8,780	107
Net investment income	[5],[6]	6,031	(1,430)	16,059	14,948
Finance expenses	[5]	31	2,297	914	9,259
Foreign exchange gains (losses)	[5]	5	(11)	17	(9)
Operating Segments | AlphaCat | AlphaCat sidecars
Underwriting revenues
Gross premiums written	[5]	(112)	2,079	(178)	45,426
Underwriting deductions
Net investment income	[5],[6]	(72)	1,445	593	3,886
Operating Segments | AlphaCat | AlphaCat ILS funds - Lower Risk (a)
Underwriting revenues
Gross premiums written	[5],[7]	2,049	1,653	112,241	90,088
Underwriting deductions
Net investment income	[5],[6],[7]	2,321	2,274	6,903	5,454
Operating Segments | AlphaCat | AlphaCat ILS funds - Higher Risk (a)
Underwriting revenues
Gross premiums written	[5],[7]	1,797	1,374	140,127	34,192
Underwriting deductions
Net investment income	[5],[6],[7]	2,479	1,807	5,607	6,608
Operating Segments | AlphaCat | BetaCat ILS funds
Underwriting deductions
Net investment income	[5],[6]	1,303	1,007	2,979	1,241
Operating Segments | AlphaCat | PaCRe funds
Underwriting deductions
Net investment income	[5],[6]	0	(7,963)	(23)	(2,241)
Operating Segments | AlphaCat | AlphaCat direct
Underwriting revenues
Gross premiums written	[5],[8]	679	4,785	18,476	4,785
Operating Segments | AlphaCat And Consolidated Variable Interest Entities
Underwriting revenues
Gross premiums written		4,413	9,891	270,666	174,491
Reinsurance premiums ceded		(1,630)	0	(6,451)	(4,538)
Net premiums written		2,783	9,891	264,215	169,953
Change in unearned premiums		62,660	34,385	(80,230)	(55,764)
Net premiums earned		65,443	44,276	183,985	114,189
Other insurance related income (loss)		8,656	7,719	17,722	19,175
Segmental revenues		74,099	51,995	201,707	133,364
Underwriting deductions
Losses and loss expenses		4,361	(172)	27,645	(1,016)
Policy acquisition costs		7,075	4,606	19,762	11,783
General and administrative expenses		12,255	12,419	26,272	28,478
Share compensation expenses		(107)	141	167	440
Total underwriting deductions		23,584	16,994	73,846	39,685
Segmental income		50,515	35,001	127,861	93,679
Other items	[2]	1,221	(9,396)	2,433	(15,149)
Net investment income		2,443	1,581	6,986	4,931
(Income) attributable to AlphaCat investors		(5,564)	(1,438)	(16,278)	(1,438)
Net (income) attributable to noncontrolling interest		(37,439)	(26,229)	(96,163)	(66,968)
Validus share of segmental income	[5]	11,176	(481)	24,839	15,055
Eliminations
Underwriting revenues
Gross premiums written		(1,670)	(7,575)	(21,882)	(35,520)
Reinsurance premiums ceded		1,670	7,575	21,882	35,520
Other insurance related income (loss)		(8,113)	(7,510)	(16,300)	(18,700)
Segmental revenues		(8,113)	(7,510)	(16,300)	(18,700)
Underwriting deductions
Policy acquisition costs		(60)	(345)	23	(1,367)
General and administrative expenses		(8,065)	(7,180)	(16,421)	(17,566)
Total underwriting deductions		(8,125)	(7,525)	(16,398)	(18,933)
Segmental income		12	15	98	233
Net investment income		0		(597)
Validus share of segmental income		$ 12	$ 15	$ (499)	$ 233

[1] Upon closing the acquisition of Western World, an adjustment of $15,586 was made to increase net reserves to reflect fair value. This adjustment was amortized to income through a reduction in losses and loss expenses of $2,524 and $8,639, respectively, during the three and nine months ended September 30, 2015, benefiting the loss ratio by 3.9 and 4.4 percentage points, respectively. The remaining fair value adjustment of $2,340 was fully amortized during 2015.

[2] 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).

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

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

[5] 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

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

[7] 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.

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