Segment information (Gross premiums written by geographic location and segment) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 372,418	$ 402,509	$ 2,309,251	$ 2,247,901
Percent of gross premiums written		100.00%	100.00%	100.00%	100.00%
United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 138,303	$ 131,494	$ 840,133	$ 881,172
Percent of gross premiums written		37.10%	32.60%	36.40%	39.20%
Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	$ 43,876	$ 36,091	$ 178,543	$ 155,625
Percent of gross premiums written	[1]	11.70%	9.00%	7.80%	6.90%
Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 3,301	$ 3,908	$ 19,361	$ 18,962
Percent of gross premiums written		0.90%	1.00%	0.80%	0.80%
Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 9,533	$ 13,895	$ 58,581	$ 80,318
Percent of gross premiums written		2.60%	3.50%	2.50%	3.60%
Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 41,416	$ 42,304	$ 106,857	$ 102,808
Percent of gross premiums written		11.10%	10.50%	4.60%	4.60%
Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 971	$ 1,055	$ 48,668	$ 45,449
Percent of gross premiums written		0.30%	0.30%	2.10%	2.00%
Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 2,122	$ 1,669	$ 9,317	$ 8,812
Percent of gross premiums written		0.60%	0.40%	0.40%	0.40%
Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[2]	$ 21,592	$ 30,502	$ 96,487	$ 97,628
Percent of gross premiums written	[2]	5.80%	7.60%	4.20%	4.30%
Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 122,811	$ 129,424	$ 517,814	$ 509,602
Percent of gross premiums written		33.00%	32.30%	22.40%	22.60%
Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	$ 37,204	$ 30,726	$ 405,747	$ 304,680
Percent of gross premiums written	[1]	10.00%	7.60%	17.60%	13.60%
Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[3]	$ 74,100	$ 110,865	$ 545,557	$ 552,447
Percent of gross premiums written	[3]	19.90%	27.50%	23.60%	24.60%
Operating Segments | Validus Re
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		$ 94,741	$ 103,297	$ 1,072,219	$ 1,112,410
Operating Segments | Validus Re | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		31,345	34,968	455,826	544,988
Operating Segments | Validus Re | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	4,145	5,477	51,384	52,765
Operating Segments | Validus Re | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		57	473	6,906	11,980
Operating Segments | Validus Re | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		4,536	6,165	30,270	47,182
Operating Segments | Validus Re | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		17,036	17,079	36,610	34,011
Operating Segments | Validus Re | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(33)	(10)	39,892	39,174
Operating Segments | Validus Re | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		149	315	3,646	3,097
Operating Segments | Validus Re | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[2]	2,360	2,643	22,307	24,323
Operating Segments | Validus Re | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		28,250	32,142	191,015	212,532
Operating Segments | Validus Re | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	22,399	9,542	169,737	132,353
Operating Segments | Validus Re | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[3]	12,747	26,645	255,641	222,537
Operating Segments | Talbot Segment
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		189,674	226,025	752,058	789,148
Operating Segments | Talbot Segment | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		19,937	21,886	85,182	89,980
Operating Segments | Talbot Segment | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	40,058	30,721	105,590	95,894
Operating Segments | Talbot Segment | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		3,238	3,520	7,613	6,569
Operating Segments | Talbot Segment | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		4,957	7,839	25,673	31,637
Operating Segments | Talbot Segment | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		25,173	27,249	76,577	78,634
Operating Segments | Talbot Segment | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		997	1,149	5,579	4,746
Operating Segments | Talbot Segment | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		2,015	1,455	5,577	5,452
Operating Segments | Talbot Segment | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[2]	19,166	28,380	76,456	76,368
Operating Segments | Talbot Segment | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		95,604	100,313	303,065	299,300
Operating Segments | Talbot Segment | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	12,771	20,296	75,423	74,794
Operating Segments | Talbot Segment | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[3]	61,362	83,530	288,388	325,074
Operating Segments | Western World
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		85,260	70,871	236,190	207,372
Operating Segments | Western World | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		85,260	70,871	236,190	207,372
Operating Segments | Western World | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	0	0	0	0
Operating Segments | Western World | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	0	0	0
Operating Segments | Western World | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	0	0	0
Operating Segments | Western World | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	0	0	0
Operating Segments | Western World | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	0	0	0
Operating Segments | Western World | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	0	0	0
Operating Segments | Western World | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[2]	0	0	0	0
Operating Segments | Western World | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	0	0	0
Operating Segments | Western World | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	0	0	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	0	0
Operating Segments | AlphaCat
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[4]	4,413	9,891	270,666	174,491
Operating Segments | AlphaCat | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		1,837	4,076	64,566	41,021
Operating Segments | AlphaCat | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	(288)	101	22,219	8,107
Operating Segments | AlphaCat | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	0	4,949	624
Operating Segments | AlphaCat | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	(8)	3,306	2,504
Operating Segments | AlphaCat | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	0	0	0
Operating Segments | AlphaCat | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	0	3,221	1,671
Operating Segments | AlphaCat | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		0	(30)	223	458
Operating Segments | AlphaCat | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[2]	0	0	0	0
Operating Segments | AlphaCat | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(288)	63	33,918	13,364
Operating Segments | AlphaCat | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	2,872	4,960	170,639	115,264
Operating Segments | AlphaCat | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[3]	(8)	792	1,543	4,842
Eliminations
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(1,670)	(7,575)	(21,882)	(35,520)
Eliminations | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(76)	(307)	(1,631)	(2,189)
Eliminations | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	(39)	(208)	(650)	(1,141)
Eliminations | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		6	(85)	(107)	(211)
Eliminations | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		40	(101)	(668)	(1,005)
Eliminations | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(793)	(2,024)	(6,330)	(9,837)
Eliminations | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		7	(84)	(24)	(142)
Eliminations | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(42)	(71)	(129)	(195)
Eliminations | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[2]	66	(521)	(2,276)	(3,063)
Eliminations | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written		(755)	(3,094)	(10,184)	(15,594)
Eliminations | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[1]	(838)	(4,072)	(10,052)	(17,731)
Eliminations | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	[3]	$ (1)	$ (102)	$ (15)	$ (6)

[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.

[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