Segment information (Segment reporting by segment - Corporate and Investments) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Net investment income		$ 48,960	$ 44,458	$ 44,241	$ 40,214	$ 38,153	$ 43,514	$ 39,257	$ 29,461	$ 177,873	$ 150,385	$ 127,824
Net realized gains on investments		5,607	906	2,274	(1,164)	9,220	4,397	2,724	(584)	7,623	15,757	2,298
Change in net unrealized gains (losses) on investments		(21,257)	(5,197)	16,321	13,348	(67,460)	5,459	31,428	47,444	3,215	16,871	(32,395)
Income (loss) from investment affiliates		6,345	1,011	9,466	5,188	2,166	453	(589)	(4,113)	22,010	(2,083)	4,281
Net investment return	[1]									210,721	180,930	102,008
General and administrative expenses		97,522	70,342	96,349	87,924	77,955	82,443	89,688	86,208	352,137	336,294	363,709
Share compensation expenses		10,031	9,443	11,146	9,491	10,442	10,501	10,727	11,237	40,111	42,907	38,341
Finance expenses		15,871	14,523	14,209	13,943	14,630	14,521	14,166	15,203	58,546	58,520	74,742
Dividends on preferred shares		5,828	5,627	2,203	2,203	2,203	2,252	0	0	15,861	4,455	0
Tax expense (benefit)		(412)	(2,632)	(987)	(3,549)	(21,147)	1,830	1,706	(2,118)	(7,580)	(19,729)	6,376
Foreign exchange (losses) gains		(283)	(1,404)	(7,329)	1,569	(901)	(766)	6,286	6,245	(7,447)	10,864	(8,731)
Transaction expenses		0	0	(4,427)	0					(4,427)	0	0
Net (loss) income (attributable) available to Validus common shareholders		$ (8,693)	$ (250,446)	$ 101,095	$ 94,561	$ 7,767	$ 89,844	$ 94,963	$ 166,810	(63,483)	359,384	374,893
Corporate and Investments
Segment Reporting Information [Line Items]
Net investment income	[2]									152,955	141,718	121,166
Net realized gains on investments	[2]									7,437	14,680	1,698
Change in net unrealized gains (losses) on investments	[2]									6,371	14,106	(32,007)
Income (loss) from investment affiliates										22,010	(2,083)	4,281
Net investment return	[1]									188,773	168,421	95,138
General and administrative expenses										48,598	72,249	75,724
Share compensation expenses										16,186	16,003	12,955
Finance expenses	[2]									58,194	57,183	61,071
Dividends on preferred shares										15,861	4,455	0
Tax expense (benefit)	[2]									(7,588)	(19,819)	6,376
Total expenses										131,251	130,071	156,126
Foreign exchange (losses) gains	[2]									(8,544)	10,778	(8,172)
Other income (loss)										303	(766)	(1,002)
Transaction expenses										(4,427)	0	0
Total other items										(12,668)	10,012	(9,174)
Net (loss) income (attributable) available to Validus common shareholders										$ 44,854	$ 48,362	$ (70,162)

[1] Net investment return includes net investment income, net realized and change in net unrealized gains (losses) on investments and income (loss) from investment affiliates.

[2] These items exclude the components which are included in the Asset Management segment income (loss) and amounts which are consolidated from VIEs.