Variable Interest Entities and Noncontrolling Interests - Non-redeemable noncontrolling interests (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Noncontrolling Interest [Line Items]
Non-redeemable noncontrolling interests, beginning of period				$ 762,777
Amounts attributable to noncontrolling interests		$ 165,598	$ 12,301	(68,346)	$ 54,683
Other comprehensive (income) loss attributable to noncontrolling interests		20,111	2,891	(12,947)	7,030
Non-redeemable noncontrolling interests, end of period		679,089	855,347	679,089	855,347
Watford Holdings Ltd
Noncontrolling Interest [Line Items]
Non-redeemable noncontrolling interests, beginning of period		492,785	838,081	762,777	791,560
Additional paid in capital attributable to noncontrolling interests		595	2,074	472	2,074
Repurchases attributable to non-redeemable noncontrolling interests	[1]			(2,867)	0
Amounts attributable to noncontrolling interests		165,598	12,301	(68,346)	54,683
Other comprehensive (income) loss attributable to noncontrolling interests		20,111	2,891	(12,947)	7,030
Non-redeemable noncontrolling interests, end of period		$ 679,089	$ 855,347	$ 679,089	$ 855,347
Noncontrolling shareholders | Common shares | Watford Holdings Ltd
Noncontrolling Interest [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners		87.00%		87.00%

[1] During 2020, Watford’s board of directors authorized the investment in Watford’s common shares through a share repurchase program.