Investments - Other Investments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Schedule of Investments [Line Items]
Carrying value	$ 66,537		$ 66,537		$ 54,687
% of Total	57.40%		57.40%		56.00%
Other investments	$ 116,016		$ 116,016		$ 97,663
% of Total	100.00%		100.00%		100.00%
Impairment	$ 0	$ 0	$ 0	$ 0
Private equity funds
Schedule of Investments [Line Items]
Carrying value	$ 30,849		$ 30,849		$ 23,324
% of Total	26.60%		26.60%		23.90%
Private credit funds
Schedule of Investments [Line Items]
Carrying value	$ 24,092		$ 24,092		$ 20,863
% of Total	20.80%		20.80%		21.30%
Other privately held investments
Schedule of Investments [Line Items]
Carrying value	$ 11,596		$ 11,596		$ 10,500
% of Total	10.00%		10.00%		10.80%
Investments in direct lending entities (at cost)
Schedule of Investments [Line Items]
Other investments	$ 49,479		$ 49,479		$ 42,976
% of Total	42.60%		42.60%		44.00%