Investments - Other Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Schedule of Investments [Line Items]
Carrying value	$ 37,684	$ 30,439
% of Total	50.80%	45.40%
Other investments	$ 74,217	$ 67,010
% of Total	100.00%	100.00%
Private equity investments
Schedule of Investments [Line Items]
Carrying value	$ 27,544	$ 23,294
% of Total	37.10%	34.80%
Private credit lending investments
Schedule of Investments [Line Items]
Carrying value	$ 5,109	$ 1,301
% of Total	6.90%	1.90%
Investment in limited partnerships
Schedule of Investments [Line Items]
Carrying value	$ 3,231	$ 3,044
% of Total	4.40%	4.50%
Other investments
Schedule of Investments [Line Items]
Carrying value	$ 1,800	$ 2,800
% of Total	2.40%	4.20%
Investments in direct lending entities
Schedule of Investments [Line Items]
Other investments	$ 36,533	$ 36,571
% of Total	49.20%	54.60%