Investments - Other Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule of Investments [Line Items]
Carrying value	$ 51,752	$ 30,439
% of Total	58.60%	45.40%
Other investments	$ 88,238	$ 67,010
% of Total	100.00%	100.00%
Private equity investments
Schedule of Investments [Line Items]
Carrying value	$ 27,544	$ 23,294
% of Total	31.20%	34.80%
Private credit lending investments
Schedule of Investments [Line Items]
Carrying value	$ 8,451	$ 1,301
% of Total	9.60%	1.90%
Investment in limited partnerships
Schedule of Investments [Line Items]
Carrying value	$ 13,957	$ 3,044
% of Total	15.80%	4.50%
Other investments
Schedule of Investments [Line Items]
Carrying value	$ 1,800	$ 2,800
% of Total	2.00%	4.20%
Investments in direct lending entities
Schedule of Investments [Line Items]
Other investments	$ 36,486	$ 36,571
% of Total	41.40%	54.60%