Investments - Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Cost	$ 73,749	$ 31,999
Fair Value	80,335	39,990
Sponsored funds
Debt Securities, Available-for-sale [Line Items]
Cost	63,090	22,378
Fair Value	66,326	25,909
Equity investments
Debt Securities, Available-for-sale [Line Items]
Cost	10,659	9,614
Fair Value	14,009	14,078
Debt securities
Debt Securities, Available-for-sale [Line Items]
Cost	0	7
Fair Value	$ 0	$ 3