Investments - Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Cost	$ 97,147	$ 80,912
Fair Value	97,304	76,999
Sponsored funds
Debt Securities, Available-for-sale [Line Items]
Cost	80,794	67,472
Fair Value	77,433	62,744
Equity investments
Debt Securities, Available-for-sale [Line Items]
Cost	16,353	13,440
Fair Value	$ 19,871	$ 14,255