Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenues	$ 222,042	$ 197,874
Investment management fees
Disaggregation of Revenue [Line Items]
Revenues	188,360	164,478
Open-end funds
Disaggregation of Revenue [Line Items]
Revenues	78,680	71,266
Closed-end funds
Disaggregation of Revenue [Line Items]
Revenues	14,394	14,678
Retail separate accounts
Disaggregation of Revenue [Line Items]
Revenues	48,981	40,079
Institutional accounts
Disaggregation of Revenue [Line Items]
Revenues	$ 46,305	$ 38,455