Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 906,949	$ 845,268	$ 886,379
Investment management fees
Disaggregation of Revenue [Line Items]
Revenues	773,830	711,475	728,339
Open-end funds
Disaggregation of Revenue [Line Items]
Revenues	317,990	305,238	335,585
Closed-end funds
Disaggregation of Revenue [Line Items]
Revenues	59,184	58,136	63,841
Retail separate accounts
Disaggregation of Revenue [Line Items]
Revenues	209,467	171,357	171,509
Institutional accounts
Disaggregation of Revenue [Line Items]
Revenues	$ 187,189	$ 176,744	$ 157,404