Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Revenues	$ 210,525	$ 224,384	$ 428,457	$ 446,426
Investment management fees
Disaggregation of Revenue [Line Items]
Revenues	179,476	191,652	365,567	380,012
Open-end funds
Disaggregation of Revenue [Line Items]
Revenues	70,379	79,883	144,416	158,563
Closed-end funds
Disaggregation of Revenue [Line Items]
Revenues	14,881	14,405	29,734	28,799
Retail separate accounts
Disaggregation of Revenue [Line Items]
Revenues	51,818	52,216	106,090	101,197
Institutional accounts
Disaggregation of Revenue [Line Items]
Revenues	$ 42,398	$ 45,148	$ 85,327	$ 91,453