Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Revenues	$ 224,384	$ 213,536	$ 446,426	$ 411,410
Investment management fees
Disaggregation of Revenue [Line Items]
Revenues	191,652	179,979	380,012	344,457
Open-end funds
Disaggregation of Revenue [Line Items]
Revenues	79,883	78,161	158,563	149,427
Closed-end funds
Disaggregation of Revenue [Line Items]
Revenues	14,405	14,674	28,799	29,352
Retail separate accounts
Disaggregation of Revenue [Line Items]
Revenues	52,216	42,803	101,197	82,882
Institutional accounts
Disaggregation of Revenue [Line Items]
Revenues	$ 45,148	$ 44,341	$ 91,453	$ 82,796