Composition of Certain Financial Statement Captions - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Items Included in Consolidated Statement of Financial Condition [Abstract]
Accrued employee compensation	$ 129,228	$ 107,495
Accrued employee benefits and other personnel	8,557	9,797
Accrued voluntary separation program	2,536	21,058
Accrued consulting, outsourcing and professional fees	32,082	32,285
Accrued sub-advisory, distribution and other asset management fees	53,727	49,405
Accrued dividend payable	63,877	61,104	$ 58,051
Other accrued liabilities	57,506	37,801
Accrued liabilities	$ 347,513	$ 318,945