Composition of Certain Financial Statement Captions (Accrued Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Items Included in Consolidated Statement of Financial Condition [Abstract]
Accrued employee compensation	$ 42,053	$ 107,933
Accrued employee benefits and other personnel	7,117	13,951
Accrued consulting, outsourcing and professional fees	44,175	36,411
Accrued sub-advisory, distribution and other asset management fees	58,087	58,661
Accrued dividend payable	0	55,452
Accrued income taxes	55,278	0
Other accrued liabilities	43,758	51,974
Total accrued liabilities	$ 250,468	$ 324,382