Accrued Expenses and Other Liabilities (Schedule of Accrued Expenses and Other Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Components of accrued expenses
Accrued compensation and related taxes	$ 97,523	$ 71,039
Accrued investment manager fees	95,858	57,894
Accrued technology	8,951	4,701
Accrued professional services	7,746	9,240
Non-income tax payables	4,907	8,398
Other accrued expenses	9,431	7,276
Total accrued expenses and other liabilities	$ 224,416	$ 158,548