Cash, Cash Equivalents, and Cash Restricted for Regulatory Purposes for Periods Presented in Consolidated Statement of Financial Condition - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 1,577,677	$ 1,963,326
Cash segregated for regulatory purposes	30,161	186,331
Total cash, cash equivalents, and cash segregated for regulatory purposes	$ 1,607,838	$ 2,149,657