Cash, Cash Equivalents, and Cash Restricted for Regulatory Purposes for Periods Presented in Consolidated Statement of Financial Condition - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 1,907,926	$ 2,199,985
Cash segregated for regulatory purposes	21,372	29,017
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations, Total	$ 1,929,298	$ 2,229,002	$ 1,607,838	$ 2,149,657