Cash, Cash Equivalents, and Cash Restricted for Regulatory Purposes for Periods Presented in Consolidated Statement of Financial Condition - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 3,361,801	$ 2,199,985	$ 1,963,326
Cash segregated for regulatory purposes	162,048	29,017	186,331
Total cash, cash equivalents, and cash segregated for regulatory purposes	$ 3,523,849	$ 2,229,002	$ 2,149,657	$ 2,452,206