Cash, Cash Equivalents, and Cash Restricted for Regulatory Purposes for Periods Presented in Consolidated Statement of Financial Condition - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 1,915,767	$ 3,361,801
Cash segregated for regulatory purposes	29,519	162,048
Total cash, cash equivalents, and cash segregated for regulatory purposes	$ 1,945,286	$ 3,523,849