Receivables from and Payables to Broker-dealers, Clearing Organizations and Customers - Schedule of Receivables from and Payables to Broker-dealers, Clearing Organizations and Customers (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Receivables from broker-dealers, clearing organizations and customers:
Securities failed-to-deliver - broker-dealers and clearing organizations	$ 231,955	$ 109,307
Securities failed-to-deliver - customers	181,769	136,424
Cash deposits with clearing organizations and broker-dealers	139,515	107,652
Other	5,881	4,345
Total	559,120	357,728
Payables to broker-dealers, clearing organizations and customers:
Securities failed-to-receive - broker-dealers and clearing organizations	242,148	158,694
Securities failed-to-receive - customers	80,003	51,916
Other	7,634	8,235
Total	$ 329,785	$ 218,845