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	Dec. 31, 2025	Dec. 31, 2024
Receivables from broker-dealers, clearing organizations and customers:
Securities failed-to-deliver - broker-dealers and clearing organizations	$ 244,405	$ 109,307
Securities failed-to-deliver - customers	131,632	136,424
Cash deposits with clearing organizations and broker-dealers	107,223	107,652
Other	5,951	4,345
Total	489,211	357,728
Payables to broker-dealers, clearing organizations and customers:
Securities failed-to-receive - broker-dealers and clearing organizations	224,844	158,694
Securities failed-to-receive - customers	93,107	51,916
Other	8,008	8,235
Total	$ 325,959	$ 218,845