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	Sep. 30, 2022	Dec. 31, 2021
Receivables from broker-dealers, clearing organizations and customers:
Securities failed-to-deliver - broker-dealers and clearing organizations	$ 203,657	$ 152,766
Securities failed-to-deliver - customers	276,272	182,052
Deposits with clearing organizations and broker-dealers	96,315	68,565
Other	8,410	4,963
Total	584,654	408,346
Payables to broker-dealers, clearing organizations and customers:
Securities failed-to-receive - broker-dealers and clearing organizations	211,235	166,010
Securities failed-to-receive - customers	113,826	59,879
Other	11,824	3,436
Total	$ 336,885	$ 229,325