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, 2021	Dec. 31, 2020
Receivables from broker-dealers, clearing organizations and customers:
Securities failed-to-deliver - broker-dealers	$ 152,766	$ 93,294
Securities failed-to-deliver - customers	182,052	87,685
Deposits with clearing organizations and broker-dealers	68,565	97,043
Other	4,963	1,893
Total	408,346	279,915
Payables to broker-dealers, clearing organizations and customers:
Securities failed-to-receive - broker-dealers	166,010	70,917
Securities failed-to-receive - customers	59,879	60,784
Other	3,436	1,625
Total	$ 229,325	$ 133,326