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	Mar. 31, 2023	Dec. 31, 2022
Receivables from broker-dealers, clearing organizations and customers:
Securities failed-to-deliver - broker-dealers and clearing organizations	$ 126,082	$ 144,523
Securities failed-to-deliver - customers	306,736	235,056
Deposits with clearing organizations and broker-dealers	118,293	88,923
Other	7,143	7,833
Total	558,254	476,335
Payables to broker-dealers, clearing organizations and customers:
Securities failed-to-receive - broker-dealers and clearing organizations	195,910	224,816
Securities failed-to-receive - customers	107,206	71,828
Other	13,158	7,349
Total	$ 316,274	$ 303,993