Receivable from and payable to brokers, dealers and clearing organizations (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Receivable from brokers, dealers and clearing organizations consisting of:
Securities borrowed	$ 147,647	$ 158,612
Receivable from brokers	57,579	65,639
Clearing organizations and other	35,074	30,789
Securities failed to deliver	20,171	29,656
Total	260,471	284,696
Payable to brokers, dealers and clearing organizations consisting of:
Securities loaned	298,002	284,987
Securities failed to receive	25,573	23,809
Payable to brokers	779	447
Clearing organizations and other	173,012	52,647
Total	$ 497,366	$ 361,890