Receivable from and Payable to Brokers, Dealers and Clearing Organizations - Schedule of Receivable from and Payable to Brokers, Dealers and Clearing Organization (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Receivable from brokers, dealers and clearing organizations consist of:
Securities borrowed	$ 296,362	$ 242,172
Receivable from brokers	53,550	38,149
Securities failed to deliver	16,380	11,055
Clearing organizations	23,766	21,106
Other	8,750	1,993
Receivables from brokers, dealers and clearing organizations	398,808	314,475
Payable to brokers, dealers and clearing organizations consist of:
Securities loaned	209,125	137,892
Payable to brokers	4,380	4,559
Securities failed to receive	31,266	23,573
Other	5,742	91,137
Payable to brokers, dealers and clearing organizations	$ 250,513	$ 257,161