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	Jun. 30, 2015	Dec. 31, 2014
Receivable from brokers, dealers and clearing organizations consist of:
Securities borrowed	$ 279,695	$ 242,172
Receivable from brokers	19,867	38,149
Securities failed to deliver	16,723	11,055
Clearing organizations	23,265	21,106
Other	17,620	1,993
Receivables from brokers, dealers and clearing organizations	357,170	314,475
Payable to brokers, dealers and clearing organizations consist of:
Securities loaned	209,226	137,892
Payable to brokers	6,454	4,559
Securities failed to receive	20,491	23,573
Other	1,836	91,137
Payable to brokers, dealers and clearing organizations	$ 238,007	$ 257,161