DUE TO PRIME BROKERS (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended	9 Months Ended
	Jul. 24, 2013	Sep. 30, 2013	Dec. 31, 2012
Other Payables to Broker-Dealers and Clearing Organizations		$ 239,074	$ 326,488
Maximum temporary leverage	30.00%	20.00%
Maximum long-term leverage	15.00%	5.00%
Collateral for LOCs issued [Member]
Other Payables to Broker-Dealers and Clearing Organizations		235,200	252,700
Bank Overdrafts [Member]
Other Payables to Broker-Dealers and Clearing Organizations		$ 3,800	$ 73,700