VARIABLE INTEREST ENTITIES (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Non-consolidated Variable Interest Entities | VIEs in the form of direct equity interests and a convertible note
VARIABLE INTEREST ENTITIES
Carrying Amount of Assets	$ 4,438	$ 10,640
Maximum exposure to loss	4,438	10,640
Non-consolidated Variable Interest Entities | VIEs in the form of trading margin accounts
VARIABLE INTEREST ENTITIES
Carrying Amount of Assets	9,784
Maximum exposure to loss	10,703
Consolidated Variable Interest Entities
VARIABLE INTEREST ENTITIES
Total assets of consolidated VIE	6,428	5,618
Total liabilities of consolidated VIE	$ 1,558	$ 1,154