VARIABLE INTEREST ENTITY - Summary of GEM's operations (Unaudited) (Details) (GEM, USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012
GEM
Variable Interest Entity [Line Items]
Revenues		$ 5,340
Net income		$ 4,362

The amount of income between the reporting entity and the Variable Interest Entity (VIE).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 6

-Subparagraph d

-URI http://asc.fasb.org/extlink&oid=28200181&loc=d3e5747-111685

Name:	us-gaap_VariableInterestEntityActivityBetweenVIEAndEntityRevenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration