SHARE REPURCHASE (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2013	Dec. 31, 2011
SHARE REPURCHASE [Abstract]
Authorized repurchase of outstanding Class A common stock		$ 15
Remaining available shares under repurchase program value	$ 15

The remaining repurchase amount authorized by an entity's Board of Directors under a stock repurchase plan.

No definition available.

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