Subsequent Events (Details) (Common Stock Class A, USD $)	6 Months Ended	1 Months Ended
Jun. 30, 2012	Aug. 31, 2012 Subsequent Event [Member] Repurchase of Equity [Member]
Subsequent Event [Line Items]
Stock Repurchase Program, Authorized Amount	$ 20,000,000	$ 15,000,000

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

No definition available.

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