Organization (Details)	Dec. 31, 2011
Organization (Textual) [Abstract]
Percentage of stake acquired in Gresham	60.00%

In a business combination achieved in stages, this element represents the acquisition-date percentage of equity in the acquiree held by the acquirer immediately before the acquisition date.

No definition available.

Name:	us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant