Summary of Significant Accounting Policies Basis of Consolidation Policy Additional Information (Details)	6 Months Ended
	Jun. 30, 2011
Ownership Interest to be Held for Consolidation [Line Items]
Ownership Interest To Use Cost Method	20.00%
Maximum [Member]
Ownership Interest to be Held for Consolidation [Line Items]
Ownership Interest to be Held for Consolidation	50.00%
Minimum [Member]
Ownership Interest to be Held for Consolidation [Line Items]
Ownership Interest To Use Equity Method	50.00%