Summary of Significant Accounting Policies (Details 1)	12 Months Ended
	Dec. 31, 2011
Property and equipment estimated useful lives
Estimated useful lives of leasehold improvements minimum	Lesser of lease term
Buildings and improvements [Member]
Property and equipment estimated useful lives
Minimum	5
Maximum	40
Leasehold improvements [Member]
Property and equipment estimated useful lives
Maximum	15
Furniture and equipment [Member]
Property and equipment estimated useful lives
Minimum	5
Maximum	7
Software [Member]
Property and equipment estimated useful lives
Estimated useful life of capitalized software	3
Equipment held under capital leases [Member]
Property and equipment estimated useful lives
Minimum	5
Maximum	10