Leases (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012 years
Operating Leased Assets [Line Items]
Weighted Average Remaining Term Of Tenant Leases	9 years
Operating Leases, Future Minimum Payments Receivable	$ 18,640,077
Maximum Current Term	20
Tenant Leases Remaining in Current Year [Member]
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Receivable	455,837
Tenant Leases 2013 [Member]
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Receivable	1,836,870
Tenant Leases 2014 [Member]
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Receivable	1,727,539
Tenant Leases 2015 [Member]
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Receivable	1,733,702
Tenant Leases 2016 [Member]
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Receivable	1,686,631
Tenant Leases Thereafter [Member]
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Receivable	$ 11,199,498