Basis Of Presentation And Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable	$ 4,269,808	$ 4,309,484
Mezzanine notes payable	309,148	309,796
Unsecured senior notes	5,288,503	5,287,704
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable	4,401,756	4,449,541
Mezzanine notes payable	306,130	306,156
Unsecured senior notes	5,602,523	5,645,819
Total	10,310,409	10,401,516
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable	4,269,808	4,309,484
Mezzanine notes payable	309,148	309,796
Unsecured senior notes	5,288,503	5,287,704
Total	$ 9,867,459	$ 9,906,984