Basis Of Presentation And Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	$ 3,416,622	$ 3,435,242
Mezzanine notes payable	308,142	308,482
Unsecured senior notes, net	6,255,602	5,264,819
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	3,477,310	3,503,746
Mezzanine notes payable	306,089	306,103
Unsecured senior notes, net	6,705,353	5,547,738
Total	10,488,752	9,357,587
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	3,416,622	3,435,242
Mezzanine notes payable	308,142	308,482
Unsecured senior notes, net	6,255,602	5,264,819
Total	$ 9,980,366	$ 9,008,543