Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	$ 2,063,087	$ 3,435,242
Mezzanine notes payable	307,093	308,482
Unsecured senior notes, net	7,245,953	5,264,819
Total	2,031,615
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	2,063,087	3,435,242
Mezzanine notes payable	307,093	308,482
Unsecured senior notes, net	7,245,953	5,264,819
Total	9,616,133	9,008,543
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	2,092,237	3,503,746
Mezzanine notes payable	308,344	306,103
Unsecured senior notes, net	7,428,077	5,547,738
Total	$ 9,828,658	$ 9,357,587