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, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	$ 2,046,959	$ 2,063,087
Mezzanine notes payable	306,734	307,093
Unsecured line of credit	105,000	0
Unsecured senior notes, net	7,248,152	7,245,953
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	2,046,959	2,063,087
Mezzanine notes payable	306,734	307,093
Unsecured line of credit	105,000	0
Unsecured senior notes, net	7,248,152	7,245,953
Total	9,706,845	9,616,133
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	2,074,954	2,092,237
Mezzanine notes payable	307,600	308,344
Unsecured line of credit	105,099	0
Unsecured senior notes, net	7,460,437	7,428,077
Total	$ 9,948,090	$ 9,828,658