Basis Of Presentation And Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	$ 2,982,067	$ 2,063,087
Mezzanine notes payable	0	307,093
Unsecured line of credit	0	0
Unsecured senior notes, net	7,252,567	7,245,953
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	2,982,067	2,063,087
Mezzanine notes payable	0	307,093
Unsecured senior notes, net	7,252,567	7,245,953
Total	10,234,634	9,616,133
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	3,049,617	2,092,237
Mezzanine notes payable	0	308,344
Unsecured senior notes, net	7,533,164	7,428,077
Total	$ 10,582,781	$ 9,828,658