Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net	$ 78,144	$ 77,552
Notes receivable, net	19,297	18,729
Mortgage notes payable, net	2,898,699	2,909,081
Unsecured senior notes, net	10,479,651	9,639,287
Unsecured line of credit	0	0
Unsecured term loan, net	0	499,390
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net	78,144	77,552
Notes receivable, net	19,297	18,729
Total	97,441	96,281
Mortgage notes payable, net	2,898,699	2,909,081
Unsecured senior notes, net	10,479,651	9,639,287
Unsecured line of credit	0	0
Unsecured term loan, net	0	499,390
Total	13,378,350	13,047,758
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net	83,354	84,579
Notes receivable, net	19,885	19,372
Total	103,239	103,951
Mortgage notes payable, net	3,032,122	3,144,150
Unsecured senior notes, net	11,157,602	10,620,527
Unsecured line of credit	0	0
Unsecured term loan, net	0	500,326
Total	$ 14,189,724	$ 14,265,003