Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net	$ 77,872	$ 77,552
Notes receivable, net	19,087	18,729
Mortgage notes payable, net	2,901,709	2,909,081
Unsecured senior notes, net	9,634,356	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	77,872	77,552
Notes receivable, net	19,087	18,729
Total	96,959	96,281
Mortgage notes payable, net	2,901,709	2,909,081
Unsecured senior notes, net	9,634,356	9,639,287
Unsecured line of credit	0	0
Unsecured term loan, net	0	499,390
Total	12,536,065	13,047,758
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net	83,779	84,579
Notes receivable, net	19,709	19,372
Total	103,488	103,951
Mortgage notes payable, net	3,053,824	3,144,150
Unsecured senior notes, net	10,385,016	10,620,527
Unsecured line of credit	0	0
Unsecured term loan, net	0	500,326
Total	$ 13,438,840	$ 14,265,003