Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable	$ 80,000	$ 80,000
Note receivable	15,920	19,468
Mortgage notes payable, net	2,922,408	2,964,572
Unsecured senior notes, net	8,390,459	7,544,697
Unsecured line of credit	0	0
Unsecured term loan, net	498,939	498,488
Total	2,949,154
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable	80,000	80,000
Note receivable	15,920	19,468
Total	95,920	99,468
Mortgage notes payable, net	2,922,408	2,964,572
Unsecured senior notes, net	8,390,459	7,544,697
Unsecured line of credit	0	0
Unsecured term loan, net	498,939	498,488
Total	11,811,806	11,007,757
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable	81,931	80,000
Note receivable	14,978	19,468
Total	96,909	99,468
Mortgage notes payable, net	2,984,956	2,903,925
Unsecured senior notes, net	8,826,375	7,469,338
Unsecured line of credit	0	0
Unsecured term loan, net	500,561	500,783
Total	$ 12,311,892	$ 10,874,046