Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable	$ 80,000	$ 0
Mortgage notes payable, net	2,964,572	2,979,281
Unsecured senior notes, net	7,544,697	7,247,330
Unsecured line of credit	0	45,000
Unsecured term loan, net	498,488	0
Total	2,995,328
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable	80,000	0
Note receivable	19,468	0
Total	99,468	0
Mortgage notes payable, net	2,964,572	2,979,281
Unsecured senior notes, net	7,544,697	7,247,330
Unsecured line of credit	0	45,000
Unsecured term loan, net	498,488	0
Total	11,007,757	10,271,611
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable	80,000	0
Note receivable	19,468	0
Total	99,468	0
Mortgage notes payable, net	2,903,925	3,042,920
Unsecured senior notes, net	7,469,338	7,461,615
Unsecured line of credit	0	45,000
Unsecured term loan, net	500,783	0
Total	$ 10,874,046	$ 10,549,535