Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net	$ 78,800	$ 80,000
Note receivable, net	15,794	15,920
Mortgage notes payable, net	2,919,157	2,922,408
Unsecured senior notes, net	8,393,009	8,390,459
Unsecured line of credit	250,000	0
Unsecured term loan, net	499,058	498,939
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net	78,800	80,000
Note receivable, net	15,794	15,920
Assets, Fair Value Disclosure	94,594	95,920
Mortgage notes payable, net	2,919,157	2,922,408
Unsecured senior notes, net	8,393,009	8,390,459
Unsecured line of credit	250,000	0
Unsecured term loan, net	499,058	498,939
Total	12,061,224	11,811,806
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net	83,707	81,931
Note receivable, net	15,593	14,978
Assets, Fair Value Disclosure	99,300	96,909
Mortgage notes payable, net	3,054,533	2,984,956
Unsecured senior notes, net	8,449,511	8,826,375
Unsecured line of credit	249,873	0
Unsecured term loan, net	500,506	500,561
Total	$ 12,254,423	$ 12,311,892