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Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net	$ 77,592	$ 80,000
Notes receivable, net	25,304	15,920
Mortgage notes payable, net	2,912,494	2,922,408
Unsecured senior notes, net	9,636,397	8,390,459
Unsecured line of credit	0	0
Unsecured term loan, net	499,270	498,939
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net	77,592	80,000
Notes receivable, net	25,304	15,920
Total	102,896	95,920
Mortgage notes payable, net	2,912,494	2,922,408
Unsecured senior notes, net	9,636,397	8,390,459
Unsecured line of credit	0	0
Unsecured term loan, net	499,270	498,939
Total	13,048,161	11,811,806
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net	84,990	81,931
Notes receivable, net	25,974	14,978
Total	110,964	96,909
Mortgage notes payable, net	3,183,294	2,984,956
Unsecured senior notes, net	10,491,966	8,826,375
Unsecured line of credit	0	0
Unsecured term loan, net	500,388	500,561
Total	$ 14,175,648	$ 12,311,892

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Summary Of Significant Accounting Policies [Line Items]

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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