Notes Payable and Unsecured Credit Facilities Schedule of maturities of long-term debt (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
2021	$ 42,279
2022	17,237
2023	75,420
2024	345,591
2025	293,732
Beyond 5 Years	2,906,817
Unamortized debt premium/(discount) and issuance costs	(30,769)
Total	3,650,307	$ 3,923,084
Unsecured Debt [Member]
Debt Instrument [Line Items]
Total	3,241,800	$ 3,239,609
Scheduled Principal Payments [Member] \| Mortgages [Member]
Debt Instrument [Line Items]
2021	5,675
2022	11,389
2023	9,695
2024	4,849
2025	3,732
Beyond 5 Years	10,583
Unamortized debt premium/(discount) and issuance costs	0
Total	45,923
Mortgage Loan Maturities \| Mortgages [Member]
Debt Instrument [Line Items]
2021	36,604
2022	5,848
2023	65,725
2024	90,742
2025	40,000
Beyond 5 Years	121,234
Unamortized debt premium/(discount) and issuance costs	2,431
Total	362,584
Unsecured Maturities [Member] \| Unsecured Debt [Member]
Debt Instrument [Line Items]
2021	0
2022	0
2023	0
2024	250,000
2025	250,000
Beyond 5 Years	2,775,000
Unamortized debt premium/(discount) and issuance costs	(33,200)
Total	$ 3,241,800

Long term debt maturities repayments of principal thereafter.

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