Debt - Aggregate Principal Repayments on Mortgage Notes (Details) - Mortgages [Member] - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
October 1, 2021 - December 31, 2021	$ 399
2022	239,201
2023	124,217
2024	621,021
2025	1,078
2026	1,138
Thereafter	4,749
Total	$ 991,803	$ 1,333,195

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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