Schedule of Debt Net of Unamortized Debt Premium (Discount) and Debt Issuance Costs (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Long-term Debt	$ 3,652,242	$ 3,923,084
Fixed Rate Mortgage Loans [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Contractual Interest Rate	4.20%
Debt, Weighted Average Effective Interest Rate	4.00%
Long-term Debt	$ 265,835	272,750
Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Contractual Interest Rate	3.80%
Debt, Weighted Average Effective Interest Rate	4.00%
Long-term Debt	$ 3,240,705	3,239,609
Total credit facilities		264,679
Notes Payable to Banks [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 3,652,242	3,658,405
Line of Credit [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Contractual Interest Rate	1.00%
Debt, Weighted Average Effective Interest Rate	1.40%
Term Loan [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Contractual Interest Rate	2.00%
Debt, Weighted Average Effective Interest Rate	2.10%
Term Loan [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Total credit facilities		264,679
London Interbank Offered Rate (LIBOR) [Member] | Variable Rate Mortgage Loans [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Contractual Interest Rate	2.80%
Debt, Weighted Average Effective Interest Rate	2.90%
Long-term Debt	$ 145,702	$ 146,046