Notes Payable, Bank Credit Facility, Interest and Amortization of Deferred Debt Costs - Scheduled Maturities of Debt, Including Scheduled Principal Amortization (Details) - USD ($)	Sep. 30, 2023	Dec. 31, 2022
Principal Payments
October 1 through December 31, 2023	$ 8,424,000
2024	83,981,000
2025	303,085,000
2026	162,468,000
2027	123,792,000
2028	41,863,000
Thereafter	636,763,000
Principal amount	1,360,376,000	$ 1,240,000,000
Unamortized deferred debt costs	17,064,000	15,800,000
Net	1,343,312,000
Outstanding line of credit	249,521,000	$ 161,941,000
Line of Credit
Principal Payments
Line of credit facility, maximum borrowing capacity	525,000,000
Unsecured Revolving Credit Facility
Principal Payments
Outstanding line of credit	351,000,000
Unsecured Revolving Credit Facility | Line of Credit
Principal Payments
Outstanding line of credit	251,000,000
Term Facility | Line of Credit
Principal Payments
Line of credit facility, maximum borrowing capacity	$ 100,000,000