Notes Payable, Bank Credit Facility, Interest and Amortization of Deferred Debt Costs - Scheduled Maturities of Debt, Including Scheduled Principal Amortization (Details) - USD ($)	Jun. 30, 2023	Dec. 31, 2022
Principal Payments
July 1 through December 31, 2023	$ 16,728,000
2024	83,973,000
2025	271,086,000
2026	162,468,000
2027	123,792,000
2028	41,863,000
Thereafter	611,879,000
Principal amount	1,311,789,000	$ 1,240,000,000
Unamortized deferred debt costs	17,659,000	15,800,000
Net	1,294,130,000
Outstanding line of credit	217,328,000	$ 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	319,000,000
Unsecured Revolving Credit Facility \| Line of Credit
Principal Payments
Outstanding line of credit	219,000,000
Term Facility \| Line of Credit
Principal Payments
Line of credit facility, maximum borrowing capacity	$ 100,000,000

Long-Term Debt, Maturities, Repayments of Principal and Balloon Payments [Abstract]

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Long-term Debt Maturities Repayments Of Principal And Balloon Payments After Year Five

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Long-term Debt Maturities Repayments Of Principal And Balloon Payments In Year Five

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Long-term Debt, Maturities, Repayments of Principal and Balloon Payments in Year Four

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Long-term Debt, Maturities, Repayments of Principal and Balloon Payments in Year One

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Long-term Debt, Maturities, Repayments of Principal and Balloon Payments in Year Three

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Long-term Debt, Maturities, Repayments of Principal and Balloon Payments in Year Two

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Long-Term Debt, Maturities, Repayments of Principal and Balloon Payments, Remainder of Fiscal Year

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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, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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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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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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