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Notes Payable, Bank Credit Facility, Interest and Amortization of Deferred Debt Costs - Narrative (Details) | 3 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Mar. 31, 2024 USD ($) | Oct. 01, 2030 | Oct. 01, 2027 | Dec. 31, 2023 USD ($) | Jun. 30, 2023 USD ($) | Aug. 23, 2022 USD ($) swap
Debt Instrument [Line Items] |  |  |  |  |  |
Revolving credit facility payable, net | $ 272,909,000 |  |  | $ 274,715,000 |  |
Number of interest rate swaps | swap |  |  |  |  |  | 2
Construction loans payable, net | 108,917,000 |  |  | 77,305,000 |  |
Long-term debt | 1,408,650,000 |  |  |  |  |
Principal amount | 1,427,291,000 |  |  | 1,410,000,000 |  |
Debt outstanding with fixed-rate | 1,150,000,000 |  |  | 1,130,000,000 |  |
Debt outstanding with variable-rate | 274,000,000 |  |  | 276,000,000 |  |
Carrying value of properties collateralizing mortgage notes | 1,560,000,000 |  |  | 1,520,000,000 |  |
Unamortized deferred debt costs | 18,641,000 |  |  | 19,300,000 |  |
Debt issuance costs amortization | 11,300,000 |  |  | 10,600,000 |  |
Interest rate swaps |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Derivative asset | 4,500,000 |  |  |  |  |
Avenel Business Park |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Guarantor obligations, maximum exposure | $ 6,300,000 |  |  |  |  |
Twinbrook Quarter |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Guarantor Obligations, Liquidation Proceeds, Percentage | 100.00% |  |  |  |  |
Twinbrook Quarter |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Long-term debt |  |  |  | 92,800,000 |  |
Hampden House |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Guarantor obligations, maximum exposure |  |  |  | 21,400,000 |  |
Guarantor Obligations, Liquidation Proceeds, Percentage | 100.00% |  |  |  |  |
Guarantor Obligations, Current Carrying Value | $ 26,600,000 |  |  |  |  |
Secured Overnight Financing Rate (SOFR) |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Interest rate spread on LIBOR | 0.10% |  |  |  |  |
Revolving Credit Facility | Secured Overnight Financing Rate (SOFR) |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Interest rate spread on LIBOR | 1.40% |  |  |  |  |
Term Facility | Secured Overnight Financing Rate (SOFR) |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Interest rate spread on LIBOR | 1.35% |  |  |  |  |
Unsecured Revolving Credit Facility |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Line of credit facility, remaining borrowing capacity | $ 127,600,000 |  |  |  |  |
Revolving credit facility payable, net | 374,000,000 |  |  |  |  |
Line of Credit |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity | 525,000,000 |  |  |  |  |
Line of Credit | Revolving Credit Facility |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity | 425,000,000 |  |  |  |  |
Line of Credit | Term Facility |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity | $ 100,000,000 |  |  |  |  |
Line of credit facility, extension term | 1 year |  |  |  |  |
Line of Credit | Unsecured Revolving Credit Facility |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Revolving credit facility payable, net | $ 274,000,000 |  |  |  |  |
Secured Debt | Term Loan |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity |  |  |  |  |  | $ 100,000,000
Secured Debt | Term Loan | Agreement Ending October 1, 2030 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Derivative, notional amount |  |  |  |  |  | 50,000,000
Secured Debt | Term Loan | Agreement Ending October 1, 2027 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Derivative, notional amount |  |  |  |  |  | $ 50,000,000
Secured Debt | Construction-to-Permanent Loan |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Debt instrument, face amount | 18,600,000 |  |  | 133,000,000 |  |
Secured Debt | Secured Overnight Financing Rate (SOFR) | Term Loan | Agreement Ending October 1, 2030 | Forecast |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Derivative, fixed interest rate (as a percent) |  | 2.91% |  |  |  |
Secured Debt | Secured Overnight Financing Rate (SOFR) | Term Loan | Agreement Ending October 1, 2027 | Forecast |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Derivative, fixed interest rate (as a percent) |  |  | 2.96% |  |  |
Construction Loans | Construction-to-Permanent Loan |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity |  |  |  |  | $ 145,000,000 |
Construction loans payable, net | 90,300,000 |  |  |  |  |
Mortgages | Avenel Business Park |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Long-term debt | 21,300,000 |  |  |  |  |
Mortgages | The Waycroft Mortgage |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Guarantor obligations, maximum exposure | 23,600,000 |  |  |  |  |
Long-term debt | $ 148,100,000 |  |  |  |  |
Mortgages | Ashbrook Marketplace Mortgage |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Long-term debt |  |  |  | 20,100,000 |  |
Mortgages | Kentlands Place Mortgage |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Long-term debt |  |  |  | $ 27,100,000 |  |

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