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INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Mid-Atlantic Office JV (Details) $ in Millions | Dec. 21, 2020 USD ($) ft² property | Dec. 31, 2020 property
--- | --- | ---
Schedule of Equity Method Investments [Line Items] |  |
Number of Properties | property |  | 82
Mid-Atlantic Office JV |  |
Schedule of Equity Method Investments [Line Items] |  |
Ownership percentage | 40.00% | 40.00%
Ownership percentage of total common equity | 20.00% |
Joint venture, funding from debt | $ | $ 147.4 |
Proceeds from issuance of secured debt | $ | $ 120.8 |
Mid-Atlantic Office JV | Mid-Atlantic Office JV Loan | Maximum |  |
Schedule of Equity Method Investments [Line Items] |  |
Debt instrument, interest rate, stated percentage | 5.60% |
Mid-Atlantic Office JV | LIBOR | Mid-Atlantic Office JV Loan |  |
Schedule of Equity Method Investments [Line Items] |  |
Variable interest rate | 3.15% |
Mid-Atlantic Office JV | Preferred Equity Securities |  |
Schedule of Equity Method Investments [Line Items] |  |
Ownership percentage | 25.00% |
Investment in real estate venture | $ | $ 20.0 |
Mid-Atlantic Office JV | Common Equity Securities |  |
Schedule of Equity Method Investments [Line Items] |  |
Ownership percentage | 15.00% |
Mid-Atlantic Office JV | Office Properties |  |
Schedule of Equity Method Investments [Line Items] |  |
Number of Properties | property | 12 |
Rentable square feet | ft² | 1,128,645 |
Sales price | $ | $ 192.9 |
Mid-Atlantic Office JV | Office Properties | Philadelphia CBD |  |
Schedule of Equity Method Investments [Line Items] |  |
Number of Properties | property | 9 |
Mid-Atlantic Office JV | Office Properties | Metropolitan DC |  |
Schedule of Equity Method Investments [Line Items] |  |
Number of Properties | property | 3 |

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