INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Mid-Atlantic Office JV (Details) $ in Millions		3 Months Ended
Dec. 21, 2020 USD ($) ft² property	Dec. 31, 2021 USD ($) property
Schedule of Equity Method Investments [Line Items]
Number of real estate properties \| property		81
Mid-Atlantic Office JV Loan
Schedule of Equity Method Investments [Line Items]
Proceeds from issuance of secured debt		$ 2.2
Secured construction loan with total borrowing capacity		$ 24.4
Mid-Atlantic Office Venture
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 Venture \| Mid-Atlantic Office JV Loan \| Maximum
Schedule of Equity Method Investments [Line Items]
Debt instrument, interest rate, stated percentage	5.60%
Mid-Atlantic Office Venture \| LIBOR \| Mid-Atlantic Office JV Loan
Schedule of Equity Method Investments [Line Items]
Variable interest rate	3.15%
Mid-Atlantic Office Venture \| Preferred Equity Securities
Schedule of Equity Method Investments [Line Items]
Ownership percentage	25.00%
Investment in real estate venture	$ 20.0
Mid-Atlantic Office Venture \| Common Equity Securities
Schedule of Equity Method Investments [Line Items]
Ownership percentage	15.00%
Mid-Atlantic Office Venture \| Office Properties
Schedule of Equity Method Investments [Line Items]
Number of real estate properties \| property	12
Rentable square feet \| ft²	1,128,645
Aggregate sales price	$ 192.9
Mid-Atlantic Office Venture \| Office Properties \| Philadelphia CBD
Schedule of Equity Method Investments [Line Items]
Number of real estate properties \| property	9
Mid-Atlantic Office Venture \| Office Properties \| Metropolitan Washington, D.C.
Schedule of Equity Method Investments [Line Items]
Number of real estate properties \| property	3

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