ACQUISITIONS AND DISPOSITIONS - Carrying Value of Assets and Liabilities at Time of Sale and Held for Sale (Details) - USD ($) $ in Thousands			1 Months Ended	3 Months Ended
	Mar. 14, 2019	Mar. 01, 2019	Jul. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Disposal Group
Ownership sold, percentage					100.00%
Liabilities
Deferred loan costs					$ 1,417
Debt, accumulated amortization					(494)
Payment of mortgages payable				$ 0	46,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations
Assets
Investments in real estate, net					270,910
Deferred rent receivable and charges, net					32,284
Other intangible assets, net					316
Total assets					303,510
Liabilities
Debt, net					278,777
Total liabilities					$ 278,777
Office Property, San Fransisco California | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Liabilities
Outstanding amount	$ 28,200
Office Property, Washington, D.C. | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Liabilities
Payment of mortgages payable		$ 46,000
Two Office Properties and One Developmental Site, Washington, D.C. | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Disposal Group
Ownership sold, percentage			100.00%
Mortgage loan with a fixed interest of 4.14% per annum, due on July 1, 2026 | Properties Used As Collateral For Loans | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Liabilities
Defeased amount		$ 205,500