REAL ESTATE SALES - Revenue and Expenses (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020 USD ($) numberOfProperties	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) numberOfProperties	Sep. 30, 2019 USD ($)
Disposed of by Sale
Revenues:
Rental income	$ 0	$ 572	$ 100	$ 1,682
Other operating income	0	17	0	59
Total revenues	0	589	100	1,741
Expenses
Operating, maintenance, and management	0	171	41	493
Property management fees and expenses to affiliate	0	8	1	25
Real estate taxes and insurance	0	77	15	226
Asset management fees to affiliate	0	55	10	163
General and administrative expenses	0	4	18	9
Depreciation and amortization	0	130	0	414
Interest expense	0	203	30	839
Total expenses	$ 0	$ 648	$ 115	$ 2,169
Held-for-Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties \| numberOfProperties	0		0
Office Building
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold \| numberOfProperties			1
Number of real estate properties \| numberOfProperties	3		3

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