INVESTMENTS IN REAL ESTATE - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($) ft²	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) ft²	Sep. 30, 2020 USD ($) property
Asset Acquisition [Line Items]
Depreciation expense	$ 4,300	$ 4,400	$ 12,700	$ 13,000
Acquisition of real estate			$ 2,933	$ 0
Number of property acquisitions (in properties) | property				0
Number of property disposed (in properties) | property				0
Office Property In Los Angeles, California
Asset Acquisition [Line Items]
Percentage of ownership acquired	100.00%		100.00%
Acquisition of real estate			$ 2,900
Transaction costs in acquisition of real estate			$ 33
Property area (in sq feet) | ft²	4,455		4,455