INVESTMENTS IN REAL ESTATE - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) property	Dec. 31, 2020 USD ($) property
Business Acquisition [Line Items]
Depreciation expense | $	$ 16.9	$ 17.7
Number of property dispositions | property	0	0
Kaiser Foundation Health Plan, Inc. | Revenues | Customer Concentration Risk
Business Acquisition [Line Items]
Concentration risk	30.90%
1037 North Sycamore, Los Angeles, CA
Business Acquisition [Line Items]
Percentage of ownership acquired	100.00%
1021 East 7th Street, Austin, TX
Business Acquisition [Line Items]
Percentage of ownership acquired		100.00%