RENTALS UNDER OPERATING LEASES - Concentration Risk (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Property | Major Customers | Percent of property related income
Lessor, Lease, Description [Line Items]
Concentration risk percentage	48.70%	37.30%	38.10%
Property | The Glenn, Centennial, CO | Major Customers | Percent of property related income
Lessor, Lease, Description [Line Items]
Concentration risk percentage	17.80%	0.00%	0.00%
Property | Providence Square, Marietta, GA, Retail | Major Customers | Percent of property related income
Lessor, Lease, Description [Line Items]
Concentration risk percentage	11.10%	13.50%	13.70%
Property | Seattle East Industrial, Redmond, WA | Major Customers | Percent of property related income
Lessor, Lease, Description [Line Items]
Concentration risk percentage	10.50%	12.90%	13.60%
Property | The Flats at Carrs Hill, Athens, GA | Major Customers | Percent of property related income
Lessor, Lease, Description [Line Items]
Concentration risk percentage	9.30%	10.90%	10.80%
Tenant | FedEx Ground - Seattle East Industrial | Percent of property related income
Lessor, Lease, Description [Line Items]
Concentration risk percentage	10.50%	12.90%	13.60%
Tenant | FedEx Ground - Seattle East Industrial | Percent of in-place annualized base rental revenues as of
Lessor, Lease, Description [Line Items]
Concentration risk percentage	11.10%	11.80%	14.80%
Tenant | Northrop Grumman Systems Corporation - Loudoun Gateway | Percent of in-place annualized base rental revenues as of
Lessor, Lease, Description [Line Items]
Concentration risk percentage	9.10%	9.30%	11.40%
Tenant | Major Customers | Percent of property related income
Lessor, Lease, Description [Line Items]
Concentration risk percentage	10.50%	12.90%	13.60%
Tenant | Major Customers | Percent of in-place annualized base rental revenues as of
Lessor, Lease, Description [Line Items]
Concentration risk percentage	20.20%	21.10%	26.20%