SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Estimated Useful Lives of Assets by Class (Details) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2021
Property, Plant and Equipment [Abstract]
Remaining non-cancelable term of leases for amortization			5 years
Impairment charges of real estate assets	$ 0	$ 0
Buildings [Member] | Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives of assets			16 years
Buildings [Member] | Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives of assets			45 years
Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives of assets			5 years
Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives of assets			15 years
Land Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives of assets			5 years
Land Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives of assets			15 years
Furniture, Fixtures and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives of assets			3 years
Furniture, Fixtures and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives of assets			7 years
In-Place Leases [Member] | Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives of assets			1 year
In-Place Leases [Member] | Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives of assets			10 years