BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Investments in Real Estate (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Investments in Real Estate
Impairment of real estate	$ 0	$ 0	$ 0	$ 0
Buildings and improvements | Minimum
Investments in Real Estate
Estimated useful lives			15 years
Buildings and improvements | Maximum
Investments in Real Estate
Estimated useful lives			40 years
Furniture, fixtures, and equipment | Minimum
Investments in Real Estate
Estimated useful lives			3 years
Furniture, fixtures, and equipment | Maximum
Investments in Real Estate
Estimated useful lives			5 years