BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Investments (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investments in Real Estate
Impairment of real estate	$ 0	$ 0	$ 2,800	$ 66,200	$ 69,000	$ 0	$ 13,100
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