CONCENTRATION OF CREDIT RISK - Triple-Net Leased Properties (Details) - Customer Concentration Risk	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues | Brookdale Senior Living
Concentration Risk
Concentration percentage	3.70%	4.10%
Revenues | Ardent
Concentration Risk
Concentration percentage	3.20%	3.50%
Revenues | Kindred
Concentration Risk
Concentration percentage	3.30%	3.60%
NOI | Brookdale Senior Living
Concentration Risk
Concentration percentage	7.80%	8.80%
NOI | Ardent
Concentration Risk
Concentration percentage	6.80%	7.50%
NOI | Kindred
Concentration Risk
Concentration percentage	7.00%	7.80%