CONCENTRATION OF CREDIT RISK - Triple-Net Leased Properties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Real estate properties
Other noncash expense	$ 44,503	$ (52,489)	$ (26,404)
Brookdale Senior Living
Real estate properties
Other noncash expense	$ (42,600)	$ (42,600)	$ (42,600)
Customer Concentration Risk | Revenues | Brookdale Senior Living
Real estate properties
Concentration risk	3.30%	3.60%	3.90%
Customer Concentration Risk | Revenues | Ardent
Real estate properties
Concentration risk	3.00%	3.20%	3.30%
Customer Concentration Risk | Revenues | Kindred
Real estate properties
Concentration risk	2.90%	3.20%	3.80%
Customer Concentration Risk | Contribution as a Percentage of Total NOI: | Brookdale Senior Living
Real estate properties
Concentration risk	7.70%	8.10%	8.60%
Customer Concentration Risk | Contribution as a Percentage of Total NOI: | Ardent
Real estate properties
Concentration risk	6.90%	7.10%	7.40%
Customer Concentration Risk | Contribution as a Percentage of Total NOI: | Kindred
Real estate properties
Concentration risk	6.90%	7.30%	7.80%