SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024 USD ($) subsidiary segment	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Property, Plant and Equipment [Line Items]
Implicit price concession recorded as a reduction to patient and resident service revenue	$ 20,956	$ 11,075
Estimated implicit price concessions	53,147		$ 42,171
Advertising expense	$ 2,030	$ 1,815
Number of subsidiaries exclusively operating assisted living facilities | subsidiary	4
Lease term	10 years
Number of reportable segments | segment	1
Accounts Receivable | Customer Concentration Risk | Medicare
Property, Plant and Equipment [Line Items]
Concentration risk	21.00%		20.00%
Accounts Receivable | Customer Concentration Risk | Medicaid
Property, Plant and Equipment [Line Items]
Concentration risk	36.00%		36.00%
Skilled Nursing Beds | Geographic Concentration Risk | CALIFORNIA
Property, Plant and Equipment [Line Items]
Concentration risk	64.00%
Buildings and improvements
Property, Plant and Equipment [Line Items]
Useful life	30 years
Minimum
Property, Plant and Equipment [Line Items]
Renewal term	3 years
Minimum | Buildings and improvements
Property, Plant and Equipment [Line Items]
Useful life	5 years
Minimum | Leasehold improvements
Property, Plant and Equipment [Line Items]
Useful life	5 years
Minimum | Furniture, fixtures, and other
Property, Plant and Equipment [Line Items]
Useful life	3 years
Maximum
Property, Plant and Equipment [Line Items]
Renewal term	20 years
Maximum | Buildings and improvements
Property, Plant and Equipment [Line Items]
Useful life	40 years
Maximum | Leasehold improvements
Property, Plant and Equipment [Line Items]
Useful life	15 years
Maximum | Furniture, fixtures, and other
Property, Plant and Equipment [Line Items]
Useful life	15 years