SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Patient Accounts Receivable Narrative (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Percentage of patient receivables outstanding	10.00%
Historical collection rate from Medicare	99.00%
Portion of accounts receivable derived from Medicare	68.00%	64.00%
Rate of request for anticipated payment submitted for the initial period of care		20.00%