SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Patient Accounts Receivable Narrative (Details) - day	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Concentration Risk [Line Items]
Accounts receivable derived from Medicare	63.00%	58.00%
Percentage of patient receivables outstanding	10.00%
Historical collection rate from Medicare	99.00%
Rate of request for anticipated payment submitted for the initial episode of care	20.00%
Maximum days to submit final bill from the start of episode	90
Maximum days to submit final bill from the date the request for anticipated payment was paid	60