REVENUE RECOGNITION AND ACCOUNTS RECEIVABLE - Summary of Accounts Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 50,593	$ 60,521
Medicaid
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	19,218	21,998
Medicare
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	9,962	11,811
Managed Care
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	6,615	9,103
Private Pay and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 14,798	$ 17,609