REVENUE AND ACCOUNTS RECEIVABLE - ACCOUNTS RECEIVABLE (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accounts Receivable [Abstract]
Accounts receivable, gross	$ 36,203	$ 32,860
Less: allowance for doubtful accounts	(655)	(677)
Accounts receivable, net	35,548	32,183
Medicare
Accounts Receivable [Abstract]
Accounts receivable, gross	21,252	17,822
Medicaid
Accounts Receivable [Abstract]
Accounts receivable, gross	6,841	6,579
Managed care
Accounts Receivable [Abstract]
Accounts receivable, gross	4,266	4,380
Private and other
Accounts Receivable [Abstract]
Accounts receivable, gross	$ 3,844	$ 4,079