REVENUE AND ACCOUNTS RECEIVABLE - ACCOUNTS RECEIVABLE (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accounts Receivable [Abstract]
Accounts receivable, gross	$ 34,374	$ 32,860
Less: allowance for doubtful accounts	(516)	(677)
Accounts receivable, net	33,858	32,183
Medicare
Accounts Receivable [Abstract]
Accounts receivable, gross	18,246	17,822
Medicaid
Accounts Receivable [Abstract]
Accounts receivable, gross	7,624	6,579
Managed care
Accounts Receivable [Abstract]
Accounts receivable, gross	4,808	4,380
Private and other
Accounts Receivable [Abstract]
Accounts receivable, gross	$ 3,696	$ 4,079