REVENUE AND ACCOUNTS RECEIVABLE - ACCOUNTS RECEIVABLE (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable [Abstract]
Accounts receivable, gross	$ 32,860	$ 25,085
Less: allowance for doubtful accounts	(677)	(616)
Accounts receivable, net	32,183	24,469
Medicare
Accounts Receivable [Abstract]
Accounts receivable, gross	17,822	11,457
Medicaid
Accounts Receivable [Abstract]
Accounts receivable, gross	6,579	6,692
Managed care
Accounts Receivable [Abstract]
Accounts receivable, gross	4,380	3,079
Private and other
Accounts Receivable [Abstract]
Accounts receivable, gross	$ 4,079	$ 3,857