ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accrued compensation and benefits:
Accrued compensation	$ 17,913	$ 24,526
Accrued vacation pay	14,937	12,670
Accrued compensation and benefits	32,850	37,196
Accrued expenses and other current liabilities:
Refunds due to payors	25,132	20,085
Other	16,043	10,935
Accrued settlement	6,573	6,573
Accrued expenses and other current liabilities	$ 47,748	$ 37,593