ACCRUED LIABILITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Liabilities Disclosure [Abstract]
Accrued insurance	$ 2,762	$ 2,900
Accrued payroll and related expenses	10,110	4,729
Other	3,735	5,990
Total	$ 16,607	$ 13,619