EMPLOYEE BENEFIT PLAN (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) Plan	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of defined benefit plans | Plan	2
Defined Benefit Plan, Type [Extensible List]	us-gaap:DefinedBenefitPostretirementHealthCoverageMember
Defined Benefit Plan, Funding Status [Extensible List]	us-gaap:UnfundedPlanMember
Amount recognized in consolidated balance sheet for benefit obligations (included in other long-term obligations)	$ 1,603		$ 1,573
Components of net periodic benefit cost [Abstract]
Service cost	19	$ 17
Interest cost	11	12
Amortization of prior service cost	18	19
Amortization of gain	(1)	(4)
Net periodic benefit cost	47	$ 44
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Historical cash payments for retirement medical plan claims per year	$ 100