ACCUMULATED OTHER COMPREHENSIVE INCOME - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net foreign currency translation adjustment	$ (2,982)	$ 5,404	$ (1,390)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax [Abstract]
Initial adoption of new plan	0	0	(444)
Net gain/(loss) arising during the period	522	(49)	101
Amortization of prior service credit/(cost)	74	74	57
Amortization of (gain)/loss	(8)	(15)	(10)
Total before tax	588	10	(296)
Tax	434	(207)	(49)
Net of tax	1,022	(197)	(345)
Other comprehensive (loss)/income	$ (1,960)	$ 5,207	$ (1,735)