ACCUMULATED OTHER COMPREHENSIVE INCOME, Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Changes in accumulated other comprehensive income (loss) [Abstract]
Net foreign currency translation adjustment	$ 5,404	$ (1,390)	$ (2,615)
Net change in postretirement benefit plan (see Note 10 for further information) [Abstract]
Initial adoption of new plan	0	(444)	0
Net gain/(loss) arising during the period	(49)	101	242
Amortization of prior service credit/(cost)	74	57	(18)
Amortization of (gain)/loss	(15)	(10)	0
Total before tax	10	(296)	224
Tax	(207)	(49)	(72)
Net of tax	(197)	(345)	152
Other comprehensive income/(loss)	$ 5,207	$ (1,735)	$ (2,463)