ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS), Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Changes in accumulated other comprehensive income (loss) [Abstract]
Net foreign currency translation adjustment	$ 2,697	$ (707)	$ 3,238	$ 548
Net change in postretirement benefit plan (see Note 14 for further information) [Abstract]
Initial adoption of new plan	0	(444)	0	(444)
Amortization of prior service cost	19	26	38	24
Amortization of gain	(4)	(2)	(8)	(5)
Total before tax	15	(420)	30	(425)
Tax	(4)	(6)	(9)	(5)
Net of tax	11	(426)	21	(430)
Other comprehensive income (loss)	$ 2,708	$ (1,133)	$ 3,259	$ 118