ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Changes in accumulated other comprehensive income (loss) [Abstract]
Net foreign currency translation adjustment	$ 2,346		$ (215)		$ 3,127	$ (1,304)
Unrealized gain (loss) on cash flow hedge	49		(1,706)		(3,884)	(1,706)
Tax	172		407		998	407
Net of tax	221		(1,299)		(2,886)	(1,299)
Net change in postretirement benefit plan (see Note 15 for further information)
Amortization of prior service cost	19		18		38	36
Amortization of gain	(13)		(11)		(26)	(22)
Total before tax	6		7		12	14
Tax	2		(1)		1	(3)
Adjustment	0		0		(584)	0
Net of tax and adjustment	8		6		(571)	11
Other comprehensive gain (loss)	2,575	$ (2,905)	(1,508)	$ (1,084)	(330)	(2,592)
Gain (loss) related to net investment hedge	(1,514)		$ (2,911)		2,905	$ (2,911)
Tax expense (benefit) on net investment hedge	$ 260				$ (914)