ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Changes in accumulated other comprehensive income (loss) [Abstract]
Net foreign currency translation adjustment	$ (3,362)			$ 4,313			$ (7,981)	$ 7,440
Unrealized gain (loss) on cash flow hedge	450			299			1,583	(3,585)
Tax	(109)			(72)			(379)	926
Net of tax	341			227			1,204	(2,659)
Net change in postretirement benefit plan (see Note 14 for further information)
Amortization of prior service cost	18			18			55	56
Amortization of gain	(4)			(12)			(16)	(38)
Prior service credit	0			0			(4)	0
Total before tax	14			6			35	18
Tax	(3)			2			(9)	3
Adjustment	0			129			0	(455)
Net of tax and adjustment	11			137			26	(434)
Other comprehensive (loss) income	(3,010)	$ 1,883	$ (5,624)	4,677	$ 2,575	$ (2,905)	(6,751)	4,347
Gain (loss) related to net investment hedge	1,715			(3,891)			3,888	(986)
Tax expense (benefit) on net investment hedge	$ 553			$ (1,244)			$ 1,243	$ (330)