ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Components of 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
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 869,642	$ 849,492	$ 828,233	$ 792,523	$ 766,271	$ 743,667	$ 828,233	$ 743,667
Other comprehensive (loss) income	(3,010)	1,883	(5,624)	4,677	2,575	(2,905)	(6,751)	4,347
Ending balance	889,078	869,642	849,492	819,443	792,523	766,271	889,078	819,443
Foreign currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			7,653				7,653
Other comprehensive (loss) income							(7,981)
Ending balance	(328)						(328)
Cash flow hedge
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(3,684)				(3,684)
Other comprehensive (loss) income							1,204
Ending balance	(2,480)						(2,480)
Postretirement benefit plan
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			204				204
Other comprehensive (loss) income							26
Ending balance	230						230
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	432	(1,451)	4,173	(5,894)	(8,469)	(5,564)	4,173	(5,564)
Other comprehensive (loss) income	(3,010)	1,883	(5,624)	4,677	2,575	(2,905)
Ending balance	$ (2,578)	$ 432	$ (1,451)	$ (1,217)	$ (5,894)	$ (8,469)	$ (2,578)	$ (1,217)