STOCKHOLDERS' EQUITY AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Summary (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	$ 257,696	$ 318,420
Comprehensive income (loss)	5,463	(65,601)
Stock repurchased	(201)	(8)
Stock issued under employee plans	642	31
Stock-based compensation expense	950	735
Balance at end of period	264,550	253,577
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	257,696	318,420
Net gain (loss) on foreign currency translation	(3,014)	(9,957)
Balance at end of period	264,550	253,577
AOCI Attributable to Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at end of period	(17,973)	(35,159)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at end of period	(17,973)	(35,159)
Foreign currency translation
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	(3,514)	(18,022)
Balance at end of period	(6,528)	(27,979)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	(3,514)	(18,022)
Net gain (loss) on foreign currency translation	(4,048)	(9,957)
Amounts reclassified from accumulated other comprehensive income	1,034	0
Other comprehensive income (loss), net of tax	(3,014)	(9,957)
Balance at end of period	(6,528)	(27,979)
Tax benefit of reclassification of accumulated loss on foreign currency translation	(200)
Pension and other postretirement benefit plans
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	(5,608)	(3,080)
Balance at end of period	(5,243)	(2,749)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	(5,608)	(3,080)
Amounts reclassified from accumulated other comprehensive income	365	331
Other comprehensive income (loss), net of tax	365	331
Balance at end of period	(5,243)	(2,749)
Loss reclassified from AOCI for defined benefit pension plans	400	400
Tax benefit reclassified from AOCI for defined benefit pension plans	100	100
Unrealized gain/(loss) on derivative instruments
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	(9,220)	(4,877)
Balance at end of period	(6,202)	(4,431)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	(9,220)	(4,877)
Net loss on derivative instruments	2,400	446
Amounts reclassified from accumulated other comprehensive income	618	0
Other comprehensive income (loss), net of tax	3,018	446
Balance at end of period	(6,202)	(4,431)
Taxes on unrealized losses on the fair value of hedging activities	700	$ 100
Impact of de-designation of interest rate swap agreement	$ 200