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 AOCI by component
Beginning balance, net of tax	$ (50,310)	$ (44,905)	$ (54,656)	$ (48,713)
Other comprehensive (loss) income before reclassifications	3,011	(2,161)	6,782	728
Total before tax	(838)	(863)	(1,832)	(1,605)
Net other comprehensive (loss) income	3,849	(1,298)	8,614	2,333
Income taxes	438	(282)	19	(105)
Ending balance, net of tax	(46,023)	(46,485)	(46,023)	(46,485)
Foreign currency translation adjustments
Changes in AOCI by component
Beginning balance, net of tax	19,324	24,312	15,483	20,529
Other comprehensive (loss) income before reclassifications	4,675	(2,840)	8,933	899
Total before tax	0	0	0	0
Net other comprehensive (loss) income	4,675	(2,840)	8,933	899
Income taxes	229	(113)	(188)	(69)
Ending balance, net of tax	24,228	21,359	24,228	21,359
Retirement plans related adjustments
Changes in AOCI by component
Beginning balance, net of tax	(69,816)	(69,221)	(70,102)	(69,100)
Other comprehensive (loss) income before reclassifications	(1,403)	775	(1,972)	(287)
Total before tax	(876)	(800)	(1,721)	(1,589)
Net other comprehensive (loss) income	(527)	1,575	(251)	1,302
Income taxes	155	(169)	165	(17)
Ending balance, net of tax	(70,188)	(67,815)	(70,188)	(67,815)
Unrealized gain (loss) on cash flow hedges
Changes in AOCI by component
Beginning balance, net of tax	182	4	(37)	(142)
Other comprehensive (loss) income before reclassifications	(261)	(96)	(179)	116
Total before tax	38	(63)	(111)	(16)
Net other comprehensive (loss) income	(299)	(33)	(68)	132
Income taxes	54	0	42	(19)
Ending balance, net of tax	$ (63)	$ (29)	$ (63)	$ (29)