CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Changes in AOCI by component
Beginning balance, net of tax	$ (46,023)	$ (46,485)	$ (54,656)	$ (48,713)
Other comprehensive (loss) income before reclassifications	342	1,307	7,124	2,036
Total before tax	(540)	(1,434)	(2,372)	(3,038)
Net other comprehensive (loss) income	882	2,741	9,496	5,074
Income tax (benefit) expense	(178)	322	(197)	427
Ending balance, net of tax	(44,963)	(44,066)	(44,963)	(44,066)
Foreign currency translation adjustments
Changes in AOCI by component
Beginning balance, net of tax	24,228	21,359	15,483	20,529
Other comprehensive (loss) income before reclassifications	266	(368)	9,199	531
Total before tax	0	0	0	0
Net other comprehensive (loss) income	266	(368)	9,199	531
Income tax (benefit) expense	(259)	256	(71)	325
Ending balance, net of tax	24,753	20,735	24,753	20,735
Retirement plans related adjustments
Changes in AOCI by component
Beginning balance, net of tax	(70,188)	(67,815)	(70,102)	(69,100)
Other comprehensive (loss) income before reclassifications	160	1,471	(1,812)	1,185
Total before tax	(898)	(1,560)	(2,619)	(3,148)
Net other comprehensive (loss) income	1,058	3,031	807	4,333
Income tax (benefit) expense	147	53	(18)	70
Ending balance, net of tax	(69,277)	(64,837)	(69,277)	(64,837)
Unrealized gain (loss) on cash flow hedges
Changes in AOCI by component
Beginning balance, net of tax	(63)	(29)	(37)	(142)
Other comprehensive (loss) income before reclassifications	(84)	204	(263)	320
Total before tax	358	126	247	110
Net other comprehensive (loss) income	(442)	78	(510)	210
Income tax (benefit) expense	(66)	13	(108)	32
Ending balance, net of tax	$ (439)	$ 36	$ (439)	$ 36