OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Pension and postretirement benefits [Abstract]
Amortization of net actuarial loss, Gross Amount	[1]	$ 231	$ 580	$ 694	$ 1,739
Amortization of net actuarial loss, Income Tax (Provision) Benefit	[1]	(59)	(142)	(177)	(423)
Amortization of net actuarial loss, Net Amount	[1]	172	438	517	1,316
Actuarial gains (losses), Gross Amount	[1]			8,167	(609)
Actuarial gains (losses), Income Tax (Provision) Benefit	[1]			(2,044)	148
Actuarial gains (losses), Net Amount	[1]			6,123	(461)
Reclassification to retained earnings of stranded tax effects from tax reform, Gross Amount				0	0
Reclassification to retained earnings of stranded tax effects from tax reform, Income Tax (Provision) Benefit				0	(7,925)
Reclassification to retained earnings of stranded tax effects from tax reform, Net Amount				0	(7,925)
Foreign currency translation, Gross Amount		(618)	(60)	(542)	(69)
Foreign currency translation, Income Tax (Provision) Benefit		0	0	0	0
Foreign currency translation, Net Amount		(618)	(60)	(542)	(69)
Total other comprehensive income, Gross Amount		(387)	520	8,319	1,061
Total other comprehensive income, Income Tax (Provision) Benefit		(59)	(142)	(2,221)	(8,200)
Total other comprehensive income (loss), net of taxes		$ (446)	$ 378	$ 6,098	$ (7,139)

[1] Actuarial gains/(losses) are amortized into other income (expense). (See Note 13 - Retirement Plans)