STOCKHOLDERS' EQUITY (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Changes in accumulated other comprehensive income (loss), net of tax
Beginning Balance	$ (32,682)	$ 5,137	$ (26,778)
Before-Tax Amount	3,147	(54,177)	54,929
Tax Benefit (Expense)	(7,783)	16,358	(23,014)
Total other comprehensive income (loss), net of tax	(4,636)	(37,819)	31,915
Ending Balance	(37,318)	(32,682)	5,137
Pension and other postretirement liability adjustment
Changes in accumulated other comprehensive income (loss), net of tax
Beginning Balance	(34,777)	(9,229)	(45,958)
Before-Tax Amount	19,728	(41,906)	59,743
Tax Benefit (Expense)	(7,783)	16,358	(23,014)
Total other comprehensive income (loss), net of tax	11,945	(25,548)	36,729
Ending Balance	(22,832)	(34,777)	(9,229)
Foreign currency translation adjustment
Changes in accumulated other comprehensive income (loss), net of tax
Beginning Balance	2,095	14,366	19,180
Before-Tax Amount	(16,581)	(12,271)	(4,814)
Tax Benefit (Expense)	0	0	0
Total other comprehensive income (loss), net of tax	(16,581)	(12,271)	(4,814)
Ending Balance	$ (14,486)	$ 2,095	$ 14,366