EMPLOYEE BENEFIT PLANS (Recognized in Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Amounts recognized in the consolidated balance sheets
Current liabilities (included in current portion of pension and postretirement liabilities)	$ (8,659)	$ (753)
Noncurrent liabilities (included in pension and postretirement liabilities)	(31,504)	(39,827)
Nonunion Defined Benefit Pension Plan
Amounts recognized in the consolidated balance sheets
Current liabilities (included in current portion of pension and postretirement liabilities)	(6,727)
Noncurrent liabilities (included in pension and postretirement liabilities)		(12,586)
Liabilities recognized	(6,727)	(12,586)
Supplemental Benefit Plan
Amounts recognized in the consolidated balance sheets
Current liabilities (included in current portion of pension and postretirement liabilities)	(937)
Noncurrent liabilities (included in pension and postretirement liabilities)	(3,011)	(3,897)
Liabilities recognized	(3,948)	(3,897)
Postretirement Health Benefit Plan
Amounts recognized in the consolidated balance sheets
Current liabilities (included in current portion of pension and postretirement liabilities)	(995)	(753)
Noncurrent liabilities (included in pension and postretirement liabilities)	(28,493)	(23,344)
Liabilities recognized	$ (29,488)	$ (24,097)