ACCUMULATED OTHER COMPREHENSIVE LOSS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	$ 733,840
Adoption of ASU 2018-02	2,726
Balance at the end of the period	750,622	$ 733,840
Foreign Currency Derivatives
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	51	(76)
Other comprehensive earnings (loss) before reclassifications	(318)	152
Reclassifications from accumulated other comprehensive loss	(51)	(25)
Other comprehensive earnings (loss) net of tax	(369)	127
Balance at the end of the period	(309)	51
Foreign Currency Derivatives | ASU 2018-02
Accumulated other comprehensive earnings (loss), net of tax
Adoption of ASU 2018-02	9
Investments
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(889)	(697)
Other comprehensive earnings (loss) before reclassifications	(459)	(192)
Other comprehensive earnings (loss) net of tax	(459)	(192)
Balance at the end of the period	(1,516)	(889)
Investments | ASU 2018-02
Accumulated other comprehensive earnings (loss), net of tax
Adoption of ASU 2018-02	(168)
Postretirement and Pension Benefits
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	3,289	4,873
Other comprehensive earnings (loss) before reclassifications	1,172	(651)
Reclassifications from accumulated other comprehensive loss	(1,003)	(933)
Other comprehensive earnings (loss) net of tax	169	(1,584)
Balance at the end of the period	4,206	3,289
Postretirement and Pension Benefits | ASU 2018-02
Accumulated other comprehensive earnings (loss), net of tax
Adoption of ASU 2018-02	748
Foreign Currency Translation
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(24,262)	(25,460)
Other comprehensive earnings (loss) before reclassifications	103	1,198
Other comprehensive earnings (loss) net of tax	103	1,198
Balance at the end of the period	(24,159)	(24,262)
Commodity Derivatives
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	20	1,114
Other comprehensive earnings (loss) before reclassifications	(1,754)	(1,050)
Reclassifications from accumulated other comprehensive loss	1,286	(44)
Other comprehensive earnings (loss) net of tax	(468)	(1,094)
Balance at the end of the period	(444)	20
Commodity Derivatives | ASU 2018-02
Accumulated other comprehensive earnings (loss), net of tax
Adoption of ASU 2018-02	4
Accumulated Other Comprehensive Earnings ( Loss )
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(21,791)	(20,246)
Other comprehensive earnings (loss) before reclassifications	(1,256)	(543)
Reclassifications from accumulated other comprehensive loss	232	(1,002)
Other comprehensive earnings (loss) net of tax	(1,024)	(1,545)
Balance at the end of the period	(22,222)	$ (21,791)
Accumulated Other Comprehensive Earnings ( Loss ) | ASU 2018-02
Accumulated other comprehensive earnings (loss), net of tax
Adoption of ASU 2018-02	$ 593