ACCUMULATED OTHER COMPREHENSIVE LOSS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	$ 750,622
Adoption of ASU 2018-02		$ 2,726
Balance at the end of the period	759,854	750,622
Foreign Currency Translation
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(24,159)	(24,262)
Other comprehensive earnings (loss) before reclassifications	791	103
Other comprehensive earnings (loss) net of tax	791	103
Balance at the end of the period	(23,368)	(24,159)
Investments
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(1,516)	(889)
Other comprehensive earnings (loss) before reclassifications	2,372	(459)
Reclassifications from accumulated other comprehensive loss	26
Other comprehensive earnings (loss) net of tax	2,398	(459)
Balance at the end of the period	882	(1,516)
Investments | ASU 2018-02
Accumulated other comprehensive earnings (loss), net of tax
Adoption of ASU 2018-02		(168)
Foreign Currency Derivatives
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(309)	51
Other comprehensive earnings (loss) before reclassifications	272	(318)
Reclassifications from accumulated other comprehensive loss	47	(51)
Other comprehensive earnings (loss) net of tax	319	(369)
Balance at the end of the period	10	(309)
Foreign Currency Derivatives | ASU 2018-02
Accumulated other comprehensive earnings (loss), net of tax
Adoption of ASU 2018-02		9
Commodity Derivatives
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(444)	20
Other comprehensive earnings (loss) before reclassifications	70	(1,754)
Reclassifications from accumulated other comprehensive loss	466	1,286
Other comprehensive earnings (loss) net of tax	536	(468)
Balance at the end of the period	92	(444)
Commodity Derivatives | ASU 2018-02
Accumulated other comprehensive earnings (loss), net of tax
Adoption of ASU 2018-02		4
Postretirement and Pension Benefits
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	4,206	3,289
Other comprehensive earnings (loss) before reclassifications	(914)	1,172
Reclassifications from accumulated other comprehensive loss	(1,153)	(1,003)
Other comprehensive earnings (loss) net of tax	(2,067)	169
Balance at the end of the period	2,139	4,206
Postretirement and Pension Benefits | ASU 2018-02
Accumulated other comprehensive earnings (loss), net of tax
Adoption of ASU 2018-02		748
Accumulated Other Comprehensive Earnings ( Loss )
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(22,222)	(21,791)
Other comprehensive earnings (loss) before reclassifications	2,591	(1,256)
Reclassifications from accumulated other comprehensive loss	(614)	232
Other comprehensive earnings (loss) net of tax	1,977	(1,024)
Balance at the end of the period	$ (20,245)	(22,222)
Accumulated Other Comprehensive Earnings ( Loss ) | ASU 2018-02
Accumulated other comprehensive earnings (loss), net of tax
Adoption of ASU 2018-02		$ 593