Accumulated Other Comprehensive Earnings (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	$ 759,854
Balance at the end of the period	751,732	$ 744,828
Foreign Currency Translation
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(23,368)	(24,159)
Other comprehensive earnings (loss) before reclassifications	(3,674)	391
Other comprehensive earnings (loss) net of tax	(3,674)	391
Balance at the end of the period	(27,042)	(23,768)
Investments
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	882	(1,516)
Other comprehensive earnings (loss) before reclassifications	(827)	1,112
Other comprehensive earnings (loss) net of tax	(827)	1,112
Balance at the end of the period	55	(404)
Foreign Currency Derivatives
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	10	(309)
Other comprehensive earnings (loss) before reclassifications	(155)	159
Reclassifications from accumulated other comprehensive loss	74
Other comprehensive earnings (loss) net of tax	(81)	159
Balance at the end of the period	(71)	(150)
Commodity Derivatives
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	92	(444)
Other comprehensive earnings (loss) before reclassifications	(574)	258
Reclassifications from accumulated other comprehensive loss	118	72
Other comprehensive earnings (loss) net of tax	(456)	330
Balance at the end of the period	(364)	(114)
Postretirement and Pension Benefits
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	2,139	4,206
Reclassifications from accumulated other comprehensive loss	(256)	(288)
Other comprehensive earnings (loss) net of tax	(256)	(288)
Balance at the end of the period	1,883	3,918
Accumulated Other Comprehensive Earnings ( Loss )
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(20,245)	(22,222)
Other comprehensive earnings (loss) before reclassifications	(5,230)	1,920
Reclassifications from accumulated other comprehensive loss	(64)	(216)
Other comprehensive earnings (loss) net of tax	(5,294)	1,704
Balance at the end of the period	$ (25,539)	$ (20,518)