Accumulated Other Comprehensive Earnings (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period			$ 769,042
Balance at the end of the period	$ 769,276	$ 752,819	769,276	$ 752,819
Foreign Currency Translation Adjustment
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(24,313)	(24,978)	(24,882)	(24,581)
Other comprehensive earnings (loss) before reclassifications	(106)	590	463	193
Other comprehensive earnings (loss) net of tax	(106)	590	463	193
Balance at the end of the period	(24,419)	(24,388)	(24,419)	(24,388)
Investments
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(5,722)	1,116	(1,286)	1,992
Other comprehensive earnings (loss) before reclassifications	(1,849)	(283)	(6,281)	(1,159)
Reclassifications from accumulated other comprehensive loss	(4)	(40)	(8)	(40)
Other comprehensive earnings (loss) net of tax	(1,853)	(323)	(6,289)	(1,199)
Balance at the end of the period	(7,575)	793	(7,575)	793
Foreign Currency Derivatives
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	302	572	322	589
Other comprehensive earnings (loss) before reclassifications	(113)	70	(56)	131
Reclassifications from accumulated other comprehensive loss	(65)	(99)	(142)	(177)
Other comprehensive earnings (loss) net of tax	(178)	(29)	(198)	(46)
Balance at the end of the period	124	543	124	543
Commodity Derivatives
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	184	508	94	713
Other comprehensive earnings (loss) before reclassifications	(61)	568	50	869
Reclassifications from accumulated other comprehensive loss	(47)	(504)	(68)	(1,010)
Other comprehensive earnings (loss) net of tax	(108)	64	(18)	(141)
Balance at the end of the period	76	572	76	572
Postretirement and Pension Benefits
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	582	1,205	739	1,472
Reclassifications from accumulated other comprehensive loss	(156)	(266)	(313)	(533)
Other comprehensive earnings (loss) net of tax	(156)	(266)	(313)	(533)
Balance at the end of the period	426	939	426	939
Accumulated Other Comprehensive Earnings (Loss).
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(28,967)	(21,577)	(25,013)	(19,815)
Other comprehensive earnings (loss) before reclassifications	(2,129)	945	(5,824)	34
Reclassifications from accumulated other comprehensive loss	(272)	(909)	(531)	(1,760)
Other comprehensive earnings (loss) net of tax	(2,401)	36	(6,355)	(1,726)
Balance at the end of the period	$ (31,368)	$ (21,541)	$ (31,368)	$ (21,541)