Accumulated Other Comprehensive Earnings (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	$ 698,183
Balance at the end of the period	697,164	$ 687,831
AOCI from Derivatives | Foreign currency forward contracts
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(1,675)	(1,236)
Other comprehensive earnings (loss) before reclassifications	427	(1,214)
Reclassifications from accumulated other comprehensive loss	387	327
Other comprehensive earnings (loss) net of tax	814	(887)
Balance at the end of the period	(861)	(2,123)
AOCI from Derivatives | Commodity futures contracts
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	173	(470)
Other comprehensive earnings (loss) before reclassifications	187	(722)
Reclassifications from accumulated other comprehensive loss	4	103
Other comprehensive earnings (loss) net of tax	191	(619)
Balance at the end of the period	364	(1,089)
Investments
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(605)	(332)
Other comprehensive earnings (loss) before reclassifications	312	237
Reclassifications from accumulated other comprehensive loss	3
Other comprehensive earnings (loss) net of tax	315	237
Balance at the end of the period	(290)	(95)
Postretirement and Pension Benefits
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	6,387	6,439
Reclassifications from accumulated other comprehensive loss	(262)	(232)
Other comprehensive earnings (loss) net of tax	(262)	(232)
Balance at the end of the period	6,125	6,207
Foreign Currency Translation
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(21,644)	(17,499)
Other comprehensive earnings (loss) before reclassifications	205	(1,159)
Other comprehensive earnings (loss) net of tax	205	(1,159)
Balance at the end of the period	(21,439)	(18,658)
Accumulated Other Comprehensive Earnings ( Loss )
Accumulated other comprehensive earnings (loss), net of tax
Balance at the beginning of the period	(17,364)	(13,098)
Other comprehensive earnings (loss) before reclassifications	1,131	(2,858)
Reclassifications from accumulated other comprehensive loss	132	198
Other comprehensive earnings (loss) net of tax	1,263	(2,660)
Balance at the end of the period	$ (16,101)	$ (15,758)