Accumulated Other Comprehensive Income (Loss) - Amount Reclassified by Component (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Restructuring											$ 252
Cost of products sold (excluding depreciation and amortization)									$ (346,398)	$ (343,522)	(363,014)
Income before income tax provision									20,073	63,386	72,508
Tax (expense) or benefit									(6,276)	(19,923)	(23,138)
Net income	$ (5,942)	$ 6,385	$ 7,896	$ 5,458	$ 7,716	$ 12,106	$ 12,580	$ 11,061	13,797	43,463	49,370
Reclassified from Accumulated Other Comprehensive Income (Loss)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Net income									(3,057)	(1,538)	(360)
Defined Benefit Pension Plan Adjustments
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified before tax									(4,749)	(3,646)	(1,196)
Amounts reclassified, tax (expense) or benefit									1,769	1,316	435
Amounts reclassified net of tax									(2,980)	(2,330)	(761)
Prior-service costs
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified before tax										(15)	(74)
Actuarial losses
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified before tax									(4,749)	(3,631)	(1,122)
Derivatives
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified net of tax									(77)	792	401
Derivatives | Reclassified from Accumulated Other Comprehensive Income (Loss)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Income before income tax provision									(133)	1,136	705
Tax (expense) or benefit									56	(344)	(304)
Net income									(77)	792	401
Derivatives | Reclassified from Accumulated Other Comprehensive Income (Loss) | Foreign exchange contracts
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Cost of products sold (excluding depreciation and amortization)									206	2,077	484
Derivatives | Reclassified from Accumulated Other Comprehensive Income (Loss) | Natural gas contracts
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Cost of products sold (excluding depreciation and amortization)									$ (339)	$ (941)	$ 221