Accumulated Other Comprehensive Income (Loss) - Amount Reclassified by Component (Details 2) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Restructuring										$ 252	$ 129
Cost of products sold (excluding depreciation and amortization)									$ (343,522)	(363,014)	(366,962)
Income before income tax provision									63,386	72,508	67,199
Tax (expense) or benefit									(19,923)	(23,138)	(21,486)
Net income	$ 7,716	$ 12,106	$ 12,580	$ 11,061	$ 12,134	$ 12,224	$ 15,203	$ 9,809	43,463	49,370	45,713
Reclassified from Accumulated Other Comprehensive Income (Loss)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Net income									(1,538)	(360)	(1,058)
Foreign Currency Translation Adjustments
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified net of tax											1,032
Foreign Currency Translation Adjustments | Reclassified from Accumulated Other Comprehensive Income (Loss)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Restructuring											1,032
Income before income tax provision											1,032
Net income											1,032
Defined Benefit Pension Plan Adjustments
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified before tax									(3,646)	(1,196)	(3,796)
Amounts reclassified, tax (expense) or benefit									1,316	435	1,441
Amounts reclassified net of tax									(2,330)	(761)	(2,355)
Prior-service costs
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified before tax									(15)	(74)	(74)
Actuarial losses
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified before tax									(3,631)	(1,122)	(3,722)
Derivatives
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified net of tax									792	401	265
Derivatives | Reclassified from Accumulated Other Comprehensive Income (Loss)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Income before income tax provision									1,136	705	463
Tax (expense) or benefit									(344)	(304)	(198)
Net income									792	401	265
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)									2,077	484	1,018
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)									$ (941)	$ 221	$ (555)