Accumulated Other Comprehensive Income (Loss) (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Cost of products sold (excluding depreciation and amortization)	$ (84,804)	$ (90,106)	$ (256,636)	$ (272,822)
Income before income tax provision	17,610	18,450	53,343	54,325
Tax (expense) or benefit	(5,504)	(6,226)	(17,596)	(17,089)
Net income	12,106	12,224	35,747	37,236
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Net income	(242)	(88)	(682)	(259)
Defined Benefit Pension Plan Adjustments
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified before tax	(704)	(297)	(2,090)	(895)
Amounts reclassified, tax (expense) or benefit	246	105	733	324
Amounts reclassified net of tax	(458)	(192)	(1,357)	(571)
Prior-service costs
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified before tax	(4)	(18)	(11)	(55)
Actuarial losses
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified before tax	(700)	(279)	(2,079)	(840)
Derivatives
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified net of tax			675	312
Derivatives | Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Income before income tax provision	308	181	972	559
Tax (expense) or benefit	(92)	(77)	(297)	(247)
Net income	216	104	675	312
Derivatives | Amount 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)	600	90	1,668	306
Derivatives | Amount 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)	$ (292)	$ 91	$ (696)	$ 253