Accumulated Other Comprehensive Income (Loss) - Amount Reclassified by Component (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Cost of products sold (excluding depreciation and amortization)	$ (85,430)	$ (84,804)	$ (251,552)	$ (256,636)
Income before income tax provision	7,997	17,610	28,308	53,343
Tax (expense) or benefit	(1,612)	(5,504)	(8,569)	(17,596)
Net income	6,385	12,106	19,739	35,747
Reclassified from Accumulated Other Comprehensive Income (Loss)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Net income	(972)	(242)	(2,072)	(682)
Defined Benefit Pension Plan Adjustments
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified net of tax			(2,002)	(1,357)
Defined Benefit Pension Plan Adjustments | Reclassified from Accumulated Other Comprehensive Income (Loss)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified before tax	(1,566)	(704)	(3,187)	(2,090)
Amounts reclassified, tax (expense) or benefit	586	246	1,185	733
Amounts reclassified net of tax	(980)	(458)	(2,002)	(1,357)
Prior-service costs | Reclassified from Accumulated Other Comprehensive Income (Loss)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified before tax		(4)		(11)
Actuarial losses | Reclassified from Accumulated Other Comprehensive Income (Loss)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified before tax	(1,566)	(700)	(3,187)	(2,079)
Derivatives
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified net of tax			(70)	675
Derivatives | Reclassified from Accumulated Other Comprehensive Income (Loss)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Income before income tax provision	30	308	(126)	972
Tax (expense) or benefit	(22)	(92)	56	(297)
Net income	8	216	(70)	675
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)	(153)	600	281	1,668
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)	$ 183	$ (292)	$ (407)	$ (696)