Accumulated Other Comprehensive Loss (Details 2) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Amounts reclassified out of accumulated other comprehensive loss
Cost of products sold (excluding depreciation)	$ 92,415,000	$ 93,826,000
Income before income tax provision	14,093,000	11,912,000
Reclassifications from accumulated OCI derivative loss to earnings	44,000
Restructuring	24,000
Tax (expense) or benefit	(4,279,000)	(4,174,000)
Net income	9,814,000	7,738,000
Amounts reclassified from other comprehensive income (loss)	(498,000)
Income tax expense associated with the Company's pension benefits	20,300,000		20,000,000
Income tax benefit associated with the Company's derivatives included in accumulated other comprehensive loss	(400,000)		(29,000)
Income tax expense (benefit) associated with foreign currency translation	200,000	(100,000)
Income tax expense (benefit) associated with pension benefits	(300,000)	(300,000)
Income tax expense (benefit) associated with derivatives	400,000	100,000
Amount Reclassified from Accumulated Other Comprehensive Loss
Amounts reclassified out of accumulated other comprehensive loss
Amounts reclassified from other comprehensive income (loss)	(498,000)
Gains and losses on cash flow hedges
Amounts reclassified out of accumulated other comprehensive loss
Amounts reclassified from other comprehensive income (loss)	25,000
Gains and losses on cash flow hedges | Amount Reclassified from Accumulated Other Comprehensive Loss
Amounts reclassified out of accumulated other comprehensive loss
Reclassifications from accumulated OCI derivative loss to earnings	44,000
Tax (expense) or benefit	(19,000)
Amounts reclassified from other comprehensive income (loss)	25,000
Gains and losses on cash flow hedges | Amount Reclassified from Accumulated Other Comprehensive Loss | Foreign Exchange Contracts
Amounts reclassified out of accumulated other comprehensive loss
Cost of products sold (excluding depreciation)	(170,000)
Gains and losses on cash flow hedges | Amount Reclassified from Accumulated Other Comprehensive Loss | Natural Gas Contracts
Amounts reclassified out of accumulated other comprehensive loss
Cost of products sold (excluding depreciation)	214,000
Pension Benefit Adjustments
Amounts reclassified out of accumulated other comprehensive loss
Pension benefit adjustment amounts reclassified from other comprehensive income (loss), net of tax	(559,000)
Pension Benefit Adjustments | Amount Reclassified from Accumulated Other Comprehensive Loss
Amounts reclassified out of accumulated other comprehensive loss
Prior-service costs	(19,000)
Actuarial losses	(885,000)
Income before income tax provision	(904,000)
Tax (expense) or benefit	345,000
Pension benefit adjustment amounts reclassified from other comprehensive income (loss), net of tax	(559,000)
Foreign Currency Translation Adjustments
Amounts reclassified out of accumulated other comprehensive loss
Amounts reclassified from other comprehensive income (loss)	(1,032,000)
Foreign Currency Translation Adjustments | Amount Reclassified from Accumulated Other Comprehensive Loss
Amounts reclassified out of accumulated other comprehensive loss
Restructuring	1,032,000
Amounts reclassified from other comprehensive income (loss)	$ (1,032,000)