Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Tax Disclosure [Abstract]
Domestic	$ 46,950,000	$ 49,484,000	$ (29,766,000)
Foreign	50,790,000	49,365,000	6,626,000
Income (loss) from continuing operation before provision (benefit) for taxes on income	97,740,000	98,849,000	(23,140,000)
Domestic [Abstract]
Taxes currently payable, Federal	11,793,000	12,287,000	7,628,000
Taxes currently payable, State and local	2,145,000	1,861,000	68,000
Deferred income taxes	(1,886,000)	411,000	(23,722,000)
Domestic tax provision (benefit)	12,052,000	14,559,000	(16,026,000)
Foreign [Abstract]
Taxes currently payable	12,298,000	13,043,000	10,906,000
Deferred income taxes	3,136,000	1,361,000	(267,000)
Foreign tax provision (benefit)	15,433,000	14,404,000	10,639,000
Total tax provision (benefit)	27,486,000	28,963,000	(5,387,000)
Reconciliation of U. S. federal statutory tax rate to effective tax rate [Abstract]
U.S. statutory tax rate (in hundredths)	35.00%	35.00%	(35.00%)
Depletion (in hundredths)	(4.10%)	(3.80%)	(13.90%)
Difference between tax provided on foreign earnings and the U.S. statutory rate (in hundredths)	(1.00%)	(3.10%)	4.30%
Change in Mexican law (in hundredths)	(0.20%)	0.30%	6.40%
State and local taxes, net of Federal tax benefit (in hundredths)	1.20%	1.20%	(12.10%)
Tax credits and foreign dividends (in hundredths)	(0.10%)	(0.10%)	(1.40%)
Decrease in valuation allowance (in hundredths)	(1.20%)	(0.10%)	27.00%
Impact of uncertain tax positions (in hundredths)	(2.80%)	(1.50%)	0.10%
Other (in hundredths)	1.30%	1.40%	1.30%
Consolidated effective tax rate (in hundredths)	28.10%	29.30%	(23.30%)
Deferred tax assets [Abstract]
Accrued expenses	9,752,000	13,890,000
Net operating loss carry forwards	11,083,000	10,725,000
Pension and post-retirement benefits costs	40,584,000	19,857,000
Other	11,163,000	10,990,000
Valuation allowance	(6,860,000)	(6,276,000)
Total deferred tax assets	65,722,000	49,186,000
Deferred tax liabilities [Abstract]
Plant and equipment, principally due to differences in depreciation	(4,832,000)	(6,203,000)
Intangible assets	(11,387,000)	(10,527,000)
Mexican tax recapture	(1,021,000)	(1,549,000)
Other	(4,067,000)	(2,000,000)
Total deferred tax liabilities	(21,307,000)	(20,279,000)
Net deferred tax (assets) liabilities	44,415,000	28,907,000
Net deferred tax assets, current	4,903,000	8,378,000
Net deferred assets, long term	39,512,000	20,529,000
Operating Loss Carryforwards [Line Items]
Deferred tax assets arising from tax loss carry forwards which will be realized through future operations	6,700,000
Unrecognized tax benefits [Abstract]
Unrecognized tax benefits that would impact effective tax rate	2,300,000
Unrecognized tax benefits [Roll forward]
Balance as of beginning of year	6,473,000	8,496,000
Increases related to current year positions	563,000	329,000
Increases (decreases) related to new judgments	(373,000)	0
Decreases related to audit settlements and statute expirations	(2,751,000)	(2,234,000)
Other	0	(118,000)
Balance as of end of year	3,912,000	6,473,000	8,496,000
Unrecognized tax benefits, net reversal of accrued interest and penalties	1,100,000
Unrecognized tax benefits, accrued interest and penalties	700,000
Cash paid for income taxes [Abstract]
Net cash paid for income taxes	31,900,000	24,900,000	14,100,000
Undistributed earnings of foreign subsidiaries [Abstract]
Foreign subsidiaries' undistributed earnings for which the company has not provided for withholding taxes	317,200,000
Estimated incremental taxes that may be incurred on foreign subsidiaries' undistributed earnings were the earnings to be repatriated	39,200,000
Indefinite lived tax loss carry forwards [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax assets arising from tax loss carry forwards which will be realized through future operations	4,900,000
Finite lived tax loss carry forwards [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax assets arising from tax loss carry forwards which will be realized through future operations	$ 1,800,000
Expiration period (in years)	20