Summary of Significant Accounting Policies (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2012 Customer	Dec. 31, 2011 Customer	Dec. 31, 2010 Customer	Dec. 31, 2009
Summary of Significant Accounting Policies (Textual) [Abstract]
Cash and cash equivalents	$ 76,875,000	$ 84,099,000	$ 111,198,000	$ 98,518,000
Reclassification of cumulative translation adjustments (gains) to AOCI	197,000
Summary of Significant Accounting Policies (Additional Textual) [Abstract]
Ownership percentage	80.00%
No single customer comprised more than 10 percent of the Company's consolidated net sales	0	0	0
Percentage of LIFO Inventory	59.00%	66.00%
Cost of maintenance and repairs	45,072,000	43,128,000	36,912,000
Percentage of machinery and equipment representing manufacturing equipment		90.00%
Capitalized Environmental expenditures depreciation period	10 years
Total research and development expenses	28,032,000	25,128,000	24,218,000
Common stock split ratio, description	two-for-one
Accumulated Other Comprehensive Income (Loss) [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Reclassification of cumulative translation adjustments (gains) to AOCI	197,000
Natural Gas [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Volume in derivative contract	1,100,000
Purchased Contract Price	4,224,000
Electricity [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Energy units in Derivative Contract	14,000
Purchased Contract Price	956,000
Building [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Lives used for calculating depreciation expense	30 years
Building Improvements [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Lives used for calculating depreciation expense	15 years
Maximum [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Amortization periods for the identifiable intangible assets	15 years
Maximum [Member] | Machinery and Equipment [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Lives used for calculating depreciation expense	15 years
Maximum [Member] | Furniture and Fixtures [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Lives used for calculating depreciation expense	10 years
Maximum [Member] | Vehicles [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Lives used for calculating depreciation expense	5 years
Maximum [Member] | Computer Equipment and Software [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Lives used for calculating depreciation expense	10 years
Minimum [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Amortization periods for the identifiable intangible assets	5 years
Minimum [Member] | Machinery and Equipment [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Lives used for calculating depreciation expense	10 years
Minimum [Member] | Furniture and Fixtures [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Lives used for calculating depreciation expense	5 years
Minimum [Member] | Vehicles [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Lives used for calculating depreciation expense	3 years
Minimum [Member] | Computer Equipment and Software [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Lives used for calculating depreciation expense	3 years
Money Market Funds [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Cash and cash equivalents	25,600,000
Demand Deposits [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Cash and cash equivalents	7,300,000
Non-US Subsidiaries [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Cash and cash equivalents	$ 44,000,000