v2.4.0.6
Income Taxes (Details Textual) (USD $)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Income Taxes (Textual) [Abstract]      
Qualified domestic production activity deduction $ 1,522,000 $ 1,511,000 $ 1,198,000
Effective tax rate 5.10% 2.00% 5.30%
Income tax payments 15,000,000 16,900,000 7,800,000
Reserve for uncertain tax positions 0    
Date of enactment of American Taxpayer Relief Act Jan. 02, 2013    
Extended expiry date Dec. 31, 2013    
Research and development tax credit 77,000    
Alternative fuel tax credit $ 127,000    
Research and Development Expense [Member]
     
Tax Credit Carryforward [Line Items]      
Expiry date Dec. 31, 2011