Debt (Details) (USD $)	0 Months Ended	3 Months Ended		9 Months Ended			9 Months Ended			9 Months Ended			9 Months Ended		9 Months Ended
	Mar. 27, 2014	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2014 Industrial Development Revenue Bond Swap Agreement [Member]	Sep. 30, 2014 Industrial Development Revenue Bond Swap Agreement [Member] Accumulated Other-than-Temporary Impairment [Member]	Dec. 31, 2009 Industrial Development Revenue Bond Swap Agreement [Member] Accumulated Other-than-Temporary Impairment [Member]	Sep. 30, 2014 Industrial Development Revenue Bond Swap Agreement [Member] Commercial Paper Rate, 30 Days [Member]	Sep. 30, 2014 Capex Loan Swap Agreement [Member]	Dec. 31, 2013 Capex Loan Swap Agreement [Member]	Sep. 30, 2014 Capex Loan Swap Agreement [Member] Accumulated Other-than-Temporary Impairment [Member]	Mar. 31, 2009 Capex Loan Swap Agreement [Member] Accumulated Other-than-Temporary Impairment [Member]	Sep. 30, 2014 Revolving Credit Facility [Member]	Mar. 27, 2014 Revolving Credit Facility [Member]	Mar. 26, 2014 Revolving Credit Facility [Member]	Dec. 31, 2013 Revolving Credit Facility [Member]	Sep. 30, 2014 Capex Loan [Member]	Dec. 31, 2013 Capex Loan [Member]	Sep. 30, 2014 Mexican Loan [Member]	Dec. 31, 2013 Mexican Loan [Member]	Mar. 27, 2014 Mexican Expansion Revolving Loan [Member] Revolving Credit Facility [Member]
Debt, Long-term and Short-term, Combined Amount [Abstract]
Debt		$ 9,222,000		$ 9,222,000		$ 5,743,000													$ 2,857,000	$ 4,143,000	$ 0	$ 1,600,000
Revolving Line of Credit		6,365,000		6,365,000		0									6,365,000			0
Less current portion		(8,079,000)		(8,079,000)		(3,314,000)
Long-term debt		1,143,000		1,143,000		2,429,000
Debt Instrument, Interest Rate, Stated Percentage																		1.75%	1.75%	1.77%		1.73%
Debt - face amount																			12,000,000		8,000,000
Maximum borrowing capacity																18,000,000	8,000,000
Letter of credit - original face amount		3,332,000		3,332,000
Percent of subsidiary stock not security for financing		65.00%		65.00%
Capital Improvements Excluded From Fixed Charge	18,000,000
Line of Credit Facility, Remaining Borrowing Capacity																							10,000,000
Debt Instrument, Description of Variable Rate Basis															daily LIBOR
Debt Instrument, Basis Spread on Variable Rate															1.60%
Derivative, Fixed Interest Rate							4.89%				2.295%
Variable Rate Receivable										76.00%
Derivative, Description of Variable Rate Basis										76% of the 30-day commercial paper rate	LIBOR
Pre-Tax Loss									200,000					146,000
Amortization of Pre-Tax Loss to Interest Expense, Before Tax, Monthly								5,000					2,000
Amortization of Pre-Tax Loss to Interest Expense, Net of Tax, Monthly								3,000					1,000
Description of Reclassification of Cash Flow Hedge Gain (Loss)							The pre-tax loss previously recognized in Accumulated Other Comprehensive Income, totaling $200,000 as of December 31, 2009, was amortized as an increase to interest expense of $5,000 per month, or $3,000 net of tax, over the remaining term of the interest rate swap agreement.				The pre-tax loss previously recognized in Accumulated Other Comprehensive Income, totaling $146,000 as of March 31, 2009, is being amortized as an increase to interest expense of approximately $2,000 per month, or $1,000 net of tax, over the remaining term of the interest rate swap agreement.
Derivative, Variable Interest Rate											0.15%
Interest rate swaps		50,000		50,000		103,000
Interest income (loss) for mark-to-market adjustment of swap fair value		17,000	19,000	53,000	81,000
Notional amount											2,857,000	4,143,000
Interest expense for settlements related to swaps		$ (16,000)	$ (25,000)	$ (56,000)	$ (87,000)