Debt (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Debt Instrument [Line Items]
Debt	$ 8,551,000		$ 5,743,000
Current portion of long-term debt	(6,551,000)		(3,314,000)
Long-term debt	2,000,000		2,429,000
Letter of credit - original face amount	3,332,493
Percent of subsidiary stock not security for financing	65.00%
Interest expense for settlements related to swaps	21,000	31,000
Deferred Tax Assets, Net of Valuation Allowance	1,911,000		1,911,000
Capex Loan [Member]
Debt Instrument [Line Items]
Debt	3,714,000		4,143,000
Long-term Debt, Maturities, Repayment Term	7 years
Mexican Loan [Member]
Debt Instrument [Line Items]
Debt	0		1,600,000
Long-term Debt, Maturities, Repayment Term	5 years
Line of Credit [Member]
Debt Instrument [Line Items]
Debt	4,837,000		0
Revolving Line of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	18,000,000
Capex Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	12,000,000
Debt Instrument, Interest Rate, Stated Percentage	1.75%		1.77%
Mexican Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	8,000,000
Debt Instrument, Interest Rate, Stated Percentage			1.73%
Line of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	8,000,000
Debt Instrument, Description of Variable Rate Basis	daily LIBOR
Debt Instrument, Interest Rate, Stated Percentage	1.73%
Debt Instrument, Basis Spread on Variable Rate	1.60%
Industrial Development Revenue Bond Swap Agreement [Member]
Debt Instrument [Line Items]
Derivative, Fixed Interest Rate	4.89%
Derivative, Description of Variable Rate Basis	76% of the 30-day commercial paper rate
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.
Capex Loan Swap Agreement [Member]
Debt Instrument [Line Items]
Derivative, Fixed Interest Rate	2.295%
Derivative, Description of Variable Rate Basis	LIBOR
Derivative, Variable Interest Rate	0.15%
Description of Reclassification of Cash Flow Hedge Gain (Loss)	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.
Interest rate swaps	85,000		103,000
Interest income (loss) for mark-to-market adjustment of swap fair value	18,000
Derivative, Notional Amount	$ 3,714,000		$ 4,143,000