Debt and Leases - Debt (Details) (USD $)			12 Months Ended		12 Months Ended							12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Capex loan	Dec. 31, 2012 Capex loan	Dec. 31, 2013 Mexican loan	Dec. 31, 2012 Mexican loan	Dec. 31, 2013 Industrial Development Revenue Bond	Dec. 31, 2012 Industrial Development Revenue Bond	May 31, 1998 Industrial Development Revenue Bond	Dec. 31, 2013 Revolving line of credit	Dec. 31, 2012 Revolving line of credit	Dec. 31, 2013 Loans payable Capex loan	Dec. 31, 2012 Loans payable Capex loan	Dec. 31, 2013 Loans payable Mexican loan	Dec. 31, 2012 Loans payable Mexican loan	Dec. 31, 2009 Loans payable Mexican loan	Dec. 31, 2013 Loans payable Revolving line of credit	Dec. 31, 2012 Loans payable Revolving line of credit	Dec. 31, 2013 Loans payable Mexican Expansion Revolving Loan	Dec. 31, 2013 Line of credit	Dec. 31, 2013 Line of credit Capex loan	Dec. 31, 2013 Line of credit Mexican loan	Dec. 31, 2013 Line of credit Revolving line of credit	Dec. 31, 2012 Line of credit Revolving line of credit	Dec. 31, 2012 Line of credit Letter of credit
Debt:
Debt	$ 5,743,000	$ 9,477,000	$ 4,143,000	$ 5,857,000	$ 1,600,000	$ 3,200,000	$ 0	$ 420,000		$ 0	$ 0
Current portion of long-term debt	(3,314,000)	(3,734,000)
Long-term debt	2,429,000	5,743,000
Stated interest rate			1.77%	1.96%	1.73%	1.94%		0.30%
Repayment term			7 years		5 years
Debt instrument, face amount			12,000,000		8,000,000				7,500,000			12,000,000									12,000,000	8,000,000			3,332,493
Percent of subsidiary stock not security for financing	65.00%																			65.00%
Line of credit facility, maximum borrowing capacity																				18,000,000			18,000,000	8,000,000
Description of variable rate basis												30 day LIBOR		daily LIBOR		daily LIBOR				daily LIBOR
Basis spread on variable rate												1.60%	1.75%	1.60%	1.75%		1.60%	1.75%	1.60%
Interest rate at period end												0.17%		0.13%
Annual maturities of long-term debt:
2014	3,314,000
2015	1,714,000
2016	$ 715,000