FINANCING AGREEMENTS (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	May 02, 2012	Dec. 31, 2011
Financing arrangements
Outstanding balance	$ 7,923,487		$ 9,345,044
Total long-term debt	3,319,004		2,123,127
Current maturities of long-term debt	(453,105)		(1,310,210)
Long-term debt - net of current maturities	2,865,899		812,917
Future maturity requirements for long-term debt
2013	453,105
2014	453,105
2015	461,022
2016	358,105
2017	358,105
Future	1,235,562
Total long-term debt	3,319,004		2,123,127
Line of credit
Financing arrangements
Maximum borrowing capacity		13,500,000
Variable rate basis	three-month LIBOR
Interest rate margin on variable rate basis (as a percent)	2.75%
Interest rate (as a percent)	3.00%
Weighted-average interest rate (as a percent)	3.71%
Outstanding balance	7,923,487		9,345,044
Unused availability supported by entity's borrowing base	2,900,000
Real estate term note
Financing arrangements
Variable rate basis	three-month LIBOR
Interest rate margin on variable rate basis (as a percent)	3.25%
Interest rate (as a percent)	3.50%
Weighted-average interest rate (as a percent)	4.00%
Amount of monthly principal payments	10,000
Total long-term debt	1,707,894		1,009,050
Future maturity requirements for long-term debt
Total long-term debt	1,707,894		1,009,050
Increase in future maturity amount due to subsequent financing in 2013	112,000
Increase in future maturity amount due to subsequent financing in 2014	112,000
Increase in future maturity amount due to subsequent financing in 2015	1,450,000
Real estate term note maturing on March 31, 2027
Financing arrangements
Debt instrument, face amount		1,800,000
Real estate term note expiring on May 31, 2012
Financing arrangements
Debt instrument, face amount		900,000
Term loan
Financing arrangements
Long-term debt - net of current maturities	900,000
Term loan | Maximum
Financing arrangements
Debt instrument, face amount		2,000,000
Equipment term loan tied to equipment purchased in Mankato acquisition
Financing arrangements
Debt instrument, additional borrowing amount	1,700,000
Industrial revenue bond payable to the City of Blue Earth, Minnesota
Financing arrangements
Interest rate (as a percent)	0.30%
Amount of annual principal payments	80,000
Total long-term debt	520,000		600,000
Future maturity requirements for long-term debt
Total long-term debt	520,000		600,000
Equipment notes maturing in May 2015
Financing arrangements
Variable rate basis	three-month LIBOR
Interest rate margin on variable rate basis (as a percent)	4.50%
Interest rate (as a percent)	5.40%
Equipment notes maturing in December 2017
Financing arrangements
Variable rate basis	three-month LIBOR
Interest rate margin on variable rate basis (as a percent)	3.25%
Interest rate (as a percent)	4.10%
Equipment notes
Financing arrangements
Amount of monthly principal payments	21,000
Total long-term debt	1,091,110		514,077
Future maturity requirements for long-term debt
Total long-term debt	$ 1,091,110		$ 514,077