Long-Term Debt (Details) (USD $)	0 Months Ended
	Nov. 08, 2012	Aug. 20, 2012	Jun. 30, 2013		Sep. 30, 2012
Debt Instrument [Line Items]
Revolving term loan	$ 11,000,000		$ 0	[1]	$ 3,237,000	[1]
Note payable to Iowa Department of Transportation			187,053	[2]	238,021	[2]
Long-term debt, total			187,053		3,475,021
Less current maturities			(25,888)		(50,968)
Long-term debt, less current maturities			161,165		3,424,053
Debt instrument, description of variable rate basis	LIBOR
Debt instrument, basis spread on variable rate	4.00%
Line of credit facility, unused capacity, commitment fee percentage		0.60%
Railroad revolving loan fund			$ 500,000
Debt instrument, interest rate, stated percentage			2.11%

[1] The Company entered into a new master loan agreement with a financial institution on August 21, 2012. One of the supplements of the agreement is a revolving term loan available for up to $11,000,000. This supplement amends and restates the supplement dated November 8, 2012. The revolving term loan is to provide working capital to the Company and to finance construction projects related to conversion to natural gas. The Company will pay interest on the unpaid balance at a variable interest rate (adjusted on a weekly basis) based upon the one-month LIBOR index rate plus 4.00%. The Company will also pay a commitment fee on the average daily unused portion of the loan at the rate of .60% per annum, payable monthly. The loan is secured by substantially all assets of the Company and subject to certain financial and nonfinancial covenants as defined in the master loan agreement. The term of the loan will expire, and the Company must pay all unpaid principal amounts outstanding under the revolving term loan, on November 1, 2019.

[2] The Company entered into a $500,000 loan agreement with the Iowa Department of Transportation (IDOT) in February 2005. The proceeds were disbursed upon submission of paid invoices. Interest at 2.11% began accruing on January 1, 2007. Principal payments will be due semiannually through July 2016. The loan is secured by all rail track material constructed as part of the plant construction. The debt is subordinate to the above financial institution revolving term loan (A) and revolving credit loan (Note 4.)