Nature of Business and Significant Accounting Policies Revenue by Product (Details) (USD $)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Revenue from External Customer [Line Items]
Revenues (Notes 1 and 8)	$ 182,469,541	$ 169,567,374	$ 173,951,126
Ethanol [Member]
Revenue from External Customer [Line Items]
Revenues (Notes 1 and 8)	133,228,000	126,440,000	139,536,000
Distiller's Grain [Member]
Revenue from External Customer [Line Items]
Revenues (Notes 1 and 8)	45,047,000	38,564,000	31,716,000
Other [Member]
Revenue from External Customer [Line Items]
Revenues (Notes 1 and 8)	$ 4,182,000	$ 4,570,000	$ 3,826,000