Risk Management - Fixed Price Forward Contracts (Detail) - Forward Contracts [Member] - Sales Contracts [Member]	9 Months Ended
Jun. 30, 2016 USD ($) lb T gal
Ethanol (Gallons) [Member]
Derivative [Line Items]
Forward contracts, Quantity \| gal	2,592,000
Forward contracts, Amount	$ 3,867,000
Forward contracts, Period Covered Through	Jul. 31, 2016
Distillers Grains (Tons) [Member]
Derivative [Line Items]
Forward contracts, Quantity \| T	14,412
Forward contracts, Quantity \| T	14,412
Forward contracts, Amount	$ 946,000
Forward contracts, Period Covered Through	Jul. 31, 2016
Corn Oil (Pounds) [Member]
Derivative [Line Items]
Forward contracts, Quantity \| lb	799,000
Forward contracts, Quantity \| lb	799,000
Forward contracts, Amount	$ 189,000
Forward contracts, Period Covered Through	Jul. 31, 2016

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Date the derivative contract matures, in CCYY-MM-DD format.

+ References

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- Definition

Nominal mass used to calculate payments on a derivative instrument.

+ References

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- Definition

Nominal volume used to calculate payments on a derivative instrument.

+ References

No definition available.

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