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Fair Value Measurements and Derivative Instruments - Fair Value of Company's Derivative by Contract Type (Detail) (USD $)
In Thousands, unless otherwise specified |
Nov. 30, 2012
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Aug. 31, 2012
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|---|---|---|
| Derivatives, Fair Value [Line Items] | ||
| Assets Fair Value | $ 88 | $ 12 |
| Liabilities Fair Value | 495 | 1,434 |
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Corn Futures [Member] | Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Other Current Assets [Member] | Commodity Contract [Member]
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| Derivatives, Fair Value [Line Items] | ||
| Assets Fair Value | 88 | 12 |
| Liabilities Fair Value | 126 | |
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Corn Futures [Member] | Fair Value Hedging [Member] | Designated as Hedging Instrument [Member] | Other Current Assets [Member] | Commodity Contract [Member]
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| Derivatives, Fair Value [Line Items] | ||
| Assets Fair Value | ||
| Liabilities Fair Value | 238 | 602 |
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Ethanol Futures [Member] | Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Other Current Assets [Member] | Commodity Contract [Member]
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| Derivatives, Fair Value [Line Items] | ||
| Assets Fair Value | ||
| Liabilities Fair Value | 57 | 706 |
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Natural Gas Futures [Member] | Not Designated as Hedging Instrument [Member] | Other Current Assets [Member] | Commodity Contract [Member]
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| Derivatives, Fair Value [Line Items] | ||
| Assets Fair Value | ||
| Liabilities Fair Value | $ 200 |