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Stock-based Compensation Plans - Schedule of Share Based Payment Award Stock Options Valuation Assumptions (Detail) (Stock Options [Member], USD $)
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12 Months Ended | |
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Aug. 31, 2012
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Aug. 31, 2011
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Stock Options [Member]
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Expected volatility | 68.00% | 71.00% |
| Expected life (years) | 4 years 10 months 24 days | 4 years 3 months 18 days |
| Interest rate, Minimum | 0.50% | 1.10% |
| Interest rate, Maximum | 1.10% | 2.80% |
| Dividend yield | 0.00% | 0.00% |
| Weighted-average fair values, Per share | $ 3.13 | $ 3.62 |