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Income Taxes - Additional Information (Detail) (USD $)
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3 Months Ended | |
|---|---|---|
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Nov. 30, 2012
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Nov. 30, 2011
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| Income Tax Disclosure [Abstract] | ||
| Effective tax rate for the first quarter | 38.50% | 70.00% |
| State income taxes and dividends and accretion of discount | 15.00% | |
| Valuation allowance | $ 1,800,000 | |
| Tax credit carryforwards related to expiration period | Aug. 31, 2014 | |
| Net deferred tax assets | 13,300,000 | |
| Accrued interest and penalties included in long-term tax liability | 200,000 | |
| Liability increase relating to unrecognized tax benefits, interest | 43,000 | |
| Liability increase relating to unrecognized tax benefits, penalties | $ 1,100,000 | |