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Income Taxes - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified |
3 Months Ended | ||
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Nov. 30, 2014
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Nov. 30, 2013
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Aug. 31, 2014
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| Income Tax Disclosure [Abstract] | |||
| Effective income tax rate | 24.00%us-gaap_EffectiveIncomeTaxRateContinuingOperations | 7.70%us-gaap_EffectiveIncomeTaxRateContinuingOperations | |
| Discrete item | $ 7.3atu_Discreteitem | ||
| Gross liability for unrecognized tax benefits, excluding interest and penalties | 32.8us-gaap_UnrecognizedTaxBenefits | 32.3us-gaap_UnrecognizedTaxBenefits | |
| Liabilities for payment of interest and penalties related to its unrecognized tax benefits | $ 2.2us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued | $ 2.0us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued | |
| X | ||||||||||
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- Definition
Discrete item No definition available.
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- Definition
Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Definition
Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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