Quarterly report pursuant to Section 13 or 15(d)

Goodwill and Other Intangible Assets - Additional Information (Detail)

v2.4.1.9
Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)
 3 Months Ended
Nov. 30, 2014
Nov. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]    
Amortization expense of intangible assets $ 6,286,000us-gaap_AmortizationOfIntangibleAssets $ 6,215,000us-gaap_AmortizationOfIntangibleAssets
Future amortization expense, remainder of 2015 18,400,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear  
Future amortization expense, 2016 24,400,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo  
Future amortization expense, 2017 23,400,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree  
Future amortization expense, 2018 23,100,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour  
Future amortization expense, 2019 22,900,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive  
Future amortization expense, 2020 22,200,000atu_FiniteLivedIntangibleAssetsAmortizationExpenseYearSix  
Future amortization expense, thereafter $ 89,800,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive