Quarterly report pursuant to Section 13 or 15(d)

Goodwill and Other Intangible Assets - Additional Information (Details)

v2.4.1.9
Goodwill and Other Intangible Assets - Additional Information (Details) (USD $)
 3 Months Ended 6 Months Ended
Feb. 28, 2015
Feb. 28, 2014
Feb. 28, 2015
Feb. 28, 2014
Aug. 31, 2014
Goodwill [Line Items]          
Impairment charge $ 84,353,000us-gaap_AssetImpairmentCharges $ 0us-gaap_AssetImpairmentCharges $ 84,353,000us-gaap_AssetImpairmentCharges $ 0us-gaap_AssetImpairmentCharges  
Goodwill Impairment Charge 78,000,000us-gaap_GoodwillImpairmentLoss   78,530,000us-gaap_GoodwillImpairmentLoss    
Goodwill 615,953,000us-gaap_Goodwill   615,953,000us-gaap_Goodwill   742,770,000us-gaap_Goodwill
Future Amortization Expense, Remainder of 2015 11,900,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear   11,900,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear    
Future Amortization Expense, 2016 23,800,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo   23,800,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo    
Future Amortization Expense, 2017 22,800,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree   22,800,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree    
Future Amortization Expense, 2018 22,500,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour   22,500,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour    
Future Amortization Expense, 2019 22,300,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive   22,300,000us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive    
Future Amortization Expense, 2020 21,600,000atu_FiniteLivedIntangibleAssetsAmortizationExpenseYearSix   21,600,000atu_FiniteLivedIntangibleAssetsAmortizationExpenseYearSix    
Future Amortization Expense, Thereafter 86,700,000atu_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearSix   86,700,000atu_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearSix    
Viking [Member]          
Goodwill [Line Items]          
Goodwill 41,900,000us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= atu_VikingMember 		  41,900,000us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= atu_VikingMember 		   
Cortland [Member]          
Goodwill [Line Items]          
Goodwill 77,500,000us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= atu_CortlandMember 		  77,500,000us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= atu_CortlandMember 		   
Energy          
Goodwill [Line Items]          
Goodwill Impairment Charge     78,530,000us-gaap_GoodwillImpairmentLoss
/ us-gaap_StatementBusinessSegmentsAxis
= atu_EnergyMember 		   
Goodwill 242,540,000us-gaap_Goodwill
/ us-gaap_StatementBusinessSegmentsAxis
= atu_EnergyMember 		  242,540,000us-gaap_Goodwill
/ us-gaap_StatementBusinessSegmentsAxis
= atu_EnergyMember 		  350,627,000us-gaap_Goodwill
/ us-gaap_StatementBusinessSegmentsAxis
= atu_EnergyMember
Tradenames          
Goodwill [Line Items]          
Impairment of Intangible Assets (Excluding Goodwill) $ 6,400,000us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill
/ us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_TradeNamesMember