Quarterly report pursuant to Section 13 or 15(d)

Changes in Carrying Value of Goodwill (Detail)

v2.4.1.9
Changes in Carrying Value of Goodwill (Detail) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended
Nov. 30, 2014
Goodwill [Roll Forward]  
Balance as of August 31, 2014 $ 742,770us-gaap_Goodwill
Purchase accounting adjustments (3,157)us-gaap_GoodwillPurchaseAccountingAdjustments
Impact of changes in foreign currency rates (24,657)us-gaap_GoodwillTranslationAdjustments
Balance as of November 30, 2014 714,956us-gaap_Goodwill
Industrial  
Goodwill [Roll Forward]  
Balance as of August 31, 2014 100,266us-gaap_Goodwill
/ us-gaap_StatementBusinessSegmentsAxis
= atu_IndustrialMember
Purchase accounting adjustments (3,157)us-gaap_GoodwillPurchaseAccountingAdjustments
/ us-gaap_StatementBusinessSegmentsAxis
= atu_IndustrialMember
Impact of changes in foreign currency rates (1,827)us-gaap_GoodwillTranslationAdjustments
/ us-gaap_StatementBusinessSegmentsAxis
= atu_IndustrialMember
Balance as of November 30, 2014 95,282us-gaap_Goodwill
/ us-gaap_StatementBusinessSegmentsAxis
= atu_IndustrialMember
Energy  
Goodwill [Roll Forward]  
Balance as of August 31, 2014 350,627us-gaap_Goodwill
/ us-gaap_StatementBusinessSegmentsAxis
= atu_EnergyMember
Purchase accounting adjustments 0us-gaap_GoodwillPurchaseAccountingAdjustments
/ us-gaap_StatementBusinessSegmentsAxis
= atu_EnergyMember
Impact of changes in foreign currency rates (18,626)us-gaap_GoodwillTranslationAdjustments
/ us-gaap_StatementBusinessSegmentsAxis
= atu_EnergyMember
Balance as of November 30, 2014 332,001us-gaap_Goodwill
/ us-gaap_StatementBusinessSegmentsAxis
= atu_EnergyMember
Engineered Solutions  
Goodwill [Roll Forward]  
Balance as of August 31, 2014 291,877us-gaap_Goodwill
/ us-gaap_StatementBusinessSegmentsAxis
= atu_EngineeredSolutionsMember
Purchase accounting adjustments 0us-gaap_GoodwillPurchaseAccountingAdjustments
/ us-gaap_StatementBusinessSegmentsAxis
= atu_EngineeredSolutionsMember
Impact of changes in foreign currency rates (4,204)us-gaap_GoodwillTranslationAdjustments
/ us-gaap_StatementBusinessSegmentsAxis
= atu_EngineeredSolutionsMember
Balance as of November 30, 2014 $ 287,673us-gaap_Goodwill
/ us-gaap_StatementBusinessSegmentsAxis
= atu_EngineeredSolutionsMember