Quarterly report pursuant to Section 13 or 15(d)

Goodwill and Other Intangible Assets - Additional Information (Detail)

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Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)
 3 Months Ended
Nov. 30, 2012
Nov. 30, 2011
Finite-Lived Intangible Assets [Line Items]    
Amortization expense of intangible assets $ 7,854,000 $ 7,218,000
Future amortization expense, 2013 22,000,000  
Future amortization expense, 2014 28,100,000  
Future amortization expense, 2015 28,000,000  
Future amortization expense, 2016 27,900,000  
Future amortization expense, 2017 26,700,000  
Future amortization expense, 2018 26,300,000  
Future amortization expense, thereafter $ 143,200,000