Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	May 31, 2014	May 31, 2013	May 31, 2014	May 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense of intangible assets	$ 6,272,000	$ 5,539,000	$ 18,713,000	$ 17,542,000
Future amortization expense, remainder of 2014	6,500,000		6,500,000
Future amortization expense, 2015	25,800,000		25,800,000
Future amortization expense, 2016	25,800,000		25,800,000
Future amortization expense, 2017	25,100,000		25,100,000
Future amortization expense, 2018	24,300,000		24,300,000
Future amortization expense, 2019	24,100,000		24,100,000
Future amortization expense, thereafter	$ 117,300,000		$ 117,300,000