Derivative Instruments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	May 31, 2013
Derivative [Line Items]
Interest rates, that would be reclassified to interest expense in the next 12 months	$ 1.2
Foreign Currency Forward Exchange Contracts
Derivative [Line Items]
Aggregate notional amount of foreign currency derivatives	58.9
Unrealized pre-tax gain (loss)	0.8
Interest Rate Swap
Derivative [Line Items]
Unrealized pre-tax gain (loss)	1.7
Notional amount of interest rate swap	$ 41.9
Maturity date	2014-03