Derivative Instruments - Additional Information (Detail) (Forward Contracts) In Millions, unless otherwise specified	12 Months Ended			12 Months Ended
	Jul. 31, 2014 USD ($)	Jul. 31, 2014 CAD	Jul. 31, 2013 CAD	Jul. 31, 2014 Cost of Revenue and Operating Expenses USD ($)	Jul. 31, 2013 Cost of Revenue and Operating Expenses USD ($)
Derivative [Line Items]
Notional amount of cash flow hedge instruments		0	6.7
Unrealized loss on cash flow hedges	(0.1)
Realized gain (loss) on cash flow hedge instruments				$ 0.2	$ (0.1)