Derivatives and Hedging Activities - Additional Information (Detail) £ in Thousands, $ in Thousands	3 Months Ended
	Oct. 31, 2015 USD ($)	Oct. 31, 2014 USD ($)	Oct. 31, 2015 GBP (£)	Jul. 31, 2015 USD ($)	May. 13, 2010 GBP (£)
Summary
Derivative maturity	18 months
Derivative, Notional Amount	$ 126,945			$ 139,300
Summary of Cash Flow Hedge Activity
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	420	$ (601)
Cash Flow Hedge Gain (Loss) Reclassified from OCI to Earnings	(457)	21
Total Outstanding Forward Foreign Exchange Contracts	24,920
Summary of Derivative Instruments Not Designated as Hedging Instruments
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ 413	$ (841)
GBP-denominated interco debt [Member]
Summary of Net Investment Hedge Activity
Net investment hedges to hedge portions of net investment | £			£ 25,036
Senior Unsecured Notes [Member]
Summary of Net Investment Hedge Activity
Net investment hedges to hedge portions of net investment | £					£ 75,000