Derivatives and Hedging Activities - Additional Information (Detail) £ in Thousands, $ in Thousands	3 Months Ended
	Oct. 31, 2016 USD ($)	Oct. 31, 2015 USD ($)	Oct. 31, 2016 GBP (£)	Jul. 31, 2016 USD ($)	May 13, 2010 GBP (£)
Summary
Derivative maturity	18 months
Derivative, Notional Amount	$ 148,769			$ 186,093
Summary of Cash Flow Hedge Activity
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	58	$ 420
Cash Flow Hedge Gain (Loss) Reclassified from OCI to Earnings	405	(457)
Total Outstanding Forward Foreign Exchange Contracts	25,915
Summary of Derivative Instruments Not Designated as Hedging Instruments
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ 1,733	$ (413)
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