Foreign Currency Contracts - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2015	Apr. 30, 2014
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Foreign currency exchange gains (losses)	$ (84,000)	$ (537,000)	$ 2,346,000	$ (707,000)
Foreign Exchange Contract
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, notional amount	9,865,000		9,865,000
Foreign currency exchange gains (losses)	500,000		(600,000)
Foreign Exchange Contract | Other Current Liabilities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative liability, notional amount	$ 400,000		$ 400,000