Foreign Currency Contracts - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2016	Jan. 31, 2015
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Foreign currency exchange gains (losses)	$ (179)	$ 1,726	$ (753)	$ 2,430
Foreign Exchange Contract
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, notional amount	7,300		7,300
Foreign currency exchange gains (losses)	(400)	$ (800)	(100)	$ (1,100)
Foreign Exchange Contract | Other Current Liabilities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative liability, notional amount	$ 100		$ 100