Fair Value Measurements - Financial Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jul. 31, 2015	Jul. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	$ 16,041	$ 16,128
Total Liabilities	1,280	389
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	15,356	15,962
Total Liabilities	0	0
Fair Value, Inputs, Level 1 [Member] | Other assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	15,356	15,962
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	685	166
Total Liabilities	1,280	389
Fair Value, Inputs, Level 2 [Member] | Prepaid expenses and other current assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	685	166
Fair Value, Inputs, Level 2 [Member] | Other current liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contracts, Liability, Fair Value Disclosure	$ 1,280	$ 389