Fair Value Measurements - Financial Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jul. 31, 2016	Jul. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	$ 15,972	$ 16,041
Total Liabilities	738	1,280
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	13,834	15,356
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	13,834	15,356
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	2,138	685
Total Liabilities	738	1,280
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	2,138	685
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	$ 738	$ 1,280