Fair Value Measurements - Financial Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Apr. 30, 2016	Jul. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	$ 14,422	$ 16,041
Total Liabilities	802	1,280
Other Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	13,567	15,356
Prepaid expenses and other current assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Exchange Contracts	855	685
Other current liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Exchange Contracts	802	1,280
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	13,567	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	13,567	15,356
Fair Value, Inputs, Level 1 [Member] | Prepaid expenses and other current assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Exchange Contracts	0	0
Fair Value, Inputs, Level 1 [Member] | Other current liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Exchange Contracts	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	855	685
Total Liabilities	802	1,280
Fair Value, Inputs, Level 2 [Member] | Other Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	0
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 Exchange Contracts	855	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 Exchange Contracts	$ 802	$ 1,280