Fair Value Measurements - Financial Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended					3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended							3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jul. 31, 2013	Jan. 31, 2014 Other Assets [Member]	Jul. 31, 2013 Other Assets [Member]	Jul. 31, 2013 Prepaid expenses and other current assets [Member]	Jan. 31, 2014 Prepaid expenses and other current assets [Member]	Jul. 31, 2013 Other current liabilities [Member]	Jan. 31, 2014 Other current liabilities [Member]	Jan. 31, 2014 Fair Value, Inputs, Level 1 [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 1 [Member]	Jan. 31, 2014 Fair Value, Inputs, Level 1 [Member] Other Assets [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 1 [Member] Other Assets [Member]	Jan. 31, 2014 Fair Value, Inputs, Level 2 [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 2 [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 2 [Member] Prepaid expenses and other current assets [Member]	Jan. 31, 2014 Fair Value, Inputs, Level 2 [Member] Prepaid expenses and other current assets [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 2 [Member] Other current liabilities [Member]	Jan. 31, 2014 Fair Value, Inputs, Level 2 [Member] Other current liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities				$ 15,043	$ 14,975							$ 15,043	$ 14,975
Foreign exchange contracts	280	367				294	612	890	563							294	612	890	563
Total Assets	15,655		15,269							15,043	14,975			612	294
Total Liabilities	$ 563		$ 890											$ 563	$ 890