Fair Value Measurements - Financial Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Detail) (USD $)	12 Months Ended				3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended							3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended							3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013 Other Assets [Member]	Jul. 31, 2012 Other Assets [Member]	Jul. 31, 2012 Prepaid expenses and other current assets [Member]	Jul. 31, 2013 Prepaid expenses and other current assets [Member]	Jul. 31, 2012 Other current liabilities [Member]	Jul. 31, 2013 Other current liabilities [Member]	Jul. 31, 2013 Long term obligations less current maturities [Member]	Jul. 31, 2012 Long term obligations less current maturities [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 1 [Member]	Jul. 31, 2012 Fair Value, Inputs, Level 1 [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 1 [Member] Other Assets [Member]	Jul. 31, 2012 Fair Value, Inputs, Level 1 [Member] Other Assets [Member]	Jul. 31, 2012 Fair Value, Inputs, Level 1 [Member] Prepaid expenses and other current assets [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 1 [Member] Prepaid expenses and other current assets [Member]	Jul. 31, 2012 Fair Value, Inputs, Level 1 [Member] Other current liabilities [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 1 [Member] Other current liabilities [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 1 [Member] Long term obligations less current maturities [Member]	Jul. 31, 2012 Fair Value, Inputs, Level 1 [Member] Long term obligations less current maturities [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 2 [Member]	Jul. 31, 2012 Fair Value, Inputs, Level 2 [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 2 [Member] Other Assets [Member]	Jul. 31, 2012 Fair Value, Inputs, Level 2 [Member] Other Assets [Member]	Jul. 31, 2012 Fair Value, Inputs, Level 2 [Member] Prepaid expenses and other current assets [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 2 [Member] Prepaid expenses and other current assets [Member]	Jul. 31, 2012 Fair Value, Inputs, Level 2 [Member] Other current liabilities [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 2 [Member] Other current liabilities [Member]	Jul. 31, 2013 Fair Value, Inputs, Level 2 [Member] Long term obligations less current maturities [Member]	Jul. 31, 2012 Fair Value, Inputs, Level 2 [Member] Long term obligations less current maturities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities			$ 14,975,000	$ 12,676,000									$ 14,975,000	$ 12,676,000									$ 0	$ 0
Foreign exchange contracts	(150,000)	1,041,000			1,234,000	294,000	281,000	890,000							0	0	0	0							1,234,000	294,000	281,000	890,000
Total Assets	15,269,000	13,910,000									14,975,000	12,676,000									294,000	1,234,000
Foreign currency denominated debt									103,635,000	99,081,000									0	0									103,635,000	99,081,000
Total Liabilities	$ 104,525,000	$ 99,362,000									$ 0	$ 0									$ 104,525,000	$ 99,362,000