Components of Income Tax Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
Income Tax Expense Benefit [Line Items]
Income tax expense from continuing operations	$ 1,804	$ 392	$ 674	$ 909	$ 1,986	$ (1,202)	$ 380	$ 1,871	$ 3,779	$ 3,035	$ 819
Total income tax expense									$ 3,779	$ 3,035	$ 819