Components of Income Tax Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended																						12 Months Ended
	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012		Oct. 31, 2011		Jul. 31, 2011		Apr. 30, 2011		Jan. 31, 2011		Oct. 31, 2010		Jul. 31, 2010		Apr. 30, 2010		Jan. 31, 2010		Oct. 31, 2009		Jul. 31, 2012	Jul. 31, 2011		Jul. 31, 2010		Jul. 31, 2009
Deferred Tax Liability Not Recognized [Line Items]
Income tax expense from continuing operations																							$ 3,035	$ 819	[1]	$ 5,162	[1]	$ 10,831	[1]
Discontinued operations																									[1]				[1]
Other comprehensive income																										43		(529)	[1]
Total income tax expense	$ 1,985	$ (1,202)	$ 380	[1]	$ 1,871	[1]	$ (2,954)	[1]	$ 1,331	[1]	$ 1,132	[1]	$ 1,309	[1]	$ 165	[1]	$ 942	[1]	$ 2,174	[1]	$ 1,881	[1]	$ 3,035	$ 819	[1]	$ 5,205		$ 10,302	[1]

[1] As Restated