Information for Pension Plans with an Accumulated Benefit Obligation in Excess of Plan Assets (Detail) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 2,064	$ 2,047	$ 1,991
Accumulated benefit obligation	1,290	1,241	1,171
Fair value of plan assets	$ 1,024	$ 1,018	$ 875