Property, Plant and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2014	Jul. 31, 2013
Property, Plant and Equipment [Line Items]
Land	$ 19,896	$ 20,885
Buildings and improvements	155,315	150,628
Machinery and equipment	79,764	73,478
Total cost	254,975	244,991
Less accumulated depreciation	106,006	101,182
Net property, plant and equipment	$ 148,969	$ 143,809