Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Apr. 30, 2016	Jul. 31, 2015
Property, Plant and Equipment [Line Items]
Total cost	$ 384,997	$ 348,868
Less accumulated depreciation	(129,476)	(114,823)
Property, plant and equipment, net	255,521	234,045
Land
Property, Plant and Equipment [Line Items]
Total cost	29,688	27,447
Building and Building Improvements
Property, Plant and Equipment [Line Items]
Total cost	239,678	214,462
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Total cost	$ 115,631	$ 106,959