Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Apr. 30, 2017	Jul. 31, 2016
Property, Plant and Equipment [Line Items]
Total cost	$ 553,040	$ 480,436
Less accumulated depreciation	(158,222)	(136,169)
Property, plant and equipment, net	394,818	344,267
Land
Property, Plant and Equipment [Line Items]
Total cost	48,553	46,422
Building and Building Improvements
Property, Plant and Equipment [Line Items]
Total cost	349,335	300,902
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Total cost	$ 155,152	$ 133,112