Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Apr. 30, 2018	Jul. 31, 2017
Property, Plant and Equipment [Line Items]
Total cost	$ 683,067	$ 590,675
Less accumulated depreciation	(192,453)	(165,437)
Property, plant and equipment, net	490,614	425,238
Land
Property, Plant and Equipment [Line Items]
Total cost	55,749	48,812
Building and Building Improvements
Property, Plant and Equipment [Line Items]
Total cost	440,206	380,139
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Total cost	$ 187,112	$ 161,724