Property, Plant and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2015	Jul. 31, 2014
Property, Plant and Equipment [Line Items]
Total cost	$ 290,325	$ 273,501
Less accumulated depreciation	(107,168)	(103,639)
Property, plant and equipment, net	183,157	169,862
Land
Property, Plant and Equipment [Line Items]
Total cost	24,541	21,592
Building and Building Improvements
Property, Plant and Equipment [Line Items]
Total cost	188,738	175,611
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Total cost	$ 77,046	$ 76,298