Property, Plant and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Oct. 31, 2014	Jul. 31, 2014	Oct. 31, 2013
Property, Plant and Equipment [Abstract]
Land and improvements	$ 11,185	$ 11,622	$ 10,166
Buildings and improvements	59,659	59,260	57,348
Machinery, equipment and software	215,155	217,159	214,150
Construction in progress	21,955	16,368	2,838
Capital leases	16,539	16,678	16,343
Total	324,493	321,087	300,845
Less: accumulated depreciation	(186,423)	(184,088)	(169,389)
Less: accumulated amortization	(5,073)	(5,108)	(2,966)
Property, plant and equipment, net	$ 132,997	$ 131,891	$ 128,490