Operating Results of Discontinued Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales			$ 83,903
Operating income (loss) of discontinued operations	$ (2,417)	$ (4,791)	(5,735)
Pre-tax gain on disposal of discontinued business			7,079
Income (loss) before income taxes	(2,417)	(4,791)	1,344
Income tax benefit	914	2,167	2,142
Income (loss) from discontinued operations, net of income taxes	$ (1,503)	$ (2,624)	$ 3,486