Operating Results of Discontinued Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended		12 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Oct. 31, 2013	Jan. 31, 2015	Jan. 31, 2014	Jul. 31, 2014
Discontinued Operations:
Net sales					$ 83,903
Operating loss of discontinued operations	(2,564)	(1,131)		(2,999)	(4,564)
Pre-tax gain (loss) on disposal of discontinued business		(746)	7,825		7,079	7,079
Income (loss) before income taxes	(2,564)	(1,877)		(2,999)	2,515
Income tax benefit	(945)	(851)		(1,104)	(1,173)
Income (loss) from discontinued operations, net of taxes	$ (1,619)	$ (1,026)		$ (1,895)	$ 3,688