Schedule of Deferred Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2012	Jul. 31, 2011
Schedule of Components of Deferred Tax Provision [Line Items]
Inventory basis	$ (589)	$ (251)
Employee benefits	2,026	3,102
Self-insurance reserves	8,556	8,036
Accrued product warranties	26,690	24,443
Accrued incentives	2,369	2,948
Sales returns and allowances	1,145	1,231
Accrued expenses	1,399	2,938
Unrecognized tax benefits	963	597
Other	(1,662)	(1,456)
Total current net deferred tax asset	40,897	41,588
Property basis	(4,482)	(5,166)
Investments	(433)	(898)
Deferred compensation	5,069	4,836
Intangibles	(35,524)	(37,513)
Unrecognized tax benefits	14,436	13,882
Total net long-term deferred tax liability	(20,934)	(24,859)
Net deferred tax asset	$ 19,963	$ 16,729