Goodwill and Other Intangibles - Schedule of Other Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011
Intangible Assets Goodwill And Other Assets [Line Items]
Weighted Average Amortization Period	6 years 2 months 12 days	6 years 2 months 12 days
Gross Carrying Amount	$ 5,180	$ 5,363
Accumulated Amortization	(3,273)	(2,702)
Net Balance	1,907	2,661
Trademarks And Patents [Member]
Intangible Assets Goodwill And Other Assets [Line Items]
Weighted Average Amortization Period	5 years	5 years
Gross Carrying Amount	2,026	2,026
Accumulated Amortization	(1,386)	(1,052)
Net Balance	640	974
Customer Lists [Member]
Intangible Assets Goodwill And Other Assets [Line Items]
Weighted Average Amortization Period	7 years 1 month 6 days	7 years 2 months 12 days
Gross Carrying Amount	3,154	3,154
Accumulated Amortization	(1,887)	(1,522)
Net Balance	1,267	1,632
Others [Member]
Intangible Assets Goodwill And Other Assets [Line Items]
Weighted Average Amortization Period		3 years
Gross Carrying Amount		183
Accumulated Amortization		(128)
Net Balance		$ 55