Goodwill and Other Intangible Assets - Carrying Amount and Accumulated Amortization of Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Aug. 31, 2012	Aug. 31, 2011
Acquired Finite-Lived Intangible Assets [Line Items]
Carrying Amount	$ 2,038	$ 1,768
Accumulated Amortization	1,571	1,436
Patents [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Carrying Amount	1,748	1,768
Accumulated Amortization	1,500	1,436
Customer Lists [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Carrying Amount	190
Accumulated Amortization	59
Non-Compete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Carrying Amount	100
Accumulated Amortization	$ 12