Legal Proceedings and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended		3 Months Ended	12 Months Ended	1 Months Ended		12 Months Ended
	Aug. 31, 2013 Defendant	Apr. 30, 2012 Patents	May 31, 2013	Aug. 31, 2013	Aug. 31, 2013 Penford Products [Member]	Aug. 31, 2013 Carolina Starches, LLC [Member]	Aug. 31, 2012 Australia and New Zealand Discontinued Operations [Member]	Aug. 31, 2010 Australia and New Zealand Discontinued Operations [Member]
Loss Contingencies [Line Items]
Number of patents under allegation of patent infringement		2
Amount of recovery sought in complaint					$ 778,000	$ 216,000
Number of defendant	2
Name of defendants	Penford Products and Carolina Starches, LLC
Name of plaintiff	Pirinate Consulting Group, LLC
Litigation settlement receivable amount			3,400,000
Litigation settlement receivable net of litigation expenses			2,100,000	2,106,000
Litigation settlement expenses			300,000
Amount of proceeds in escrow								2,000,000
Escrowed payments received							1,225,000
Amount of claim filed by the purchaser of Company's Lane cave							$ 901,000