Document and Entity Information	3 Months Ended
	Nov. 30, 2012	Jan. 09, 2013
Document Document And Entity Information [Abstract]
Document Type	10-Q/A
Amendment Flag	true
Amendment Description	This Amendment No. 1 reflects a correction in the presentation of the proceeds from the sale of by-products from the Company's manufacturing operations as sales rather than as a reduction of cost of sales in the Condensed Consolidated Statements of Operations. The Company has also corrected an error in the consolidated statements of cash flows to classify proceeds and payments related to a short term financing arrangement as a financing activity rather than as an operating activity.
Document Period End Date	Nov. 30, 2012
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q1
Trading Symbol	PENX
Entity Registrant Name	PENFORD CORP
Entity Central Index Key	0000739608
Current Fiscal Year End Date	--08-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		12,376,428