Document and Entity Information - shares	9 Months Ended
	Jul. 31, 2017	Aug. 29, 2017
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jul. 31, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q3
Trading Symbol	GEF
Entity Registrant Name	GREIF INC
Entity Central Index Key	0000043920
Current Fiscal Year End Date	--10-31
Entity Filer Category	Large Accelerated Filer
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		25,835,281
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		22,007,725