Document and Entity Information Document - shares	6 Months Ended
	Feb. 29, 2016	Apr. 01, 2016
Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Feb. 29, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q2
Entity Registrant Name	SCHNITZER STEEL INDUSTRIES INC
Entity Central Index Key	0000912603
Current Fiscal Year End Date	--08-31
Entity Filer Category	Accelerated Filer
Class A Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		26,450,095
Class B Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		305,900