Document and Entity Information - shares	9 Months Ended
	May 31, 2016	Jun. 30, 2016
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	May 31, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q3
Trading Symbol	GBX
Entity Registrant Name	GREENBRIER COMPANIES INC
Entity Central Index Key	0000923120
Current Fiscal Year End Date	--08-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		28,204,389