Document and Entity Information	3 Months Ended
	Dec. 31, 2012	Jan. 22, 2013
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Dec. 31, 2012
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q1
Trading Symbol	BRKS
Entity Registrant Name	BROOKS AUTOMATION INC
Entity Central Index Key	0000933974
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		66,345,436