Document and Entity Information - USD ($)	12 Months Ended
	Oct. 31, 2015	Dec. 09, 2015	Apr. 30, 2015
Document And Entity Information [Abstract]
Entity Registrant Name	ABM INDUSTRIES INC /DE/
Entity Central Index Key	0000771497
Current Fiscal Year End Date	--10-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Oct. 31, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Trading Symbol	ABM
Amendment Flag	false
Entity Common Stock, Shares Outstanding		56,071,902
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 1,781,044,870