v3.19.3.a.u2
Cover Page - USD ($)
12 Months Ended
Oct. 31, 2019
Dec. 17, 2019
Apr. 30, 2019
Cover page.      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Oct. 31, 2019    
Document Transition Report false    
Entity File Number 1-8929    
Entity Registrant Name ABM INDUSTRIES INC    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 94-1369354    
Entity Address, Address Line One One Liberty Plaza    
Entity Address, Address Line Two 7th Floor    
Entity Address, City or Town New York    
Entity Address, State or Province NY    
Entity Address, Postal Zip Code 10006    
City Area Code 212    
Local Phone Number 297-0200    
Title of 12(b) Security Common Stock, $0.01 par value    
Trading Symbol ABM    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 2,498,832,469
Entity Common Stock, Shares Outstanding   66,589,257  
Entity Central Index Key 0000771497    
Current Fiscal Year End Date --10-31    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Amendment Flag false    
Documents Incorporated by Reference
Certain parts of the registrant’s Definitive Proxy Statement relating to the registrant’s 2020 Annual Meeting of Stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K.