Subsequent Events	9 Months Ended
Jul. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS Acquisition of GCA Services Group On September 1, 2017, we acquired GCA Holding Corp., the parent company of GCA Services Group (“GCA”), from affiliates of Thomas H. Lee Partners, L.P., Goldman Sachs Merchant Banking Division, and other GCA shareholders. GCA is a provider of integrated facility services to educational institutions and commercial facilities. We acquired this business for approximately $1.25 billion, consisting of $851.0 million in cash, subject to certain adjustments as set forth in the Merger Agreement, and approximately 9.5 million shares of ABM common stock. As a result of this transaction, affiliates of Thomas H. Lee Partners, L.P. and Goldman Sachs Merchant Banking Division own, in the aggregate, approximately 14% of our outstanding shares. Due to the timing of the acquisition and subsequent integration of GCA’s standalone operations, GCA will be separately managed and reported for the fourth quarter of 2017. We will begin to integrate GCA into our industry group model in the first quarter of 2018. While we are currently evaluating the impact of this acquisition on our reportable segments, we anticipate our Education industry group will become a reportable segment in the first quarter of 2018. We will account for this acquisition under the acquisition method of accounting. The accounting for this acquisition was incomplete at the time the Financial Statements were issued. Credit Facility In connection with the GCA acquisition, we refinanced and replaced our 2010 Facility with a new syndicated secured credit facility (the “New Credit Facility”) consisting of a $900 million revolving credit facility and an $800 million amortizing term loan with a five-year term. The revolving credit facility reduces to $800 million after one year and has an expiration date of September 1, 2022. The interest rate on the revolving credit facility and the term loan is 1-month LIBOR plus a spread that is based upon our leverage ratio. The spread ranges from 1.00% to 2.25% for Eurocurrency loans and zero to 1.25% for base rate loans. We also pay a commitment fee, ranging from 0.200% to 0.350%, based upon our leverage ratio, on the average daily unused portion of the revolving credit facility. Financial covenants under the New Credit Facility include a maximum leverage ratio of 4.75 to 1.0, which adjusts to 3.50 to 1.0 by July 2020, and a minimum fixed charge ratio of 1.50 to 1.0. We expect to be in compliance with the covenants under the New Credit Facility. The obligations under the New Credit Facility are guaranteed by the material, domestic wholly owned subsidiaries of ABM, and are secured by a pledge of substantially all of the existing and future property and assets of ABM and the subsidiary guarantors, including a pledge of the capital stock of the domestic subsidiaries of ABM and 65% of the capital stock of certain foreign subsidiaries held by ABM and the subsidiary guarantors, subject to certain exceptions. Hurricane Harvey Hurricane Harvey made landfall near Corpus Christi, Texas, on Friday, August 25, 2017 and also impacted the Houston area as a tropical storm with significant rain and flooding. The impact of Hurricane Harvey on our business is currently unknown, as the flooding it caused has disrupted operations at our Shared Services Center in Sugar Land, Texas, and impacted services we provide to clients in the Houston area, and the timeframe to resume operations and provision of services to impacted clients is uncertain. We have begun to mobilize continuity plans and set up both satellite and regional offices to minimize Hurricane Harvey’s impact on our business processes.

SUBSEQUENT EVENTS

Acquisition of GCA Services Group

On September 1, 2017, we acquired GCA Holding Corp., the parent company of GCA Services Group (“GCA”), from affiliates of Thomas H. Lee Partners, L.P., Goldman Sachs Merchant Banking Division, and other GCA shareholders. GCA is a provider of integrated facility services to educational institutions and commercial facilities. We acquired this business for approximately $1.25 billion, consisting of $851.0 million in cash, subject to certain adjustments as set forth in the Merger Agreement, and approximately 9.5 million shares of ABM common stock. As a result of this transaction, affiliates of Thomas H. Lee Partners, L.P. and Goldman Sachs Merchant Banking Division own, in the aggregate, approximately 14% of our outstanding shares.

Due to the timing of the acquisition and subsequent integration of GCA’s standalone operations, GCA will be separately managed and reported for the fourth quarter of 2017. We will begin to integrate GCA into our industry group model in the first quarter of 2018. While we are currently evaluating the impact of this acquisition on our reportable segments, we anticipate our Education industry group will become a reportable segment in the first quarter of 2018.

We will account for this acquisition under the acquisition method of accounting. The accounting for this acquisition was incomplete at the time the Financial Statements were issued.

Credit Facility

In connection with the GCA acquisition, we refinanced and replaced our 2010 Facility with a new syndicated secured credit facility (the “New Credit Facility”) consisting of a $900 million revolving credit facility and an $800 million amortizing term loan with a five-year term. The revolving credit facility reduces to $800 million after one year and has an expiration date of September 1, 2022.

The interest rate on the revolving credit facility and the term loan is 1-month LIBOR plus a spread that is based upon our leverage ratio. The spread ranges from 1.00% to 2.25% for Eurocurrency loans and zero to 1.25% for base rate loans. We also pay a commitment fee, ranging from 0.200% to 0.350%, based upon our leverage ratio, on the average daily unused portion of the revolving credit facility.

Financial covenants under the New Credit Facility include a maximum leverage ratio of 4.75 to 1.0, which adjusts to 3.50 to 1.0 by July 2020, and a minimum fixed charge ratio of 1.50 to 1.0. We expect to be in compliance with the covenants under the New Credit Facility.

The obligations under the New Credit Facility are guaranteed by the material, domestic wholly owned subsidiaries of ABM, and are secured by a pledge of substantially all of the existing and future property and assets of ABM and the subsidiary guarantors, including a pledge of the capital stock of the domestic subsidiaries of ABM and 65% of the capital stock of certain foreign subsidiaries held by ABM and the subsidiary guarantors, subject to certain exceptions.

Hurricane Harvey

Hurricane Harvey made landfall near Corpus Christi, Texas, on Friday, August 25, 2017 and also impacted the Houston area as a tropical storm with significant rain and flooding. The impact of Hurricane Harvey on our business is currently unknown, as the flooding it caused has disrupted operations at our Shared Services Center in Sugar Land, Texas, and impacted services we provide to clients in the Houston area, and the timeframe to resume operations and provision of services to impacted clients is uncertain. We have begun to mobilize continuity plans and set up both satellite and regional offices to minimize Hurricane Harvey’s impact on our business processes.