Basis of Presentation and Significant Accounting Policies | BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation and Principles of Consolidation The consolidated financial statements and accompanying notes (the “Financial Statements”) have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”) and with the rules and regulations of the Securities and Exchange Commission (“SEC”), specifically Regulation S-X and the instructions to Form 10-K. Unless otherwise indicated, all references to years are to our fiscal year, which ends on October 31 . The Financial Statements include the accounts of ABM and all of our consolidated subsidiaries. We account for ABM’s investments in unconsolidated affiliates under the equity method of accounting. We include the results of acquired businesses in the consolidated statements of comprehensive income from their respective acquisition dates. All intercompany accounts and transactions have been eliminated in consolidation. The preparation of consolidated financial statements in accordance with U.S. GAAP requires our management to make certain estimates that affect the reported amounts. We base our estimates on historical experience, known or expected trends, independent valuations, and various other assumptions that we believe to be reasonable under the circumstances. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. We round amounts in the Financial Statements to millions and calculate all percentages and per-share data from the underlying whole-dollar amounts. Thus, certain amounts may not foot, crossfoot, or recalculate based on reported numbers due to rounding. Acquisition of GCA Services Group On September 1, 2017 (the “Acquisition Date”), we completed the acquisition of GCA Services Group (“GCA”). Accordingly, our consolidated statements of comprehensive income and statements of cash flows include GCA’s results of operations in 2019 and 2018, but exclude GCA’s results of operations in 2017 prior to the Acquisition Date. See Note 4 , “Acquisitions,” for further information on the acquisition of GCA. Government Services At October 31, 2016, the assets and liabilities of our former Government Services business were classified as held for sale, at which time we wrote down goodwill and long-lived assets of this business by $22.5 million to reflect our best estimate of fair value less costs to sell, using all information available at that time. During the second quarter of 2017, we received an offer from a strategic buyer to purchase this business for approximately $35.0 million , which was higher than our previous estimate of fair value less costs to sell. As a result, we recorded a $17.4 million impairment recovery to adjust the fair value of certain previously impaired assets to the valuation of the assets as implied by the agreed-upon sales price, less estimated costs to sell. We sold this business on May 31, 2017 for $35.5 million and recorded a pre-tax gain of $1.2 million . The impairment charges, subsequent recovery, and gain on sale are reflected in impairment loss (recovery) in the accompanying consolidated statements of comprehensive income. The reported results for this business are through the date of sale and future results could include run-off costs. Prior Year Reclassifications Effective November 1, 2018, we have modified the presentation of inter-segment revenues, which are recorded at cost with no associated intercompany profit or loss and are eliminated in consolidation. Additionally, during the third quarter of 2019, we made changes to our operating structure to better align the services and expertise of our Healthcare business with our other industry groups, allowing us to leverage our existing branch network to support the long-term growth of this business. As a result, our former Healthcare portfolio is now included primarily in our Business & Industry segment. Our prior period segment data in Note 19 , “Segment and Geographic Information,” has been reclassified to conform with our current period presentation. These changes had no impact on our previously reported consolidated financial statements. Cash and Cash Equivalents We consider all highly liquid securities with an original maturity of three months or less to be cash and cash equivalents. As part of our cash management system, we use “zero balance” accounts to fund our disbursements. Under this system, at the end of each day the bank balance is zero, while the book balance is usually a negative amount due to reconciling items, such as outstanding checks. We report the changes in these book cash overdrafts as cash flows from financing activities. Trade Accounts Receivable and Costs Incurred in Excess of Amounts Billed Trade accounts receivable arise from services provided to our clients and are usually due and payable on varying terms from receipt of the invoice to net ninety days, with the exception of certain Technical Solutions project receivables that may have longer collection periods. These receivables are recorded at the invoiced amount and normally do not bear interest. In addition, our trade accounts receivable include unbilled receivables, such as invoices for services that have been provided but are not yet billed. Costs incurred in excess of amounts billed arise from Technical Solutions project contracts that typically provide for a schedule of billings or invoices to the client based on our performance to date of specific tasks inherent in the fulfillment of our performance obligation(s). The schedules for such billings usually do not precisely match the schedule on which costs are incurred. As a result, revenues generally differ from amounts that can billed or invoices to the client at any point during the contract. Allowance for Doubtful Accounts We determine the allowance for doubtful accounts based on historical write-offs, known or expected trends, and the identification of specific balances deemed uncollectible. For the specifically identified balances, we establish the reserve upon the earlier of a client’s inability to meet its financial obligations or after a period of twelve months, unless our management believes such amounts will ultimately be collectible. Sales Allowance In connection with our service contracts, we periodically issue credit memos to our clients that are recorded as a reduction in revenues and an increase to the allowance for billing adjustments. These credits can result from client vacancy discounts, job cancellations, property damage, and other items. We estimate our potential future losses on these client receivables based on an analysis of the historical rate of sales adjustments (credit memos, net of re-bills) and known or expected trends. Other Current Assets At October 31, 2019 and 2018 , other current assets primarily consisted of other receivables, short-term insurance recoverables, and capitalized commissions. Other Investments At October 31, 2019 and 2018 , other investments primarily consisted of investments in unconsolidated affiliates and in auction rate securities. Investments in Unconsolidated Affiliates We own non-controlling interests (generally 20% to 50% ) in certain affiliated entities that predominantly provide facility solutions to governmental and commercial clients, primarily in the United States and the Middle East. We account for such investments under the equity method of accounting. We evaluate our equity method investments for impairment whenever events or changes in circumstances indicate that the carrying amounts of such investments may not be recoverable. An impairment loss is recognized to the extent that the estimated fair value of the investment is less than its carrying amount and we determine that the impairment is other-than-temporary. At October 31, 2019 , 2018 , and 2017 , our investments in unconsolidated affiliates were $8.9 million , $11.3 million , and $9.3 million , respectively. We did not recognize any impairment charges on these investments in 2019, 2018, or 2017. Investments in Auction Rate Securities Our investments in auction rate securities are classified as available-for-sale. Accordingly, auction rate securities are presented at fair value with unrealized gains and losses recorded in accumulated other comprehensive income (loss), net of taxes (“AOCI”). On a quarterly basis, we analyze all auction rate securities that have unrealized losses for impairment consideration and assess the intent to sell such securities. If such intent exists, impaired securities are considered other-than-temporarily impaired and we recognize the entire difference between the auction rate security’s amortized cost and its fair value in earnings. We also consider if we may be required to sell the securities prior to the recovery of amortized cost, which may trigger an impairment charge. If these securities are considered impaired, we assess whether the amortized costs of the securities can be recovered by reviewing several factors, including credit risks associated with the issuer. If we do not expect to recover the entire amortized cost of the security, we consider the security to be other-than-temporarily impaired, and record the difference between the security’s amortized costs and its recoverable amount in earnings and the difference between the security’s amortized cost and fair value in AOCI. Property, Plant and Equipment We record property, plant and equipment at cost. Repairs and maintenance expenditures are expensed as incurred. In contrast, we capitalize major renewals or replacements that substantially extend the useful life of an asset. We determine depreciation for financial reporting purposes using the straight-line method over the following estimated useful lives: Category Years Computer equipment and software 3–5 Machinery and other equipment 3–5 Transportation equipment 1.5–10 Buildings 10–40 Furniture and fixtures 5 In addition, we depreciate assets under capital leases and leasehold improvements over the shorter of their estimated useful lives or the remaining lease term. Upon retirement or sale of an asset, we remove the cost and accumulated depreciation from our consolidated balance sheets. When applicable, we record corresponding gains or losses within the accompanying consolidated statements of comprehensive income. Leases We enter into various noncancelable lease agreements for premises and equipment used in the normal course of business. We evaluate the lease agreement at the inception of the lease to determine whether the lease is an operating lease or capital lease. We account for rent expense under noncancelable operating leases with escalation clauses on a straight-line basis over the initial lease term. A deferred liability is recorded for the amount of the excess of straight-line rent expense over scheduled payments. We do not assume renewals in our determination of the lease term unless the renewals are deemed to be reasonably assured at lease inception. We may also be required to make additional payments to reimburse the lessors for operating expenses such as real estate taxes, maintenance, utilities, and insurance, which are expensed as incurred. We enter into leases of parking lots and garages that contain contingent payment provisions. Under these provisions, we pay contingent amounts in addition to base rent, primarily based on percentages of the gross receipts or other financial parameters attributable to the related facilities. We record contingent rent as it becomes probable that specified targets will be met. We record each capital lease as an asset and an obligation at an amount that is equal to the present value of the minimum lease payments over the lease term. Goodwill and Other Intangible Assets Goodwill represents the excess purchase price of acquired businesses over the fair value of the assets acquired and liabilities assumed. We have elected to make the first day of our fourth quarter, August 1st, the annual impairment assessment date for goodwill. However, we could be required to evaluate the recoverability of goodwill more often if impairment indicators exist. Goodwill is tested for impairment at a “reporting unit” level by performing either a qualitative evaluation or a quantitative test. The qualitative evaluation is an assessment of factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. We may elect not to perform the qualitative assessment for some or all reporting units and perform a quantitative test instead, under which fair value is determined based on discounted cash flow analyses. The discounted estimates of future cash flows include significant management assumptions, such as revenue growth rates, operating margins, weighted average cost of capital, and future economic and market conditions. In 2017, we adopted Accounting Standards Update (“ASU”) 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment , which allows us to test goodwill for impairment by comparing the fair value of a reporting unit to its carrying amount. If the fair value of a reporting unit is less than its carrying value, an impairment charge will be recorded for the difference between the fair value and carrying value, but it is limited to the carrying value of the reporting unit’s goodwill. Other intangible assets primarily consist of acquired customer contracts and relationships that are amortized using the sum-of-the-years-digits method over their useful lives, consistent with the estimated useful life considerations used in the determination of their fair values. This accelerated method of amortization reflects the pattern in which the economic benefits from the intangible assets of customer contracts and relationships are expected to be realized. We amortize other non-customer acquired intangibles using a straight-line method of amortization. We evaluate other intangible assets, as well as our long-lived assets, for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. When this occurs, a recoverability test is performed that compares the projected undiscounted cash flows from the use and eventual disposition of an asset or asset group to its carrying amount. If the projected undiscounted cash flows are less than the carrying amount, we calculate an impairment loss. The impairment loss calculation compares the fair value, which is based on projected discounted cash flows, to the carrying value. See Note 11 , “Goodwill and Other Intangible Assets,” for further information on goodwill, other intangible assets, and impairment charges. Other Noncurrent Assets At October 31, 2019 and 2018 , other noncurrent assets primarily consisted of long-term insurance recoverables, deferred charges, insurance and other long-term deposits, federal energy savings performance contract receivables, capitalized commissions, and prepayments to carriers for future insurance claims. Federal Energy Savings Performance Contract Receivables As part of our Technical Solutions business, we enter into energy savings performance contracts (“ESPCs”) with the federal government pursuant to which we agree to develop, design, engineer, and construct a project and to guarantee that the project will satisfy agreed-upon performance standards. ESPC receivables represent the amount to be paid by various federal government agencies for work we have satisfactorily performed under specific ESPCs. We assign certain of our rights to receive those payments to unaffiliated third parties that provide construction financing, which we record as a liability, for such contracts. This construction financing is recorded as cash flows from financing activities, while the use of the cash received to pay project costs under these arrangements is classified as operating cash flows. The ESPC receivable is recognized as revenue as each project is constructed. Upon completion and acceptance of the project by the government and upon satisfaction of true sale criteria, the assigned ESPC receivable from the government and corresponding ESPC liability are eliminated from our consolidated financial statements. Fair Value of Financial Instruments Fair value is the price we would receive to sell an asset or pay to transfer a liability in an orderly transaction with a market participant at the measurement date. In the absence of active markets for the identical assets or liabilities, such measurements involve developing assumptions based on market observable data and, in the absence of such data, internal information that is consistent with what market participants would use in a hypothetical transaction that occurs at the measurement date. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect our market assumptions. Preference is given to observable inputs. These two types of inputs create the following fair value hierarchy: Level 1 – Quoted prices for identical instruments in active markets; Level 2 – Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations whose inputs are observable or whose significant value drivers are observable; and Level 3 – Significant inputs to the valuation model are unobservable. We evaluate assets and liabilities subject to fair value measurements on a recurring and non-recurring basis to determine the appropriate level at which to classify them for each reporting period. Some non-financial assets are measured at fair value on a non-recurring basis only in certain circumstances, including the event of impairment. See Note 8 , “Fair Value of Financial Instruments,” for the fair value hierarchy table and for details on how we measure fair value for our assets and liabilities. Acquisitions We expense acquisition-related costs as incurred. On the date of the acquisition, we allocate the purchase price to the assets acquired and liabilities assumed at their estimated fair values. Goodwill on the acquisition date is measured as the excess of the purchase price over the fair values of assets acquired and liabilities assumed. While we use our best estimates and assumptions to accurately value assets acquired and liabilities assumed at the acquisition date as well as contingent consideration, where applicable, our estimates are subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, we record adjustments to the assets acquired and liabilities assumed with corresponding adjustments to goodwill. We recognize subsequent changes in the estimate of the amount to be paid under contingent consideration arrangements in the accompanying consolidated statements of comprehensive income. Discontinued Operations In order to be reported within discontinued operations, our disposal of a component or a group of components must represent a strategic shift that will have a major effect on our operations and financial results. We aggregate the results of operations for discontinued operations within a single line item on the income statement. General corporate overhead is not allocated to discontinued operations. We disclose any gain or loss that is recognized upon the disposition of a discontinued operation. Prior to disposition, we aggregate the assets and liabilities of discontinued operations and report the amounts on separate line items within the balance sheet. Assets and Liabilities Held for Sale Upon a business being classified as held for sale, we cease all depreciation and amortization related to the assets of the business and record them at the lower of their carrying amount or fair value less estimated costs to sell. The assets and related liabilities of the business are separately presented on the consolidated balance sheets. We review all assets held for sale each reporting period to determine whether the existing carrying amounts are fully recoverable in comparison to estimated fair values. Insurance Reserves We use a combination of insured and self-insurance programs to cover workers’ compensation, general liability, automobile liability, property damage, and other insurable risks. Insurance claim liabilities represent our estimate of retained risks without regard to insurance coverage. We retain a substantial portion of the risk related to certain workers’ compensation and medical claims. Liabilities associated with these losses include estimates of both filed claims and incurred but not reported claims (“IBNR Claims”). With the assistance of third-party actuaries, we periodically review our estimate of ultimate losses for IBNR Claims and adjust our required self-insurance reserves as appropriate. As part of this evaluation, we review the status of existing and new claim reserves as established by third-party claims administrators. The third-party claims administrators establish the case reserves based upon known factors related to the type and severity of the claims, demographic factors, legislative matters, and case law, as appropriate. We compare actual trends to expected trends and monitor claims developments. The specific case reserves estimated by the third-party administrators are provided to an actuary who assists us in projecting an actuarial estimate of the overall ultimate losses for our self-insured or high deductible programs, which includes the case reserves plus an actuarial estimate of reserves required for additional developments, such as IBNR Claims. We utilize the results of actuarial studies to estimate our insurance rates and insurance reserves for future periods and to adjust reserves, if appropriate, for prior years. In general, our insurance reserves are recorded on an undiscounted basis. We allocate current-year insurance expense to our operating segments based upon their underlying exposures, while actuarial adjustments related to prior year claims are recorded within Corporate expenses. We classify claims as current or long-term based on the expected settlement date. Estimated insurance recoveries related to recorded liabilities are reflected as assets in our consolidated balance sheets when we believe that the receipt of such amounts is probable. Other Accrued Liabilities At October 31, 2019 and 2018 , other accrued liabilities primarily consisted of employee benefits, contract liabilities (which include deferred revenue and progress billings in excess of costs), legal fees and settlements, dividends payable, current capital leases, interest, insurance claims, severance, rent payable, and other accrued expenses. Other Noncurrent Liabilities At October 31, 2019 and 2018 , other noncurrent liabilities primarily consisted of ESPC liabilities, deferred rent, retirement plan liabilities, deferred compensation, and long-term capital leases. Other noncurrent liabilities at October 31, 2019 also includes our interest rate swaps. Revenue Recognition Beginning in fiscal 2019, we adopted ASU 2014-09, Revenue from Contracts with Customers (Topic 606) , and ASU 2017-10 , Service Concession Arrangements (Topic 853): Determining the Customer of the Operation Services . Prior period amounts have not been restated and continue to be reported in accordance with our historical accounting policies. Our revenue recognition policies under Topic 606 and Topic 853 are described in the following paragraphs and references to prior period policies are included below where they are substantially different. See Note 3 , “Revenues,” for further information on our revenues, including the impact of adopting Topic 606 and Topic 853 on our consolidated financial statements. Contracts with Customers We account for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance, and collectability of consideration is probable. Once a contract is identified, we evaluate whether it is a combined or single contract and whether it should be accounted for as more than one performance obligation. Generally, most of our contracts are cancelable by either party without a substantive penalty, and the majority of our contracts have a notification period of 30 to 60 days. If a contract includes a cancellation clause, the remaining contract term is limited to the required termination notice period. At contract inception, we assess the services promised to our customers and identify a performance obligation for each promise to transfer to the customer a service, or a bundle of services, that is distinct. To identify the performance obligation, we consider all of our services promised in the contract, regardless of whether they are explicitly stated or are implied by customary business practices. The majority of our contracts contain multiple promises that represent an integrated bundle of services comprised of activities that may vary over time; however, these activities fulfill a single integrated performance obligation since we perform a continuous service that is substantially the same and has the same pattern of transfer to the customer. Our performance obligations are primarily satisfied over time as we provide the related services. We allocate the contract transaction price to this single performance obligation and recognize revenue as the services are performed, as further described in “Contract Types” below. Certain arrangements involve variable consideration (primarily per transaction fees, reimbursable expenses, and sales-based royalties). We do not estimate the variable consideration for these arrangements; rather, we recognize these variable fees in the period they are earned. Some of our contracts, often related to Airline Services, may also include performance incentives based on variable performance measures that are ascertained exclusively by future performance and therefore cannot be estimated at contract inception and are recognized as revenue once known and mutually agreed upon. We include estimated amounts in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. Our estimates of variable consideration and determination of whether to include estimated amounts in the transaction price are based largely on an assessment of our anticipated performance and all information (historical, current, and forecasted) that is reasonably available to us. We primarily account for our performance obligations under the series guidance, using the as-invoiced practical expedient when applicable. We apply the as-invoiced practical expedient to record revenue as the services are provided, given the nature of the services provided and the frequency of billing under the customer contracts. Under this practical expedient, we recognize revenue in an amount that corresponds directly with the value to the customer of our performance completed to date and for which we have the right to invoice the customer. We typically bill customers on a monthly basis and have the right to consideration from customers in an amount that corresponds directly with the performance obligation satisfied to date. The time between completion of the performance obligation and collection of cash is generally 30 to 60 days. Sales-based taxes are excluded from revenue. Contracts generally can be modified to account for changes in specifications and requirements. We consider contract modifications to exist when the modification either changes the consideration, creates new performance obligations, or changes the existing scope of the contract and related performance obligations. Historically, contract modifications have been for services that are not distinct from the existing contract, since we are providing a bundle of services that are highly inter-related, and are therefore treated as if they were part of that existing contract. Such modifications are generally accounted for prospectively as part of the existing contract. Contract Types We have arrangements under various contract types, as described below. Monthly Fixed-Price Monthly fixed-price arrangements are contracts in which the client agrees to pay a fixed fee every month over a specified contract term. We measure progress toward satisfaction of the performance obligation as the services are provided, and revenue is recognized at the agreed-upon contractual amount over time because the customer simultaneously receives and consumes the benefits of the services as they are performed. Square-Foot Monthly square-foot arrangements are contracts in which the client agrees to pay a fixed fee every month based on the actual square footage serviced over a specified contract term. We measure progress toward satisfaction of the performance obligation as the services are provided, and revenue is recognized at the agreed-upon contractual amount over time because the customer simultaneously receives and consumes the benefits of the services as they are performed. Cost-Plus Cost-plus arrangements are contracts in which the clients reimburse us for the agreed-upon amount of wages and benefits, payroll taxes, insurance charges, and other expenses associated with the contracted work, plus a profit margin. We measure progress toward satisfaction of the performance obligation as the services are provided, and revenue is recognized at the agreed-upon contractual amount over time because the customer simultaneously receives and consumes the benefits of the services as they are performed. Tag Services Tag services (work orders) generally consist of supplemental services requested by clients outside of the standard service specification and include cleanup after tenant moves, construction cleanup, flood cleanup, and snow removal. Because the nature of these short-term contracts involves performing one-off type services, revenue is recognized at the agreed-upon contractual amount over time as the services are provided, because the customer simultaneously receives and consumes the benefits of the services as they are performed. Transaction-Price Transaction-price contracts are arrangements in which customers are billed a fixed price for each transaction performed on a monthly basis (e.g., wheelchair passengers served, airplane cabins cleaned). We measure progress toward satisfaction of the performance obligation as the services are provided, and revenue is recognized at the agreed-upon contractual amount over time because the customer simultaneously receives and consumes the benefits of the services as they are performed. Hourly Hourly arrangements are contracts in which the client is billed a fixed hourly rate for each labor hour provided. We measure progress toward satisfaction of the performance obligation as the services are provided, and revenue is recognized at the agreed-upon contractual amount over time because the customer simultaneously receives and consumes the benefits of the services as they are performed. Management Reimbursement Under management reimbursement arrangements we manage a parking facility for a management fee and pass through the revenue and expenses associated with the facility to the owner. We measure progress toward satisfaction of the performance obligation over time as the services are provided. Under these contracts we recognize both revenues and expenses, in equal amounts, that are directly reimbursed from the property owner for operating expenses, as such expenses are incurred. Such revenues do not include gross customer collections at the managed locations because they belong to the property owners. We have determined we are the principal in these transactions, because the nature of our performance obligation is for us to provide the services on behalf of the customer and we have control of the promised services before they are transferred to the customer. Leased Location Under leased location parking arrangements we pay a fixed amount of rent, plus a percentage of revenues derived from monthly and transient parkers, to the property owner. We retain all revenues received and we are responsible for most operating expenses incurred. We measure progress toward satisfaction of the performance obligation as the services are provided, and revenue is recognized over time because the customer simultaneously receives and consumes the benefits of the services as they are performed. In accord |