Insurance [Abstract] Schedule of Insurance Related Balances and Activity Schedule Of Insurance Related Balances And Activity [Table Text Block] Schedule Of Insurance Related Balances And Activity [Table Text Block] Schedule of Instruments Used to Collateralize Insurance Obligations Insurance Disclosure [Table Text Block] Insurance Disclosure Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Restructuring and Related Activities [Abstract] Restructuring and Related Costs Restructuring and Related Activities Disclosure [Text Block] Debt Disclosure [Abstract] Current portion of long-term debt Long-term Debt, Current Maturities [Abstract] Gross term loan Loans Payable, Current, Gross Loans Payable, Current, Gross Less: unamortized deferred financing costs Debt Issuance Costs, Current, Net Current portion of term loan Long-term Debt, Current Maturities Long-term debt Long-term Debt, Excluding Current Maturities [Abstract] Gross term loan Loans Payable, Noncurrent, Gross Loans Payable, Noncurrent, Gross Less: unamortized deferred financing costs Debt Issuance Costs, Noncurrent, Net Total noncurrent portion of term loan Loans Payable, Noncurrent Line of credit Long-term Line of Credit, Noncurrent Long-term debt Long-term Debt, Excluding Current Maturities Standby letters of credit Letters of Credit Outstanding, Amount Borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Borrowing capacity after covenant restrictions Line of Credit Facility, Remaining Borrowing Capacity After Covenant Restrictions Line of Credit Facility, Remaining Borrowing Capacity After Covenant Restrictions Earnings Per Share [Abstract] Schedule Of Earnings Per Share Basic And Diluted By Common Class [Table] Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Table] Schedule of Share-based Compensation Arrangement by Share-based Payment Award Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Restricted stock units Restricted Stock Units (RSUs) [Member] Stock options Employee Stock Option [Member] Performance shares Performance Shares [Member] Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items] Schedule Of Earnings Per Share Basic And Diluted By Common Class [Line Items] Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items] Income from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Income (loss) from discontinued operations, net of taxes Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Net income (loss) Net Income (Loss) Attributable to Parent Weighted-average common and common equivalent shares outstanding - Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Effect of dilutive securities Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Effect of dilutive securities (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Weighted-average common and common equivalent shares outstanding - Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Net income (loss) per common share — Basic Earnings Per Share, Basic [Abstract] Income from continuing operations (in usd per share) Income (Loss) from Continuing Operations, Per Basic Share Loss from discontinued operations (in usd per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Net income (loss) (in usd per share) Earnings Per Share, Basic Net income (loss) per common share — Diluted Earnings Per Share, Diluted [Abstract] Income from continuing operations (in usd per share) Income (Loss) from Continuing Operations, Per Diluted Share Loss from discontinued operations (in usd per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Net income (loss) (in usd per share) Earnings Per Share, Diluted Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Employee Severance Employee Severance [Member] External Support Fees External Support Fees [Member] External Support Fees [Member] Lease Exit Lease Exit [Member] Lease Exit [Member] Other Project Fees Other Project Fees [Member] Other Project Fees [Member] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Restructuring Reserve [Roll Forward] Restructuring Reserve [Roll Forward] Balance, beginning of period Restructuring Reserve Costs recognized Restructuring Charges Payments Payments for Restructuring Non-cash charges Restructuring Reserve, Accrual Adjustment Balance, end of period Income Tax Disclosure [Abstract] Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Forecast Scenario, Forecast [Member] Income Taxes [Line Items] Operating Loss Carryforwards [Line Items] U.S. statutory federal rate (percent) Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Net discrete tax benefit from remeasurement of deferred taxes at new rate due to Tax Act Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Expense (Benefit) Amount of reasonable estimate for income tax expense (benefit) for remeasurement of deferred tax from change in tax rate pursuant to Tax Cuts and Jobs Act of 2017 for which accounting for tax effect is incomplete. One-time transition tax on deemed repatriation of indefinitely reinvested earnings Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Transition Tax for Accumulated Foreign Earnings, Provisional Income Tax Expense Amount of reasonable estimate for income tax expense from transition tax on accumulated earnings of controlled foreign corporation deemed repatriated pursuant to Tax Cuts and Jobs Act of 2017 for which accounting for tax effect is incomplete. Tax deductions for energy efficient government buildings Effective Income Tax Reconciliation, Deduction Energy Efficient Government Buildings, Amount Effective Income Tax Reconciliation, Deduction Energy Efficient Government Buildings, Amount Increase (decrease) in tax credits, work opportunity tax credit Increase (Decrease) in Tax Credits, Work Opportunity Tax Credit Increase (Decrease) in Tax Credits, Work Opportunity Tax Credit Discrete tax benefit related to enactment of Tax Act Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional Income Tax Expense (Benefit) Amount of reasonable estimate for income tax expense (benefit) from effect of Tax Cuts and Jobs Act of 2017 for which accounting for tax effect is incomplete. Income tax benefit related to vesting of share-based compensation awards Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Business Combinations [Abstract] Schedule of Consideration Transferred Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable [Table Text Block] Schedule of Preliminary Purchase Price Allocation Schedule of Business Acquisitions, by Acquisition [Table Text Block] Schedule of Pro Forma Financial Information Business Acquisition, Pro Forma Information [Table Text Block] Accounting Policies [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Business & Industry Business and Industry [Member] Business and Industry [Member] Aviation Aviation [Member] Aviation [Member] Healthcare Healthcare [Member] Healthcare [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Parking facility management fee revenue Reimbursement Revenue Statement of Financial Position [Abstract] Trade accounts receivable, allowance Allowance for Doubtful Accounts Receivable, Current Property, plant and equipment, accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Other intangible assets, accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Preferred stock, par value (in usd per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Common stock, par value (in usd per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares issued (in shares) Common Stock, Shares, Issued Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Management Reimbursement Revenue by Segment Revenue Recognition, Policy [Policy Text Block] New accounting pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Schedule of Credit Facility Information Schedule of Long-term Debt Instruments [Table Text Block] Schedule of Term Loan Maturities Schedule of Maturities of Long-term Debt [Table Text Block] Schedule of Interest Rate Swap Information Schedule of Interest Rate Derivatives [Table Text Block] Net Income Per Common Share Earnings Per Share [Text Block] Schedule of Management Reimbursement Revenue by Segment Management Revenue [Table Text Block] Management Revenue [Table Text Block] Loss Contingencies [Table] Loss Contingencies [Table] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Hussein And Isse Hussein And Isse [Member] Hussein And Isse [Member] Isse Isse [Member] Isse [Member] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Energy Savings Contracts Energy Savings Contracts [Member] Energy Savings Contracts [Member] Performance Guarantee Performance Guarantee [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Joint Venture Corporate Joint Venture [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Surety bonds Surety Bonds The amount of bonds, as of the end of the accounting period, issued by a second party, guaranteeing the fulfillment of the Company's obligations to a third party. In the event that the Company does not meet its obligations, the third party will recover its losses via the bond. Guarantee obligation Guarantee Obligation The total amount of guaranteed energy savings. Subsidiary ownership interest (in percent) Equity Method Investment, Ownership Percentage Total guarantees Guarantor Obligations, Maximum Exposure, Undiscounted Loss contingency amount accrued for probable losses Loss Contingency Accrual Litigation losses Litigation Settlement, Expense Amount of reasonably possible loss Loss Contingency, Estimate of Possible Loss Number of plaintiffs Loss Contingency, Number of Plaintiffs Settlement amount Litigation Settlement, Amount Awarded to Other Party Payments for legal settlements Payments for Legal Settlements Fair Value Disclosures [Abstract] Schedule of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis Fair Value, by Balance Sheet Grouping [Table Text Block] Fair Value of Financial Instruments Fair Value Disclosures [Text Block] Schedule of Basic and Diluted Net Income Per Common Share Calculations Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Anti-Dilutive Outstanding Stock Awards Issued Under Share-Based Compensation Plans Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 1 Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 Fair Value, Inputs, Level 3 [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Insurance deposits Restricted Cash and Cash Equivalents, Noncurrent Assets held in funded deferred compensation plan Deferred Compensation Plan Assets Credit facility Debt Instrument, Fair Value Disclosure Interest rate swaps Interest Rate Derivative Assets, at Fair Value Investments in auction rate securities Available-for-sale Securities Contingent consideration liability Business Combination, Contingent Consideration, Liability Asset Impairment Asset Impairment [Member] Asset Impairment [Member] Restructuring Plan [Axis] Restructuring Plan [Axis] Restructuring Plan [Domain] Restructuring Plan [Domain] GCA Restructuring Program GCA Restructuring Program [Member] GCA Restructuring Program [Member] 2020 Vision Restructuring Program 2020 Vision Restructuring Program [Member] 2020 Vision Restructuring Program [Member] Cumulative charges Restructuring and Related Cost, Cost Incurred to Date Segment Reporting [Abstract] Segment Information Segment Reporting Disclosure [Text Block] Investments, Debt and Equity Securities [Abstract] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Discount rates Securities Discount Rate Over London Interbank Offered Rate The discount rate over London Interbank Offered Rate assumptions used to determine the fair value of auction rate securities. Libor plus stated yield Securities Yields Over London Interbank Offered Rate The fixed yield over London Interbank Offered Rate used as an input in determining the fair value for the one of the Company's auction rate securities. Yields Securities Yields The fixed yield used as an input in determining the fair value for one of the Company's auction rate securities. Average expected lives Average Expected Life, Auction Rate Securities The average expected life assumptions used to determine the fair value of auction rate securities. Auction Rate Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] ASSETS Assets [Abstract] Current assets Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Trade accounts receivable, net of allowances of $16.4 and $25.5 at April 30, 2018 and October 31, 2017, respectively Accounts Receivable, Net, Current Prepaid expenses Prepaid Expense, Current Other current assets Other Assets, Current Total current assets Assets, Current Other investments Other Long-term Investments Property, plant and equipment, net of accumulated depreciation of $156.2 and $136.4 at April 30, 2018 and October 31, 2017, respectively Property, Plant and Equipment, Net Other intangible assets, net of accumulated amortization of $222.4 and $189.1 at April 30, 2018 and October 31, 2017, respectively Finite-Lived Intangible Assets, Net Goodwill Goodwill Other noncurrent assets Other Assets, Noncurrent Total assets Assets LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities and Equity [Abstract] Current liabilities Liabilities, Current [Abstract] Current portion of long-term debt, net Trade accounts payable Accounts Payable, Current Accrued compensation Employee-related Liabilities, Current Accrued taxes—other than income Accrual for Taxes Other than Income Taxes, Current Insurance claims Self Insurance Reserve, Current Income taxes payable Accrued Income Taxes, Current Other accrued liabilities Other Accrued Liabilities, Current Total current liabilities Liabilities, Current Long-term debt, net Deferred income tax liability, net Deferred Income Tax Liabilities, Net Noncurrent insurance claims Self Insurance Reserve, Noncurrent Other noncurrent liabilities Other Liabilities, Noncurrent Noncurrent income taxes payable Accrued Income Taxes, Noncurrent Total liabilities Liabilities Commitments and contingencies Commitments and Contingencies Stockholders’ Equity Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, $0.01 par value; 500,000 shares authorized; none issued Preferred Stock, Value, Issued Common stock, $0.01 par value; 100,000,000 shares authorized; 65,729,949 and 65,502,568 shares issued and outstanding at April 30, 2018 and October 31, 2017, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Accumulated other comprehensive income (loss), net of taxes Accumulated Other Comprehensive Income (Loss), Net of Tax Retained earnings Retained Earnings (Accumulated Deficit) Total stockholders’ equity Stockholders' Equity Attributable to Parent Total liabilities and stockholders’ equity Liabilities and Equity Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Mechanical Solutions Inc (MSI) Mechanical Solutions Inc [Member] Mechanical Solutions Inc [Member] OFJ Connections Ltd (OFJ) OFJ Connections Ltd [Member] OFJ Connections Ltd [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Purchase price Business Combination, Consideration Transferred Schedule of Financial Information by Reportable Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] The Company and Nature of Operations Nature of Operations [Text Block] Insurance Insurance Disclosure [Text Block] Schedule of Restructuring and Related Liabilities Restructuring and Related Costs [Table Text Block] Business Acquisition, Pro Forma Information, Nonrecurring Adjustments [Table] Business Acquisition, Pro Forma Information, Nonrecurring Adjustments [Table] GCA Holding Corp. GCA Holding Corp. [Member] GCA Holding Corp. [Member] Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items] Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items] Revenue related to GCA recorded in reporting period Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual Operating profit related to GCA recorded in reporting period Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual Pro forma statutory tax rate (percent) Business Acquisition, Pro Forma Statutory Tax Rate Business Acquisition, Pro Forma Statutory Tax Rate Pro forma revenue Business Acquisition, Pro Forma Revenue Pro forma income from continuing operations Business Acquisition, Pro Forma Income (Loss) from Continuing Operations, Net of Tax Number of industry groups Number Of Industry Groups Number Of Industry Groups Number of technical solutions segments Number Of Technical Solution Segments Number Of Technical Solution Segments Anti-dilutive (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Term Loan Loans Payable [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Debt instrument, periodic payment, principal Debt Instrument, Periodic Payment, Principal Term Loan Maturities Maturities of Long-term Debt [Abstract] Debt maturities, 2019 Long-term Debt, Maturities, Repayments of Principal in Year Two Debt maturities, 2020 Long-term Debt, Maturities, Repayments of Principal in Year Three Debt maturities, 2021 Long-term Debt, Maturities, Repayments of Principal in Year Four Debt maturities, 2022 Long-term Debt, Maturities, Repayments of Principal in Year Five Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Customer relationships Customer Relationships [Member] Trade names Trade Names [Member] Cash and cash equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Adjustment, Cash and cash equivalents Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Cash And Cash Equivalents Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Cash And Cash Equivalents Trade accounts receivable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables Prepaid expenses and other current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets Property, plant and equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Adjustment, Property, plant and equipment Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment Intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Adjustment, Intangible assets Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles Adjustment, Goodwill Goodwill, Purchase Accounting Adjustments Other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Adjustment, Other assets Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Other Assets Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Other Assets Trade accounts payable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable Adjustment, Trade accounts payable Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Trade Accounts Payable Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Trade Accounts Payable Insurance reserves Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Insurance Reserves Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Insurance Reserves Adjustment, Insurance reserves Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Insurance Reserves Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Insurance Reserves Income taxes payable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Income Taxes Payable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Income Taxes Payable Adjustment, Income taxes payable Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Income Taxes Payable Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Income Taxes Payable Accrued liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other Adjustment, Accrued liabilities Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Accrued Liabilities Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Accrued Liabilities Deferred income tax liability, net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Adjustment, Deferred income tax liability, net Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Deferred Income Tax Liabilities Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Deferred Income Tax Liabilities Other liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Net assets acquired Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Adjustment, Net assets acquired Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred Acquired Receivables Business Combination, Acquired Receivables [Abstract] Trade accounts receivable, gross Business Combination, Acquired Receivables, Gross Contractual Amount Estimated uncollectible trade accounts receivable Business Combination, Acquired Receivables, Estimated Uncollectible Acquired Intangible Assets Finite-Lived Intangible Assets, Gross [Abstract] Amortization period for acquired intangible assets Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Liability for Claims and Claims Adjustment Expense [Table] Liability for Claims and Claims Adjustment Expense [Table] Insurance Policies [Axis] Insurance Policies [Axis] Insurance Policies [Axis] Insurance Policies [Domain] Insurance Policies [Domain] Insurance Policies [Domain] Claim Types Excluding Medical and Dental All Other Claim Types [Member] All Other Claim Types [Member] Medical and Dental Claims Medical And Dental Self Insurance Program [Member] Medical and Dental Self Insurance Program [Member] Liability for Claims and Claims Adjustment Expense [Line Items] Liability for Claims and Claims Adjustment Expense [Line Items] Insurance claim reserves Self Insurance Reserve Insurance recoverables Estimated Insurance Recoveries Income Statement [Abstract] Revenues Sales Revenue, Services, Net Operating expenses Cost of Services Selling, general and administrative expenses Selling, General and Administrative Expense Restructuring and related expenses Amortization of intangible assets Amortization of Intangible Assets Impairment recovery Disposal Group, Not Discontinued Operation, Gain (Loss) On Disposal And Reversal Or Write Down Disposal Group, Not Discontinued Operation, Gain (Loss) On Disposal And Reversal Or Write Down Operating profit Operating Income (Loss) Income from unconsolidated affiliates, net Income (Loss) from Equity Method Investments Interest expense Interest Expense Income from continuing operations before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax (provision) benefit Income Tax Expense (Benefit) Income from continuing operations Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax [Abstract] Change in fair value of interest rate swaps Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Foreign currency translation Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent Income tax provision Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Weighted-average common and common equivalent shares outstanding Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic (in shares) Diluted (in shares) Dividends declared per common share (in usd per share) Common Stock, Dividends, Per Share, Declared Credit Facility Debt And Derivative Instruments Disclosure [Text Block] The entire disclosure for the entity's debt and derivative instruments. Includes information about the amount of borrowings under the entity's line of credit and other matters important to the users of the financial statements and describes an entity's risk management strategies, derivatives in hedging activities and non-hedging derivative instruments, the assets, obligations, liabilities, revenues and expenses arising there from, and the amounts of and methodologies and assumptions used in determining the amounts of such items. Line of Credit Facility [Table] Line of Credit Facility [Table] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Prior Credit Facility Prior Credit Facility [Member] Prior Credit Facility [Member] Credit Facility Credit Facility [Member] Credit Facility [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Eurodollar Eurodollar [Member] Base Rate Base Rate [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Standby Letters of Credit Standby Letters of Credit [Member] Swing Line Loan Swing Line Loan [Member] Swing Line Loan [Member] Line of Credit Line of Credit [Member] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Line of credit facility, borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Debt Instrument, term Debt Instrument, Term Debt instrument, face amount Debt Instrument, Face Amount Borrowing capacity after initial year of term Line Of Credit Facility, Maximum Borrowing Capacity After Initial Year Of Term Line Of Credit Facility, Maximum Borrowing Capacity After Initial Year Of Term Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Weighted average interest rate Debt, Weighted Average Interest Rate Commitment fee percentage on unused portion of the Facility Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Leverage ratio Debt Instrument Covenant Total Leverage Ratio Debt Instrument Covenant Total Leverage Ratio Fixed charge coverage ratio Debt Instrument Covenant Fixed Charge Coverage Ratio Debt Instrument Covenant Fixed Charge Coverage Ratio Leverage ratio election option for four fiscal quarters in event of material acquisition Debt Instrument, Covenant Total Leverage Ratio, Optional Ratio For Four Fiscal Quarters In Event Of Material Acquisition Debt Instrument, Covenant Total Leverage Ratio, Optional Ratio For Four Fiscal Quarters In Event Of Material Acquisition Deferred financing costs Debt Issuance Costs, Gross Document And Entity Information [Abstract] Document And Entity Information [Abstract] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Disposed of by sale, not discontinued operations Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] Government Services Government Services [Member] Government Services [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Sale of Government Services business, consideration Proceeds from Divestiture of Businesses Gain on sale of Government Services business Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Technology & Manufacturing Technology And Manufacturing [Member] Technology And Manufacturing [Member] Education Education [Member] Education [Member] Technical Solutions Technical Solutions [Member] Technical Solutions [Member] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments Operating Segments [Member] Corporate Corporate, Non-Segment [Member] Segment Reconciling Items Segment Reconciling Items [Member] Revenues Segment Reporting Information, Revenue for Reportable Segment [Abstract] Operating profit (loss) Segment Reporting Information, Profit (Loss) [Abstract] Adjustment for tax deductions for energy efficient government buildings, included in Technical Solutions Energy Efficient Government Buildings Tax Credits, Amount Energy Efficient Government Buildings Tax Credits, Amount Operating profit (loss) Adjustment for income from unconsolidated affiliates, net, included in Aviation and Government Services Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Auction Rate Securities Auction Rate Securities [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Retained Earnings Retained Earnings [Member] Number of different auction rate securities issuers Number Of Financial Institution The number of different issuers of the auction rate securities held by the Company. Investment in auction rate securities, original principal amount Available-for-sale Debt Securities, Original Principal Amount This item represents the original cost of debt securities, which are categorized neither as held-to-maturity nor trading, excluding adjustments such as accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. Investment in auction rate securities, amortized cost basis Available-for-sale Debt Securities, Amortized Cost Basis Interest rate reset interval Interest Rate Reset Interval The period of time in which the interest rates for auction rate securities reset through auctions. Available-for-sale debt securities, original par value Available-for-sale Debt Securities, Original Par Value Available-for-sale Debt Securities, Original Par Value Proceeds from sale of AFS securities, debt Proceeds from Sale of Available-for-sale Securities, Debt Investment in auction rate securities, fair value Available-for-sale Securities, Debt Securities Unrealized holding gain (loss) on securities Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax Total amount of other-than-temporary impairment (OTTI) credit loss recognized Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held Acquisitions Business Combination Disclosure [Text Block] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest Rate Swap, Maturity 4/30/2021 Interest Rate Swap, Maturity 4/30/2021 [Member] Interest Rate Swap, Maturity 4/30/2021 [Member] Interest Rate Swap, Maturity 10/31/2021 Interest Rate Swap, Maturity 10/31/2021 [Member] Interest Rate Swap, Maturity 10/31/2021 [Member] Interest Rate Swap, Maturity 4/30/2022 Interest Rate Swap, Maturity 4/30/2022 [Member] Interest Rate Swap, Maturity 4/30/2022 [Member] Interest Rate Swap, Maturity 9/1/2022 Interest Rate Swap, Maturity 9/1/2022 [Member] Interest Rate Swap, Maturity 9/1/2022 [Member] Accumulated Net Gain (Loss) from Cash Flow Hedges Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] Proceeds from termination of interest rate swaps Proceeds From Derivative Instrument, Operating Activities Proceeds From Derivative Instrument, Operating Activities Notional amount Derivative, Notional Amount Derivative, fixed interest rate (percent) Derivative, Fixed Interest Rate Net gains from cash flow hedges recorded in accumulated other comprehensive loss, net of tax Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax Tax related to amounts in accumulated other comprehensive loss AOCI Tax, Attributable to Parent Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, gross Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Gross Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Gross Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net Significant Assumptions Used to Determine Fair Value of Auction Rate Securities Fair Value Inputs, Assets, Quantitative Information [Table Text Block] Income Taxes Income Tax Disclosure [Text Block] Schedule of Other Liabilities [Table] Schedule Of Other Liabilities [Table] Schedule of Other Liabilities [Table] Schedule of Other Liabilities [Line Items] Schedule Of Other Liabilities [Line Items] Schedule of Other Liabilities [Line Items] Self insurance retention amount per-claim Self Insured Retention Amount Per Occurrence Self Insured Retention Amount Per Occurrence Primary policy limit Workers Compensation General Liability and Other Insurable Risks Insurance Policy Limit Represents the policy limit provided by the insurance program for workers' compensation, general liability, and other insurable risks. Insurance policy coverage, general and automobile liability losses Insurance Policy Coverage, General Liability And Automobile Liability Losses Represents commercial insurance umbrella policies that cover general liability and automobile liability losses above primary limits. Insurance policy coverage, property damage Property Damage Policy Limit Represents the policy limit provided by the insurance program for property damage risks. Self insurance retention amount per-claim, medical plan Self Insured Retention Amount Per Participant Per Year For Certain Employee Medical And Dental Programs Self Insured Retention Amount Per Participant Per Year For Certain Employee Medical And Dental Programs Change in reserves for insurance claims Increase in Total Reserve Claims Increase in Total Reserve Claims Increase in Claims Reserve Increase in Claims Reserve Increase in Claims Reserve Insurance reserve adjustment, amount less than prior year adjustment Insurance Reserve, Adjustment Less Than Or (Greater Than) Prior Year Adjustment, Amount Insurance Reserve, Adjustment Less Than Or (Greater Than) Prior Year Adjustment, Amount Basis of Presentation and Significant Accounting Policies Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Letters Of Credit [Table] Letters Of Credit [Table] Letters Of Credit [Table] Instruments Used to Collateralize Insurance Obligations by Type [Axis] Instruments Used to Collateralize Insurance Obligations by Type [Axis] Instruments Used to Collateralize Insurance Obligations by Type [Axis] Instruments Used to Collateralize Insurance Obligations, Type [Domain] Instruments Used to Collateralize Insurance Obligations, Type [Domain] Instruments Used to Collateralize Insurance Obligations, Type [Domain] Standby letters of credit Surety bonds Surety Bond [Member] Restricted insurance deposits Deposits [Member] Letters Of Credit [Line Items] Letters Of Credit [Line Items] Letters Of Credit [Line Items] Instruments used to collateralize insurance obligations Instruments Used To Collateralize Insurance Obligations Instruments Used To Collateralize Insurance Obligations Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable [Table] Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable [Table] Equity Interest Type [Axis] Equity Interest Type [Axis] Equity Interest Issued or Issuable, Type [Domain] Equity Interest Issued or Issuable, Type [Domain] Common Stock Common Stock [Member] Business Acquisition, Equity Interests Issued or Issuable [Line Items] Business Acquisition, Equity Interests Issued or Issuable [Line Items] Shares of ABM common stock, net of shares withheld for taxes (in shares) Business Acquisition, Equity Interest Issued or Issuable, Number of Shares ABM common stock closing market price at acquisition date (usd per share) Business Acquisition, Share Price Fair value of ABM common stock at closing Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Cash consideration Payments to Acquire Businesses, Gross Total consideration transferred Statement of Cash Flows [Abstract] Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] (Income) loss from discontinued operations, net of taxes Adjustments to reconcile income from continuing operations to net cash provided by operating activities of continuing operations Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Deferred income taxes Deferred Income Tax Expense (Benefit) Share-based compensation expense Share-based Compensation Provision for bad debt Provision for Doubtful Accounts Discount accretion on insurance claims Accretion Expense Loss (gain) on sale of assets Gain (Loss) on Disposition of Assets Income from unconsolidated affiliates, net Distributions from unconsolidated affiliates Proceeds from Equity Method Investment, Distribution Changes in operating assets and liabilities, net of effects of acquisitions Increase (Decrease) in Operating Capital [Abstract] Trade accounts receivable Increase (Decrease) in Accounts Receivable Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Other noncurrent assets Increase (Decrease) in Other Noncurrent Assets Trade accounts payable and other accrued liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Insurance claims Increase (Decrease) in Self Insurance Reserve Income taxes payable Increase (Decrease) in Income Taxes Payable Other noncurrent liabilities Increase (Decrease) in Other Noncurrent Liabilities Total adjustments Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities Net cash provided by operating activities of continuing operations Net Cash Provided by (Used in) Operating Activities, Continuing Operations Net cash provided by (used in) operating activities of discontinued operations Cash Provided by (Used in) Operating Activities, Discontinued Operations Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Additions to property, plant and equipment Payments to Acquire Property, Plant, and Equipment Proceeds from sale of assets Proceeds from Sale of Other Assets, Investing Activities Adjustments to purchase and sale of business Divestiture Of Businesses, Adjustments Cash outflow representing an adjustment to a previous divestiture. Purchase of businesses, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Investments in unconsolidated affiliates Payments to Acquire Equity Method Investments Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] (Taxes withheld) and proceeds from issuance of share-based compensation awards, net Payments Related to Tax Withholding for Share-based Compensation Proceeds from issuance of share-based compensation awards, net Excess Tax Benefit from Share-based Compensation, Financing Activities Repurchases of common stock Payments for Repurchase of Common Stock Dividends paid Payments of Ordinary Dividends, Common Stock Deferred financing costs paid Payments of Financing Costs Borrowings from credit facility Proceeds from Issuance of Long-term Debt Repayment of borrowings from credit facility Repayments of Long-term Debt Changes in book cash overdrafts Proceeds from (Repayments of) Bank Overdrafts Financing of energy savings performance contracts Proceeds from Construction Loans Payable Payment for Contingent Consideration Liability, Financing Activities Payment for Contingent Consideration Liability, Financing Activities Repayment of capital lease obligations Repayments of Long-term Capital Lease Obligations Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Effect of exchange rate changes on cash and cash equivalents Effect of Exchange Rate on Cash and Cash Equivalents Net increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of year Cash and cash equivalents at end of period