XML 113 R88.htm IDEA: XBRL DOCUMENT
v3.20.4

Share-Based Compensation Plans - Narrative (Details) - USD ($) | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Oct. 31, 2020 | Mar. 31, 2018 | Mar. 31, 2016 | May 01, 2006
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Holding period for shares purchased in program | 6 months |  |  |
2006 Equity Plan |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Number of shares authorized (in shares) |  | 13,475,265 |  |
Number of shares available for grant (in shares) | 2,086,078 |  |  |
2004 Employee Stock Purchase Plan |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Number of shares authorized (in shares) |  |  | 4,000,000 |
Fair value percentage of common stock price |  |  |  | 95.00%
Employee contribution percentage |  |  |  | 10.00%
Maximum annual employee contribution |  |  |  | $ 25,000
Number of shares unissued (in shares) | 599,159 |  |  |

X
- Definition Share Based Compensation Fair Value Percentage of Common Stock Price + References No definition available. + Details
Name: | abm_ShareBasedCompensationFairValuePercentageofCommonStockPrice
Namespace Prefix: | abm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Share-based Compensation Arrangement by Share-based Payment Award, Holding Period On Employee Stock Purchase + References No definition available. + Details
Name: | abm_SharebasedCompensationArrangementbySharebasedPaymentAwardHoldingPeriodOnEmployeeStockPurchase
Namespace Prefix: | abm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Stock Based Compensation Maximum Employee Contribution + References No definition available. + Details
Name: | abm_StockBasedCompensationMaximumEmployeeContribution
Namespace Prefix: | abm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Stock Based Compensation Maximum Employee Contribution Percentage + References No definition available. + Details
Name: | abm_StockBasedCompensationMaximumEmployeeContributionPercentage
Namespace Prefix: | abm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate number of common shares reserved for future issuance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares authorized for issuance under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_PlanNameAxis=abm_TwoThousandSixEquityIncentivePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=abm_TwoThousandFourEmployeeStockPurchasePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |