Debt Instrument, Variable Rate, Minimum

No definition available.

Name:	abg_DebtInstrumentVariableRateMinimum
Namespace Prefix:	abg_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of Credit Facility, Number of Quarterly Principal Payments

+ References

No definition available.

+ Details

Name:	abg_LineOfCreditFacilityNumberOfQuarterlyPrincipalPayments
Namespace Prefix:	abg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of Credit Facility, Quarterly Principal Payments as Percent of Initial Amount

+ References

No definition available.

+ Details

Name:	abg_LineofCreditFacilityQuarterlyPrincipalPaymentsasPercentofInitialAmount
Namespace Prefix:	abg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 3: 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(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Namespace Prefix:
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Balance Type:
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- Details

Name:	srt_RangeAxis=srt_MinimumMember
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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_VariableRateAxis=abg_SOFRPlusBasisSpreadMember
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Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_VariableRateAxis=abg_BaseRateComponentFederalFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Data Type:	na
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- Details

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Namespace Prefix:
Data Type:	na
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- Details

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Namespace Prefix:
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- Details

Name:	us-gaap_VariableRateAxis=abg_OneMonthLondonInterbankOfferedRateMember
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- Details

Name:	us-gaap_LineOfCreditFacilityAxis=abg_WellsFargoBankNationalAssociationMember
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DEBT - 2021 BofA Real Estate Facility (Details) - 2021 BofA Real Estate Facility $ in Millions	May 25, 2022	May 20, 2021 USD ($) numberOfPayments	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Debt Instrument [Line Items]
Basis spread on variable rate	65.00%
Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	100.00%
SOFR
Debt Instrument [Line Items]
Basis spread on variable rate	10.00%
SOFR \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	10.00%
Base Rate
Debt Instrument [Line Items]
Debt instrument, variable rate, minimum	1.00
SOFR Plus Basis Spread
Debt Instrument [Line Items]
Basis spread on variable rate	165.00%
Base Rate Component, Federal Funds \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	50.00%
Bank of America
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 184.4
Number of quarterly principal payments \| numberOfPayments		39
Quarterly principal payments as percent of initial amount		1.00%
Bank of America \| Base Rate \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate		0.65%
Bank of America \| Federal Funds
Debt Instrument [Line Items]
Basis spread on variable rate		0.50%
Bank of America \| LIBOR \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate		1.65%
Bank of America \| One month LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		1.00%
Wells Fargo
Debt Instrument [Line Items]
Long-term debt, gross			$ 173.3	$ 180.7