EMPLOYEE BENEFIT PLANS - Deferred Comp Plans (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Deferred salary agreements
Deferred Compensation Plans
Recorded liabilities	$ 1.1	$ 1.3
Voluntary Savings Plan - mutual funds held in trust
Deferred Compensation Plans
Minimum period for election to defer receipt of a portion of salary and incentive compensation	6 months
Voluntary Savings Plan - mutual funds held in trust \| Other long-term assets
Deferred Compensation Plans
VSP assets	$ 4.6	4.0
Voluntary Savings Plan - mutual funds held in trust \| Other long-term liabilities
Deferred Compensation Plans
VSP liabilities	$ 4.6	$ 4.0

Represents the minimum period prior to the end of the performance period for making an election to defer receipt of a portion of salary and incentive compensation.

No definition available.

+ Details

Name:	arcb_DeferredCompensationPlanMinimumPeriodForElectionToDeferBenefits
Namespace Prefix:	arcb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements payable beyond one year (or the operating cycle, if longer).

+ References

No definition available.

+ Details

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

- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

+ References

No definition available.

+ Details

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

- Definition

Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(17))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_DeferredCompensationPlanAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsByTypeOfDeferredCompensationAxis=arcb_DeferredSalaryAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsByTypeOfDeferredCompensationAxis=arcb_VoluntarySavingsPlanMutualFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: