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ACCOUNTING POLICIES (Pension) (Details) | Jun. 30, 2013
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Nonunion Defined Benefit Pension Plan |
Nonunion Defined Benefit Pension, Supplemental Benefit, and Postretirement Health Plans |
Period of estimate of future compensation rates used to establish the assumed rate of compensation increase | 2 years

X
- Definition Represents the period of estimate of future compensation rates used to establish the assumed rate of compensation increase. + References No definition available. + Details
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Namespace Prefix: | arcb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedInCalculationsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |