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ACCOUNTING POLICIES (Details 4) (Nonunion Defined Benefit Pension Plan)	0 Months Ended
	Jun. 30, 2013
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

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

X

- Details

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