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INCOME TAXES (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
INCOME TAXES    
Statutory federal tax rate (as a percent) 35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate  
State tax, low end of range of rate (as a percent) 6.00%arcb_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxesLowEndOfRange  
State tax, high end of range of rate (as a percent) 6.50%arcb_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxesHighEndOfRange  
Effective tax (benefit) rate (as a percent) 18.30%us-gaap_EffectiveIncomeTaxRateContinuingOperations (42.00%)us-gaap_EffectiveIncomeTaxRateContinuingOperations
Benefit from reduced state deferred tax liabilities reflecting enactment of lower tax rates in some states (as a percent) 20.90%us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate 1.60%us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate
Federal, state, and foreign income taxes paid $ 1.1us-gaap_IncomeTaxesPaid $ 5.4us-gaap_IncomeTaxesPaid
Federal and state income tax refunds received   $ 2.0us-gaap_ProceedsFromIncomeTaxRefunds