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LEGAL PROCEEDINGS, ENVIRONMENTAL MATTERS, AND OTHER EVENTS (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
state
tank
Dec. 31, 2014
Underground fuel storage tanks    
Environmental Matters    
Number of underground tanks where the company's subsidiaries store fuel for use in tractors and trucks 63arcb_UndergroundFuelStorageTanksNumber
/ us-gaap_EnvironmentalRemediationContingencyAxis
= arcb_UndergroundFuelStorageTanksMember		  
Number of states in which underground tanks are located 19arcb_UndergroundFuelStorageTanksLocationsNumberOfStates
/ us-gaap_EnvironmentalRemediationContingencyAxis
= arcb_UndergroundFuelStorageTanksMember		  
Clean Water Act | Freight Transportation (ABF Freight)    
Environmental Matters    
Reserve for environmental contingencies 0us-gaap_AccruedEnvironmentalLossContingenciesCurrent
/ us-gaap_EnvironmentalRemediationContingencyAxis
= arcb_CleanWaterActLitigationMember
/ us-gaap_StatementBusinessSegmentsAxis
= arcb_FreightTransportationMember		  
Environmental cleanup costs    
Environmental Matters    
Reserve for environmental contingencies 0.9us-gaap_AccruedEnvironmentalLossContingenciesCurrent
/ us-gaap_EnvironmentalRemediationContingencyAxis
= arcb_EnvironmentalCleanupCostsMember		 $ 0.8us-gaap_AccruedEnvironmentalLossContingenciesCurrent
/ us-gaap_EnvironmentalRemediationContingencyAxis
= arcb_EnvironmentalCleanupCostsMember