XML 63 R43.htm IDEA: XBRL DOCUMENT
v3.10.0.1

ACCOUNTING POLICIES (Concentration) (Details) - Minimum | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Revenues | Customer concentration risk |  |  |
Concentration of Credit Risk |  |  |
Percentage for concentration of credit risk disclosure | 5.00% | 5.00% | 5.00%
Accounts receivable | Credit concentration risk |  |  |
Concentration of Credit Risk |  |  |
Percentage for concentration of credit risk disclosure | 6.00% | 6.00% |

X
- Definition Threshold percentage which the entity uses for disclosure. + References No definition available. + Details
Name: | arcb_ThresholdForDisclosurePercentage
Namespace Prefix: | arcb_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ConcentrationRiskLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueServicesNetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_AccountsReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CreditConcentrationRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |