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v3.20.2

INCOME TAXES (Tax Rate) (Details) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
INCOME TAXES |  |  |  |
Effective tax rate (as a percent) | 24.90% | 30.30% | 24.30% | 28.30%
State tax, low end of range of rate (as a percent) |  |  | 6.00% |
State tax, high end of range of rate (as a percent) |  |  | 6.50% |

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- Definition Represents the high end of the range of average state tax rates during the period. + References No definition available. + Details
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- Definition Represents the low end of the range of average state tax rates during the period. + References No definition available. + Details
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Namespace Prefix: | arcb_
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X
- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319 + Details
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- References No definition available. + Details
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