INCOME TAXES - Stock Compensation (Details)	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
INCOME TAXES
Tax benefit for settlement of stock awards (as a percent)	5.20%	2.80%	2.10%

Tax expense (benefit) for settlement of stock awards including both federal and state taxes as a percent.

No definition available.

Name:	arcb_TaxExpenseBenefitSettlementOfStockAwardsPercentage
Namespace Prefix:	arcb_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration