LONG-TERM DEBT AND FINANCING ARRANGEMENTS (Summary) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Long-term debt obligations
Long-term debt	$ 212,509	$ 127,730
Less current portion	44,910	25,256
Long-term debt, less current portion	$ 167,599	102,474
Weighted-average interest rate (as a percent)	2.10%
Payments under long-term debt obligations
2016	$ 48,512
2017	43,698
2018	59,130
2019	2,732
2020	70,025
Total payments	224,097
Less amounts representing interest	11,588
Long-term debt	212,509	127,730
Credit Facility
Long-term debt obligations
Long-term debt	$ 70,000
Interest rate (as a percent)	1.70%
Payments under long-term debt obligations
2016	$ 1,375
2017	1,802
2018	2,101
2019	2,259
2020	70,006
Total payments	77,543
Less amounts representing interest	7,543
Long-term debt	70,000
Term Loan
Long-term debt obligations
Long-term debt		70,000
Payments under long-term debt obligations
Long-term debt		70,000
Accounts receivable securitization program
Long-term debt obligations
Long-term debt	$ 35,000
Interest rate (as a percent)	1.10%
Payments under long-term debt obligations
2016	$ 536
2017	750
2018	35,002
Total payments	36,288
Less amounts representing interest	1,288
Long-term debt	35,000
Notes payable
Long-term debt obligations
Long-term debt	$ 106,703	56,759
Weighted-average interest rate (as a percent)	1.90%
Payments under long-term debt obligations
Long-term debt	$ 106,703	56,759
Notes payable \| Revenue equipment
Long-term debt obligations
Long-term debt	106,703
Payments under long-term debt obligations
2016	46,388
2017	40,927
2018	21,801
2019	241
Total payments	109,357
Less amounts representing interest	2,654
Long-term debt	106,703
Capital lease obligations
Long-term debt obligations
Long-term debt	$ 806	971
Weighted-average interest rate (as a percent)	5.80%
Payments under long-term debt obligations
Long-term debt	$ 806	$ 971
Capital lease obligations \| Land and structures (terminals)
Long-term debt obligations
Long-term debt	806
Payments under long-term debt obligations
2016	213
2017	219
2018	226
2019	232
2020	19
Total payments	909
Less amounts representing interest	103
Long-term debt	$ 806

-- None. No documentation exists for this element. --

No definition available.

Name:	arcb_MaturitiesOfLongTermDebtAndFutureMinimumPaymentsUnderCapitalLeasesAbstract
Namespace Prefix:	arcb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents aggregate future amounts due of contractually required rental payments on leases meeting the criteria for capitalization and maturities on long-term debt, including interest.

+ References

No definition available.

+ Details

Name:	arcb_MaturitiesOfLongTermDebtAndFutureMinimumPaymentsUnderCapitalLeasesDue
Namespace Prefix:	arcb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents amount of contractually required rental payments on leases meeting the criteria for capitalization and maturities on long-term debt, including interest, due within one year of the latest balance sheet date presented.

+ References

No definition available.

+ Details

Name:	arcb_MaturitiesOfLongTermDebtAndFutureMinimumPaymentsUnderCapitalLeasesDueCurrent
Namespace Prefix:	arcb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents amount of contractually required rental payments on leases meeting the criteria for capitalization and maturities on long-term debt, including interest, due after four and within five years of the latest balance sheet date presented.

+ References

No definition available.

+ Details

Name:	arcb_MaturitiesOfLongTermDebtAndFutureMinimumPaymentsUnderCapitalLeasesDueInFiveYears
Namespace Prefix:	arcb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents amount of contractually required rental payments on leases meeting the criteria for capitalization and maturities on long-term debt, including interest, due after three and within four years of the latest balance sheet date presented.

+ References

No definition available.

+ Details

Name:	arcb_MaturitiesOfLongTermDebtAndFutureMinimumPaymentsUnderCapitalLeasesDueInFourYears
Namespace Prefix:	arcb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents amount of contractually required rental payments on leases meeting the criteria for capitalization and maturities on long-term debt, including interest, due after two and within three years of the latest balance sheet date presented.

+ References

No definition available.

+ Details

Name:	arcb_MaturitiesOfLongTermDebtAndFutureMinimumPaymentsUnderCapitalLeasesDueInThreeYears
Namespace Prefix:	arcb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents amount of contractually required rental payments on leases meeting the criteria for capitalization and maturities on long-term debt, including interest, due after one and within two years of the latest balance sheet date presented.

+ References

No definition available.

+ Details

Name:	arcb_MaturitiesOfLongTermDebtAndFutureMinimumPaymentsUnderCapitalLeasesDueInTwoYears
Namespace Prefix:	arcb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the interest amount by which the contractually required payments on capital leases and long-term debt are reduced to calculate the present value of the long-term debt and capital lease obligations.

+ References

No definition available.

+ Details

Name:	arcb_MaturitiesOfLongTermDebtAndFutureMinimumPaymentsUnderCapitalLeasesInterestIncludedInPayments
Namespace Prefix:	arcb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 6
-Section H

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt and capital leases due within one year or the normal operating cycle, if longer.

+ References

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt and capital lease obligations including current maturities.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=arcb_AccountsReceivableSecuritizationProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_NotesPayableOtherPayablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_VehiclesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_CapitalLeaseObligationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_LandBuildingsAndImprovementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: