XML 40 R24.htm IDEA: XBRL DOCUMENT
v2.4.0.8

PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2014
PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS |
Summary of the components of net periodic benefit cost |
|  | Three Months Ended September 30 |
|  | Nonunion Defined |  | Supplemental |  | Postretirement |
|  | Benefit Pension Plan |  | Benefit Plan |  | Health Benefit Plan |
|  | 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013 |
|  | (in thousands) |
Service cost |  | $ | — |  | $ | — |  | $ | — |  | $ | — |  | $ | 70 |  | $ | 82 |
Interest cost |  | 1,401 |  | 2,039 |  | 49 |  | 37 |  | 197 |  | 188 |
Expected return on plan assets |  | (2,544 | ) | (3,438 | ) | — |  | — |  | — |  | — |
Amortization of prior service credit |  | — |  | — |  | — |  | — |  | (47 | ) | (47 | )
Pension settlement expense |  | 805 |  | 1,834 |  | — |  | — |  | — |  | — |
Amortization of net actuarial loss |  | 595 |  | 961 |  | 57 |  | 65 |  | 23 |  | 134 |
Net periodic benefit cost |  | $ | 257 |  | $ | 1,396 |  | $ | 106 |  | $ | 102 |  | $ | 243 |  | $ | 357 |
|  | Nine Months Ended September 30 |
|  | Nonunion Defined |  | Supplemental |  | Postretirement |
|  | Benefit Pension Plan |  | Benefit Plan |  | Health Benefit Plan |
|  | 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013 |
|  | (in thousands) |
Service cost |  | $ | — |  | $ | 4,734 |  | $ | — |  | $ | — |  | $ | 210 |  | $ | 248 |
Interest cost |  | 4,643 |  | 5,884 |  | 147 |  | 112 |  | 591 |  | 563 |
Expected return on plan assets |  | (7,980 | ) | (9,747 | ) | — |  | — |  | — |  | — |
Amortization of prior service credit |  | — |  | — |  | — |  | — |  | (142 | ) | (142 | )
Pension settlement expense |  | 5,405 |  | 1,834 |  | — |  | — |  | — |  | — |
Amortization of net actuarial loss |  | 1,729 |  | 6,388 |  | 170 |  | 195 |  | 69 |  | 401 |
Net periodic benefit cost |  | $ | 3,797 |  | $ | 9,093 |  | $ | 317 |  | $ | 307 |  | $ | 728 |  | $ | 1,070 |
Schedule of changes in the PBO and plan assets of the nonunion defined benefit pension plan |
|  | Nonunion Defined |
|  | Benefit Pension Plan |
|  | (in thousands) |
Change in projected benefit obligation |  |  |
Projected benefit obligation at December 31, 2013 |  | $ | 211,660 |
Interest cost |  | 4,643 |
Actuarial loss(1) |  | 10,413 |
Benefits paid(2) |  | (54,593 | )
Projected benefit obligation at September 30, 2014 |  | 172,123 |
Change in plan assets |  |  |
Fair value of plan assets at December 31, 2013 |  | 207,613 |
Actual return on plan assets |  | 5,182 |
Benefits paid(2) |  | (54,593 | )
Fair value of plan assets at September 30, 2014 |  | 158,202 |
Funded status at September 30, 2014(3) |  | $ | (13,921 | )
Accumulated benefit obligation |  | $ | 172,123 |
| (1) |  | Net actuarial loss from remeasurement upon settlements was primarily impacted by changes in the discount rate at each remeasurement date. The discount rate used to remeasure the PBO upon settlement at the September 30, 2014 measurement date was 3.4%, compared to 3.8% at the December 31, 2013 measurement date.
| (2) |  | Includes purchase of nonparticipating annuity contract, lump-sum distributions, and periodic payments made by the plan during the nine months ended September 30, 2014.
| (3) |  | Noncurrent liability recognized within pension and postretirement liabilities in the accompanying consolidated balance sheet at September 30, 2014.

X
- Definition Tabular disclosure of net funded status of pension plans and/or other employee benefit plans and disclosure of accumulated benefit obligation. + References No definition available. + Details
Name: | arcb_ScheduleOfNetFundedStatusAndChangesInAccumulatedBenefitObligationAndPlanAssetsTableTextBlock
Namespace Prefix: | arcb_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DefinedBenefitPensionPlansAndDefinedBenefitPostretirementPlansDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfNetBenefitCostsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration