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EMPLOYEE BENEFIT PLANS (Multiemployer Plans) (Details) $ in Thousands |  |  |  |  |  |  |  | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Aug. 01, 2017 | Jan. 31, 2017 | Aug. 01, 2016 | Feb. 01, 2016 | Jan. 31, 2016 | Aug. 01, 2015 | Feb. 01, 2015 | Dec. 31, 2017 USD ($) $ / h plan | Jan. 31, 2017 | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) | Jan. 01, 2017 | Jan. 01, 2016 | Jan. 01, 2015
Multiemployer pension plans | Central States Pension Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |
Multiemployer Plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of contributions to multiemployer pension plan |  |  |  |  |  |  |  | 50.00% |  | 50.00% | 50.00% |  |  |
Asset-Based |  |  |  |  |  |  |  |  |  |  |  |  |  |
Multiemployer Plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum increase in combined contribution rates for health, welfare, and pension benefits each August 1 | $ / h |  |  |  |  |  |  |  | 1.00 |  |  |  |  |  |
Minimum funded percentage of plans in green zone |  |  |  |  |  |  |  | 80.00% |  |  |  |  |  |
Asset-Based | Multiemployer pension plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Multiemployer Plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of multiemployer plans to which ABF Freight currently contributes | plan |  |  |  |  |  |  |  | 25 |  |  |  |  |  |
Maximum funded percentage of plans in yellow zone |  |  |  |  |  |  |  | 80.00% |  |  |  |  |  |
Maximum funded percentage of plans in red zone |  |  |  |  |  |  |  | 65.00% |  |  |  |  |  |
Maximum projected time to insolvency for plans in "critical and declining" status |  |  |  |  |  |  |  | 14 years |  |  |  |  |  |
Maximum projected time to insolvency for plans in "critical and declining" status if additional criteria apply |  |  |  |  |  |  |  | 19 years |  |  |  |  |  |
Threshold ratio of inactive to active participants for greater insolvency period to determine "critical and declining" status |  |  |  |  |  |  |  | 2 |  |  |  |  |  |
Threshold funded percentage for greater insolvency period to determine "critical and declining" status |  |  |  |  |  |  |  | 80.00% |  |  |  |  |  |
Percentage of contributions to the multiemployer pension plans that are in critical and declining status |  |  |  |  |  |  |  | 60.00% |  |  |  |  |  |
Percentage of contributions to the multiemployer pension plans that are in critical status |  |  |  |  |  |  |  | 1.00% |  |  |  |  |  |
Percentage of contributions to the multiemployer pension plans that are in endangered status |  |  |  |  |  |  |  | 6.00% |  |  |  |  |  |
Total contributions to multiemployer plans |  |  |  |  |  |  |  | $ 158,416 |  | $ 154,139 | $ 151,898 |  |  |
Percentage increase in contribution rate for time worked related to benefit costs | 1.70% |  | 0.50% |  |  | 1.20% |  |  |  |  |  |  |  |
Maximum projected time to insolvency without legislative action |  |  |  |  |  |  |  | 10 years |  |  |  |  |  |
Asset-Based | Multiemployer pension plans | Central States Pension Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |
Multiemployer Plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total contributions to multiemployer plans |  |  |  |  |  |  |  | $ 78,230 |  | $ 77,891 | $ 77,491 |  |  |
Threshold percentage of the entity's contributions relative to total fund contributions, which was exceeded during the period |  |  |  |  |  |  |  |  |  | 5.00% | 5.00% |  |  |
Approved increase in contribution (as a percent) | 0.0 |  | 0.0 |  |  | 0.0 |  |  |  |  |  |  |  |
Actuarially certified projected funded percentage of multiemployer pension plan |  |  |  |  |  |  |  |  |  |  |  | 37.80% | 42.10% | 47.90%
Asset-Based | Multiemployer pension plans | Western Conference of Teamsters Pension Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |
Multiemployer Plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total contributions to multiemployer plans |  |  |  |  |  |  |  | 26,320 |  | $ 25,075 | $ 24,474 |  |  |
Approved increase in contribution (as a percent) | 0.0 |  | 0.0 |  |  | 0.0 |  |  |  |  |  |  |  |
Asset-Based | Multiemployer pension plans | Central Pennsylvania Teamsters Pension Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |
Multiemployer Plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total contributions to multiemployer plans |  |  |  |  |  |  |  | 13,391 |  | 13,381 | 13,147 |  |  |
Asset-Based | Multiemployer pension plans | Local 710 Pension Fund |  |  |  |  |  |  |  |  |  |  |  |  |  |
Multiemployer Plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total contributions to multiemployer plans |  |  |  |  |  |  |  | 10,054 |  | 9,670 | 10,020 |  |  |
Threshold percentage of the entity's contributions relative to total fund contributions, which was exceeded during the period |  | 5.00% |  | 5.00% | 5.00% |  | 5.00% |  | 5.00% |  |  |  |  |
Asset-Based | Multiemployer pension plans | All Other Pension Plans in Aggregate |  |  |  |  |  |  |  |  |  |  |  |  |  |
Multiemployer Plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total contributions to multiemployer plans |  |  |  |  |  |  |  | $ 30,421 |  | 28,122 | 26,766 |  |  |
Asset-Based | Multiemployer pension plans | 707 Pension Fund |  |  |  |  |  |  |  |  |  |  |  |  |  |
Multiemployer Plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of contributions to multiemployer pension plan |  |  |  |  |  |  |  | 1.00% |  |  |  |  |  |
Asset-Based | Multiemployer pension plans | New York State Pension Fund |  |  |  |  |  |  |  |  |  |  |  |  |  |
Multiemployer Plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of contributions to multiemployer pension plan |  |  |  |  |  |  |  | 2.00% |  |  |  |  |  |
Asset-Based | Multiemployer health and welfare plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Multiemployer Plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of multiemployer plans to which ABF Freight currently contributes | plan |  |  |  |  |  |  |  | 42 |  |  |  |  |  |
Total contributions to multiemployer plans |  |  |  |  |  |  |  | $ 162,200 |  | $ 153,300 | $ 144,700 |  |  |
Percentage increase in contribution rate for time worked related to benefit costs | 3.90% |  | 3.60% |  |  | 5.80% |  |  |  |  |  |  |  |
Asset-Based | Unionized employees concentration risk | Number of employees |  |  |  |  |  |  |  |  |  |  |  |  |  |
Multiemployer Plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of Asset-Based segment employees covered under collective bargaining agreement with the IBT |  |  |  |  |  |  |  | 83.00% |  |  |  |  |  |

X
- Definition Represents the projected funded percentage of a specified multiemployer pension plan. + References No definition available. + Details
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- Definition Represents the maximum funded percentage of plans in the red zone. + References No definition available. + Details
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- Definition Represents the maximum funded percentage of plans in the yellow zone. + References No definition available. + Details
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- Definition Represents the minimum funded percentage of plans in the yellow zone. + References No definition available. + Details
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- Definition Represents the percentage of the entity's contributions to multiemployer pension plans that are made to the specified plan. + References No definition available. + Details
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- Definition Represents the percentage of the entity's contributions to multiemployer pension plans that are made to plans in critical and declining status. + References No definition available. + Details
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- Definition Represents the percentage of the entity's contributions to multiemployer pension plans that are made to plans in critical status. + References No definition available. + Details
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- Definition Represents the percentage of the entity's contributions to multiemployer pension plans that are made to plans in endangered status. + References No definition available. + Details
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- Definition Approved increase in employer's contractual contribution rate to multiemployer plan by Negotiating Committee of Plan. + References No definition available. + Details
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- Definition Represents the threshold percentage of the entity's contributions to the plan relative to total contributions received by the plan, which was exceeded during the period, triggering disclosure of the plan year. + References No definition available. + Details
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- Definition The threshold funded percentage of plans, below which a higher maximum period for insolvency is used to determine "critical and declining" status. + References No definition available. + Details
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- Definition The threshold ratio of inactive participants to active participants, above which a higher maximum period for insolvency is used to determine "critical and declining" status. + References No definition available. + Details
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- Definition The maximum annual increase in the employer's combined health, welfare and pension benefit contribution rate for multiemployer plans. + References No definition available. + Details
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- Definition The maximum period within which a plan in "critical and declining" status is expected to become insolvent, unless additional criteria relating to ratio of inactive to active participants or funded percentage are applicable. + References No definition available. + Details
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- Definition The maximum period within which a plan in "critical and declining" status is expected to become insolvent, if additional criteria relating to ratio of inactive to active participants or funded percentage are applicable. + References No definition available. + Details
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- Definition The maximum period within which a plan is expected to become insolvent without legislation action. + References No definition available. + Details
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- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6351-108592 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13531-108611 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6404-108592 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13537-108611 + Details
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- Definition Increase (decrease) in employer's contractual contribution rate to multiemployer plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 11 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450702-114947 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450673-114947 + Details
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