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PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS (Multiemployer Plans) (Details) $ in Thousands |  | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Aug. 01, 2018 | Jun. 30, 2018 USD ($) | Sep. 30, 2018 USD ($) | Sep. 30, 2018 USD ($) plan | Dec. 31, 2017
Multiemployer Plans |  |  |  |  |
Multiemployer pension fund withdrawal liability charge (pre-tax) |  |  |  | $ 37,922 |
Multiemployer pension plans | Asset-Based |  |  |  |  |
Multiemployer Plans |  |  |  |  |
Number of multiemployer plans to which ABF Freight currently contributes | plan |  |  |  | 25 |
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% |
Multiemployer pension plans | Central States Pension Plan | Asset-Based |  |  |  |  |
Multiemployer Plans |  |  |  |  |
Approximate proportion of multiemployer pension plan contributions (as a percent) |  |  |  | 50.00% |
Multiemployer pension plans | New England Pension Fund | Asset-Based |  |  |  |  |
Multiemployer Plans |  |  |  |  |
Approximate proportion of multiemployer pension plan contributions (as a percent) |  |  |  |  | 3.00%
Contribution rate frozen period (in years) | 10 years |  |  |  |
Multiemployer pension fund withdrawal liability charge (pre-tax) |  | $ 37,900 |  |  |
Initial lump sum payment of withdrawal liability |  |  | $ 15,100 |  |
Withdrawal liability monthly payments period (in years) |  | 23 years |  |  |
Aggregate present value of monthly payments |  | $ 22,800 |  |  |
Outstanding withdrawal liability |  |  | 22,700 | $ 22,700 |
Fair value of withdrawal obligation |  |  | $ 23,000 | $ 23,000 |
Discount rate (as a percent) |  |  | 4.40% | 4.40% |
Multiemployer pension plans | New England Pension Fund | Asset-Based | Accrued expenses |  |  |  |  |
Multiemployer Plans |  |  |  |  |
Outstanding withdrawal liability |  |  | $ 500 | $ 500 |
Multiemployer pension plans | New England Pension Fund | Asset-Based | Other long-term liabilities |  |  |  |  |
Multiemployer Plans |  |  |  |  |
Outstanding withdrawal liability |  |  | $ 22,200 | $ 22,200 |

X
- Definition Amount of expenses associated with multiemployer pension fund withdrawal liability. + 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 Discount rate applied to the undiscounted amount of future payments due to determine the present value of the multiemployer plan withdrawal liability recorded as of the balance sheet date. + References No definition available. + Details
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- Definition The period for which contribution rate is frozen under multiemployer plan agreement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + 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 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 period of time over which monthly payments have to be made for withdrawal liability settlement for multiemployer plan, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Represents the number of multiemployer plans to which the reporting entity currently contributes. + References No definition available. + Details
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- Definition Amount of cash outflow for payment of withdrawal liability from multiemployer plan + References No definition available. + Details
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- Definition The aggregate present value of the monthly payments for the multiemployer plan withdrawal liability. + References No definition available. + Details
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- Definition Fair value of the obligation recognized by withdrawing from a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers. + References No definition available. + Details
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- Definition Amount of the obligation recognized by withdrawing from a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers. + References No definition available. + Details
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