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PENSION AND OTHER POSTRETIREMENT PLANS - Financial Assets Measured At Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | --- | ---
Pension Benefits |  |  |
Employee benefits |  |  |
Total plan assets | $ 44,060 | $ 39,745 | $ 33,874
Carrying Amount | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 44,060 | 39,745 |
Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 26,876 | 25,050 |
Significant Other Observable Inputs (Level 2) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 17,184 | 14,695 |
Significant Unobservable Inputs (Level 3) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
Cash and cash equivalents | Carrying Amount | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 2,452 | 1,444 |
Cash and cash equivalents | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
Cash and cash equivalents | Significant Other Observable Inputs (Level 2) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 2,452 | 1,444 |
Cash and cash equivalents | Significant Unobservable Inputs (Level 3) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
Equity Securities | Carrying Amount | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 25,023 | 23,026 |
Equity Securities | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 25,023 | 23,026 |
Equity Securities | Significant Other Observable Inputs (Level 2) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
Equity Securities | Significant Unobservable Inputs (Level 3) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
U.S. large cap | Carrying Amount | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 15,449 | 12,097 |
U.S. large cap | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 15,449 | 12,097 |
U.S. large cap | Significant Other Observable Inputs (Level 2) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
U.S. large cap | Significant Unobservable Inputs (Level 3) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
U.S. Mid cap/small cap | Carrying Amount | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 3,471 | 4,195 |
U.S. Mid cap/small cap | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 3,471 | 4,195 |
U.S. Mid cap/small cap | Significant Other Observable Inputs (Level 2) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
U.S. Mid cap/small cap | Significant Unobservable Inputs (Level 3) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
International | Carrying Amount | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 6,029 | 6,320 |
International | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 6,029 | 6,320 |
International | Significant Other Observable Inputs (Level 2) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
International | Significant Unobservable Inputs (Level 3) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
Equities blend | Carrying Amount | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 74 | 414 |
Equities blend | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 74 | 414 |
Equities blend | Significant Other Observable Inputs (Level 2) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
Equities blend | Significant Unobservable Inputs (Level 3) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
Fixed income securities | Carrying Amount | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 16,585 | 15,275 |
Fixed income securities | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 1,853 | 2,024 |
Fixed income securities | Significant Other Observable Inputs (Level 2) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 14,732 | 13,251 |
Fixed income securities | Significant Unobservable Inputs (Level 3) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
Corporate | Carrying Amount | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 1,853 | 2,024 |
Corporate | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 1,853 | 2,024 |
Corporate | Significant Other Observable Inputs (Level 2) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
Corporate | Significant Unobservable Inputs (Level 3) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
Government | Carrying Amount | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 2,342 | 2,926 |
Government | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
Government | Significant Other Observable Inputs (Level 2) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 2,342 | 2,926 |
Government | Significant Unobservable Inputs (Level 3) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
Mortgage-backed | Carrying Amount | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 2,325 | 1,033 |
Mortgage-backed | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
Mortgage-backed | Significant Other Observable Inputs (Level 2) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 2,325 | 1,033 |
Mortgage-backed | Significant Unobservable Inputs (Level 3) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
High yield bonds and bond funds | Carrying Amount | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 10,065 | 9,292 |
High yield bonds and bond funds | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 0 | 0 |
High yield bonds and bond funds | Significant Other Observable Inputs (Level 2) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | 10,065 | 9,292 |
High yield bonds and bond funds | Significant Unobservable Inputs (Level 3) | Recurring basis |  |  |
Employee benefits |  |  |
Total plan assets | $ 0 | $ 0 |

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