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COMPONENTS OF PENSION PLAN NET PERIODIC BENEFIT COSTS (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Components of net periodic benefit cost: |  |  |  |
Interest cost | $ 1,030 | $ 1,217 | $ 3,138 | $ 3,649
Expected return on plan assets | (1,413) | (1,233) | (4,396) | (3,699)
Amortization of prior service cost | 47 | 46 | 140 | 139
Amortization of net loss | 969 | 980 | 3,096 | 2,941
Net periodic benefit cost | $ 633 | $ 1,010 | 1,978 | $ 3,030
2019 plan year |  |  |  |
Components of net periodic benefit cost: |  |  |  |
Employer contribution |  |  | $ 1,700 |

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