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PENSION PLAN AND OTHER BENEFIT PLANS - Amounts Recognized, Assumptions Used, Target and Actual Allocation, Fair Value, Estimated Future Benefit Payments, and Other Disclosures (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Net periodic benefit cost [Abstract] |  |  |
Service cost | $ 0 | $ 0 |
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss): [Abstract] |  |  |
Net actuarial (gain) loss | 506 | (626) | $ (711)
Recognized actuarial loss | 300 | 312 | 318
Prior service credit | 0 | 0 | 0
Amortization of prior service benefit | (220) | (220) | (220)
Total before tax effect | $ 586 | (534) | 215
Unrecognized net gain or loss increase threshold percentage for amortization of obligation (in hundredths) | 10.00% |  |
Pension Plan |  |  |
Amount recognized in accumulated other comprehensive income [Abstract] |  |  |
Net actuarial loss | $ 8,602 | 9,352 |
Prior service cost | 0 | 0 |
Total before tax effects | 8,602 | 9,352 |
Accumulated benefit obligation | 42,800 | 39,900 |
Net periodic benefit cost [Abstract] |  |  |
Service cost | 0 | 0 | 0
Interest cost | 1,300 | 1,522 | 1,551
Expected return on plan assets | (2,444) | (2,221) | (3,309)
Recognized actuarial loss | 213 | 204 | 188
Amortization of prior service cost | 0 | 0 | 0
Recognized (gain) loss due to settlements | 0 | 0 | 828
Net periodic cost (benefit) | (931) | (495) | (742)
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss): [Abstract] |  |  |
Net actuarial (gain) loss | (538) | 481 | 736
Recognized actuarial loss | (213) | (204) | (1,016)
Amortization of prior service benefit | 0 | 0 | 0
Total before tax effect | (751) | 277 | (280)
Total recognized in net (benefit) cost and other comprehensive income (loss) (before tax effect) | $ (1,682) | $ (218) | $ (1,022)
Weighted-average assumptions for net periodic cost [Abstract] |  |  |
Discount rate | 3.33% | 4.35% | 3.74%
Expected return on assets | 5.50% | 5.50% | 7.25%
Discount rate | 2.61% | 3.33% | 4.35%
Target allocations of plan assets [Abstract] |  |  |
Percentage of plan assets (in hundredths) | 100.00% | 100.00% |
Expected return on assets | 5.50% | 5.50% | 7.25%
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | $ 50,134 | $ 45,557 | $ 41,476
Estimated benefit payments for each of next five years and aggregate amount expected to be paid [Abstract] |  |  |
2021 | 2,273 |  |
2022 | 2,279 |  |
2023 | 2,276 |  |
2024 | 2,283 |  |
2025 | 2,284 |  |
2026-2030 | 11,379 |  |
Pension Plan | Carrying Value |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 50,134 | 45,557 |
Pension Plan | Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 47,541 | 41,477 |
Pension Plan | Fair Value | Significant Other Observable Inputs (Level 2) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 2,593 | 4,080 |
Pension Plan | Fair Value | Significant Unobservable Inputs (Level 3) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | $ 0 | $ 0 |
Pension Plan | Large-Cap Domestic Equities |  |  |
Weighted-average assumptions for net periodic cost [Abstract] |  |  |
Expected return on assets | 8.70% |  |
Target allocations of plan assets [Abstract] |  |  |
Percentage of plan assets (in hundredths) | 43.00% | 38.00% |
Expected return on assets | 8.70% |  |
Pension Plan | Large-Cap Domestic Equities | Minimum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 20.00% |  |
Pension Plan | Large-Cap Domestic Equities | Maximum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 50.00% |  |
Pension Plan | Mid-Cap Domestic Equities |  |  |
Weighted-average assumptions for net periodic cost [Abstract] |  |  |
Expected return on assets | 9.40% |  |
Target allocations of plan assets [Abstract] |  |  |
Percentage of plan assets (in hundredths) | 2.00% | 2.00% |
Expected return on assets | 9.40% |  |
Pension Plan | Mid-Cap Domestic Equities | Minimum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 0.00% |  |
Pension Plan | Mid-Cap Domestic Equities | Maximum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 15.00% |  |
Pension Plan | Small-Cap Domestic Equities |  |  |
Weighted-average assumptions for net periodic cost [Abstract] |  |  |
Expected return on assets | 8.80% |  |
Target allocations of plan assets [Abstract] |  |  |
Percentage of plan assets (in hundredths) | 3.00% | 2.00% |
Expected return on assets | 8.80% |  |
Pension Plan | Small-Cap Domestic Equities | Minimum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 0.00% |  |
Pension Plan | Small-Cap Domestic Equities | Maximum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 10.00% |  |
Pension Plan | Equity Securities - International Companies |  |  |
Weighted-average assumptions for net periodic cost [Abstract] |  |  |
Expected return on assets | 5.10% |  |
Target allocations of plan assets [Abstract] |  |  |
Percentage of plan assets (in hundredths) | 3.00% | 8.00% |
Expected return on assets | 5.10% |  |
Pension Plan | Equity Securities - International Companies | Minimum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 0.00% |  |
Pension Plan | Equity Securities - International Companies | Maximum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 20.00% |  |
Pension Plan | Intermediate Fixed Income |  |  |
Weighted-average assumptions for net periodic cost [Abstract] |  |  |
Expected return on assets | 4.70% |  |
Target allocations of plan assets [Abstract] |  |  |
Percentage of plan assets (in hundredths) | 45.00% | 45.00% |
Expected return on assets | 4.70% |  |
Pension Plan | Intermediate Fixed Income | Minimum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 30.00% |  |
Pension Plan | Intermediate Fixed Income | Maximum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 70.00% |  |
Pension Plan | Alternative Assets |  |  |
Weighted-average assumptions for net periodic cost [Abstract] |  |  |
Expected return on assets | 0.00% |  |
Target allocations of plan assets [Abstract] |  |  |
Percentage of plan assets (in hundredths) | 0.00% | 0.00% |
Expected return on assets | 0.00% |  |
Pension Plan | Alternative Assets | Minimum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 0.00% |  |
Pension Plan | Alternative Assets | Maximum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 10.00% |  |
Pension Plan | Cash |  |  |
Weighted-average assumptions for net periodic cost [Abstract] |  |  |
Expected return on assets | 1.30% |  |
Target allocations of plan assets [Abstract] |  |  |
Percentage of plan assets (in hundredths) | 4.00% | 5.00% |
Expected return on assets | 1.30% |  |
Pension Plan | Cash | Minimum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 0.00% |  |
Pension Plan | Cash | Maximum |  |  |
Target allocations of plan assets [Abstract] |  |  |
Target allocation, minimum (in hundredths) | 20.00% |  |
Pension Plan | Cash | Carrying Value |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | $ 2,047 | $ 2,210 |
Pension Plan | Cash | Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 2,047 | 2,210 |
Pension Plan | Cash | Fair Value | Significant Other Observable Inputs (Level 2) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Plan | Cash | Fair Value | Significant Unobservable Inputs (Level 3) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Plan | Equity Securities - U.S. Companies | Carrying Value |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 21,716 | 17,939 |
Pension Plan | Equity Securities - U.S. Companies | Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 21,716 | 17,939 |
Pension Plan | Equity Securities - U.S. Companies | Fair Value | Significant Other Observable Inputs (Level 2) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Plan | Equity Securities - U.S. Companies | Fair Value | Significant Unobservable Inputs (Level 3) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Plan | Mutual Funds | Carrying Value |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 23,778 | 21,328 |
Pension Plan | Mutual Funds | Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 23,778 | 21,328 |
Pension Plan | Mutual Funds | Fair Value | Significant Other Observable Inputs (Level 2) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Plan | Mutual Funds | Fair Value | Significant Unobservable Inputs (Level 3) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Plan | U.S. Treasuries/Government Bonds | Carrying Value |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 2,318 | 3,054 |
Pension Plan | U.S. Treasuries/Government Bonds | Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Plan | U.S. Treasuries/Government Bonds | Fair Value | Significant Other Observable Inputs (Level 2) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 2,318 | 3,054 |
Pension Plan | U.S. Treasuries/Government Bonds | Fair Value | Significant Unobservable Inputs (Level 3) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Plan | Corporate bonds and notes | Carrying Value |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 275 | 1,026 |
Pension Plan | Corporate bonds and notes | Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Plan | Corporate bonds and notes | Fair Value | Significant Other Observable Inputs (Level 2) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 275 | 1,026 |
Pension Plan | Corporate bonds and notes | Fair Value | Significant Unobservable Inputs (Level 3) |  |  |
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Defined Benefit Health Care Plan |  |  |
Amount recognized in accumulated other comprehensive income [Abstract] |  |  |
Net actuarial loss | 286 | 417 |
Prior service cost | (220) | (440) |
Total before tax effects | 66 | (23) |
Net periodic benefit cost [Abstract] |  |  |
Service cost | 0 | 0 | 0
Interest cost | 9 | 16 | 16
Expected return on plan assets | 0 | 0 | 0
Recognized actuarial loss | 74 | 105 | 123
Recognized prior service benefit due to curtailments | 0 | 0 | 0
Amortization of prior service cost | (220) | (220) | (220)
Net periodic cost (benefit) | (137) | (99) | (81)
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss): [Abstract] |  |  |
Net actuarial (gain) loss | (57) | 31 | 22
Recognized actuarial loss | (74) | (105) | (123)
Prior service credit | 0 | 0 | 0
Amortization of prior service benefit | 220 | 220 | 220
Total before tax effect | 89 | 146 | 119
Total recognized in net (benefit) cost and other comprehensive income (loss) (before tax effect) | $ (48) | $ 47 | $ 38
Average future working lifetime of active participants | 5 years |  |
Weighted-average assumptions for net periodic cost [Abstract] |  |  |
Discount rate | 3.33% | 4.35% | 3.74%
Discount rate | 2.61% | 3.33% | 4.35%
Health care cost trend: Ultimate (Pre-65/Post 65) |  |  | 5.00%
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | $ 0 | $ 0 | $ 0
Estimated benefit payments for each of next five years and aggregate amount expected to be paid [Abstract] |  |  |
2021 | 48 |  |
2022 | 35 |  |
2023 | 36 |  |
2024 | 20 |  |
2025 | 19 |  |
2026-2030 | $ 74 |  |
Health care cost trend: Initial |  |  | 6.50%
Defined Benefit Health Care Plan | Minimum |  |  |
Weighted-average assumptions for net periodic cost [Abstract] |  |  |
Health care cost trend rate assumed, next fiscal year | 6.95% | 6.95% | 6.95%
Health care cost trend: Ultimate (Pre-65/Post 65) | 4.75% | 4.75% | 4.75%
Estimated benefit payments for each of next five years and aggregate amount expected to be paid [Abstract] |  |  |
Health care cost trend: Initial | 6.95% | 6.95% |
Defined Benefit Health Care Plan | Maximum |  |  |
Weighted-average assumptions for net periodic cost [Abstract] |  |  |
Health care cost trend rate assumed, next fiscal year | 5.45% | 5.45% | 5.45%
Health care cost trend: Ultimate (Pre-65/Post 65) | 4.75% | 4.75% | 4.75%
Estimated benefit payments for each of next five years and aggregate amount expected to be paid [Abstract] |  |  |
Health care cost trend: Initial | 5.45% | 5.45% |
Executive Supplemental Pension Plan |  |  |
Amount recognized in accumulated other comprehensive income [Abstract] |  |  |
Net actuarial loss | $ 359 | $ 283 |
Prior service cost | 0 | 0 |
Total before tax effects | 359 | 283 |
Accumulated benefit obligation | 1,300 | 1,200 |
Net periodic benefit cost [Abstract] |  |  |
Service cost | 0 | 0 | $ 0
Interest cost | 39 | 49 | 46
Recognized actuarial loss | 13 | 4 | 7
Net periodic cost (benefit) | 52 | 53 | 53
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss): [Abstract] |  |  |
Net actuarial (gain) loss | 89 | 113 | (47)
Recognized actuarial loss | (13) | (4) | (7)
Total before tax effect | 76 | 109 | (54)
Total recognized in net (benefit) cost and other comprehensive income (loss) (before tax effect) | $ 128 | $ 162 | $ (1)
Unrecognized net gain or loss increase threshold percentage for amortization of obligation (in hundredths) | 10.00% |  |
Weighted-average assumptions for net periodic cost [Abstract] |  |  |
Discount rate | 3.33% | 4.35% | 3.74%
Discount rate | 2.61% | 3.33% | 4.35%
Fair value plan assets by asset class [Abstract] |  |  |
Fair value of plan assets | $ 0 | $ 0 | $ 0
Estimated benefit payments for each of next five years and aggregate amount expected to be paid [Abstract] |  |  |
2021 | 108 |  |
2022 | 106 |  |
2023 | 104 |  |
2024 | 101 |  |
2025 | 97 |  |
2026-2030 | $ 417 |  |

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