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EMPLOYEE BENEFIT PLANS - Periodic Benefit Cost and Other Changes (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Other changes in plan assets and benefit obligations recognized in accumulated other comprehensive loss: |  |  |
Total defined benefit pension plan adjustments | $ (9,681) | $ (31,122) | $ 5,069
Defined benefit pension plan |  |  |
Components of net periodic benefit cost: |  |  |
Interest cost | 4,185 | 4,864 | 4,462
Expected return on plan assets | (5,861) | (4,932) | (5,784)
Amortization of prior service cost | 186 | 186 | 186
Amortization of net loss | 4,128 | 3,922 | 3,608
Net periodic benefit cost | 2,638 | 4,040 | 2,472
Other changes in plan assets and benefit obligations recognized in accumulated other comprehensive loss: |  |  |
Net actuarial gain (loss) | (5,522) | (7,350) | (3,326)
Reversal of amortization item: Prior service cost | 186 | 186 | 186
Reversal of amortization item: net actuarial loss | 4,128 | 3,922 | 3,608
Total defined benefit pension plan adjustments | (1,208) | (3,242) | 468
Net periodic benefit cost | (2,638) | (4,040) | $ (2,472)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss | $ (3,846) | $ (7,282) |

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- Definition Represents the sum of the total amount of net periodic benefit cost for defined benefit plans for the period and amounts recognized in other comprehensive income (but not yet recognized in net periodic benefit cost), including the net gain (loss) and net prior service cost (credit) arising during the period. + References No definition available. + Details
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- Definition Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4587-114921 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(3) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 3A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109237824&loc=SL108413299-114919 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920 + Details
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