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Pension, Savings, and Other Employee Benefits - Schedule Of Components Of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Pension Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Service cost | $ 30 | $ 41 | $ 37
Interest cost | 30,207 | 27,877 | 29,380
Expected return on plan assets | (36,908) | (32,897) | (36,015)
Prior service cost/(credit) | 0 | 0 | 52
Actuarial (gain)/loss | 9,888 | 12,102 | 9,521
Net periodic benefit cost | 3,217 | 7,123 | 2,975
ASC 715 settlement expense | 0 | 0 | 43
Total periodic benefit costs | 3,217 | 7,123 | 3,018
Other Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Service cost | 94 | 133 | 107
Interest cost | 1,413 | 1,309 | 1,305
Expected return on plan assets | (1,136) | (1,074) | (947)
Prior service cost/(credit) | 32 | 0 | 95
Actuarial (gain)/loss | (493) | (387) | (567)
Net periodic benefit cost | (90) | (19) | (7)
ASC 715 settlement expense | 194 | 99 | 0
Total periodic benefit costs | $ 104 | $ 80 | $ (7)

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- Definition Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) 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/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(5) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a)(5) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920 + 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/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 3: 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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