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Retirement Plans And Postretirement Benefits (Narrative) (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2004
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined Benefit Plan, Option to Remain in Plan, Period |  |  |  | 5 years
Defined benefit plan, accumulated benefit obligation | $ 121,800 | $ 133,100 |  |
Defined Contribution Plan, Employer Discretionary Contribution Amount | 1,600 | 3,000 | $ 3,000 |
Mark-to-market adjustment | $ (700) | (3,000) | 9,600 |
Defined Benefit Plan, maximum salary increase |  |  |  | 6.00%
Scenario, Adjustment |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent | 45.00% |  |  |
Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent | 5.00% |  |  |
Union Carbide | GrafTech International Ltd |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions |  |  |  | 50.00%
Postemployment Retirement Benefit |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Employer contributions | $ 1,400 | 1,300 |  |
Defined Benefit Plan, Benefit Obligation | 12,500 | 14,300 |  |
Net Cost | 500 | 2,000 | (900) |
Mark-to-market adjustment | $ 400 | $ 1,100 | $ 1,600 |

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- Definition Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Amount of gain (loss), recognized immediately as component of net periodic benefit (cost) credit, for change in value of benefit obligation or plan assets from experience different from that assumed, change in actuarial assumption, or consequence of temporarily deviating from substantive plan. Includes, but is not limited to, amount in excess of 10 percent of greater of fair value of plan assets or benefit obligation. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480535/715-20-45-3A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-6 + Details
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