v3.25.4
Retirement Plans And Postretirement Benefits (Narrative) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2005
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Option to Remain in Plan, Period       5 years
Defined benefit plan, accumulated benefit obligation $ 99,400 $ 121,800    
Defined Contribution Plan, Employer Discretionary Contribution Amount 1,400 1,600 $ 3,000  
Mark-to-market adjustment 2,900 (700) (3,000)  
Defined Benefit Plan, maximum salary increase       6.00%
United States        
Defined Benefit Plan Disclosure [Line Items]        
Voluntary lump sum 24,000      
Employer contributions 1,525 4,385    
Defined Benefit Plan, Benefit Obligation 62,030 89,455 97,322  
Net Cost (328) (730) (661)  
Mark-to-market adjustment 970 1,370 2,513  
Settlement gain $ 820 0 0  
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 $ 1,500 1,400    
Defined Benefit Plan, Benefit Obligation 12,100 12,500    
Net Cost 300 500 2,000  
Mark-to-market adjustment $ 500 $ 400 $ 1,100