v3.26.3
Segment Reporting (Narrative) (Details)
9 Months Ended
Sep. 30, 2026
segment
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]  
Number of operating segments 1
Number of reportable segments 1
External Customers | Graphite Electrodes | Revenue Benchmark | Customer Concentration Risk  
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]  
Revenues derived from external customers (percent) 89.00%