Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Disaggregation of Revenue [line Items]
Net sales	$ 140,163	$ 143,998	$ 392,626	$ 387,677
Graphite Electrodes
Disaggregation of Revenue [line Items]
Net sales	120,409	132,909	347,546	353,611
By-products and other
Disaggregation of Revenue [line Items]
Net sales	$ 19,754	$ 11,089	$ 45,080	$ 34,066

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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