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Related Party Transactions - Narrative (Details) carbon_credit in Thousands, € in Millions, $ in Millions |  |  | 1 Months Ended | 3 Months Ended |  |
--- | --- | --- | --- | --- | --- | ---
Dec. 21, 2023 EUR (€) € / carbonCredit | Sep. 28, 2023 EUR (€) | Mar. 31, 2024 EUR (€) € / carbonCredit | Dec. 31, 2023 EUR (€) carbon_credit € / carbonCredit | Mar. 31, 2024 USD ($) € / carbonCredit | Mar. 31, 2023 USD ($) | Sep. 30, 2023 carbon_credit € / carbonCredit | Dec. 09, 2022 USD ($)
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Revenue | $ |  |  |  |  | $ 489.5 | $ 552.4 |  |
Vlissingen facility agreement | Affiliated Entity | Vlissingen |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Credit facility maximum amount | $ |  |  |  |  |  |  |  | $ 90.0
Stated interest rate, percentage |  |  |  |  |  |  |  | 8.75%
Carbon Credit Sale | Affiliated Entity | Grundartangi |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Carbon credit sold in transaction | carbon_credit |  |  |  |  |  |  | 390 |
Sale price (Euro per carbon credit) |  |  |  |  |  |  | 82.18 |
Aggregate amount | € |  | € 32.1 |  |  |  |  |  |
Carbon Credit Repurchase | Affiliated Entity | Grundartangi |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Sale price (Euro per carbon credit) | 83.72 |  | 87.01 | 85.13 | 87.01 |  |  |
Aggregate amount | € | € 32.7 |  | € 33.9 | € 33.2 |  |  |  |
Second Repurchase Agreement, Carbon Credit Sale | Affiliated Entity | Grundartangi |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Carbon credit sold in transaction | carbon_credit |  |  |  | 40 |  |  |  |
Sale price (Euro per carbon credit) |  |  |  | 69.30 |  |  |  |
Second Repurchase Agreement, Carbon Credit Repurchase | Affiliated Entity | Grundartangi |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Sale price (Euro per carbon credit) |  |  | 72.59 | 70.71 | 72.59 |  |  |
Aggregate amount | € |  |  | € 2.9 | € 2.8 |  |  |  |
Supply Commitment | Glencore |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Revenue | $ |  |  |  |  | $ 35.5 | $ 21.0 |  |
Consolidated sales | Customer concentration risk | Glencore |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Major customer, percentage of revenue, net (percent) |  |  |  |  | 64.30% | 75.00% |  |
Glencore |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Ownership percentage by noncontrolling owners |  |  | 42.90% |  | 42.90% |  |  |
Economic ownership percentage by related party |  |  | 46.00% |  | 46.00% |  |  |

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