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Related Party Transactions (Debt Payable to Related Parties) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023
Related Party Transaction [Line Items] |  |  |
Interest expense—Westlake | $ 22,899 | $ 25,701 | $ 26,501
Accrued interest on related party debt | 6,372 | 933 |
Affiliated Entity |  |  |
Related Party Transaction [Line Items] |  |  |
Accrued interest on related party debt | 5,508 | 5,848 |
Affiliated Entity | Westlake |  |  |
Related Party Transaction [Line Items] |  |  |
Interest expense—Westlake | 22,899 | 25,701 | $ 26,501
Long-term debt payable to Westlake | 399,674 | 399,674 |
Affiliated Entity | Westlake | Accrued Liabilities |  |  |
Related Party Transaction [Line Items] |  |  |
Accrued interest on related party debt | $ 5,508 | $ 5,848 |

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