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Related Party Transactions (Cost of Sales from Related Parties) (Details) - Affiliated Entity - Westlake - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Feedstock Purchased
Related Party Transaction [Line Items]
Related Parties Amount in Cost of Sales	$ 382,698	$ 310,856	$ 398,700
Other Service Charges
Related Party Transaction [Line Items]
Related Parties Amount in Cost of Sales	$ 133,824	$ 125,702	$ 123,039

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Amount included in cost of sales related to transactions with related parties incurred and recorded in the statement of operations for the period.

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