Related Party Transactions (Major Customer and Concentration Risk) (Details)	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Affiliated Entity \| Westlake \| Revenue Benchmark \| Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk percentage	80.10%	90.60%	83.10%	86.00%

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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 275
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482861/275-10-50-18

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 275
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 275
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Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 275
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Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 275
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-Section 50
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Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Topic 275
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 275
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References + Details