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Long-Term Debt (Schedule of Long-term Debt) (Details) $ in Thousands			12 Months Ended
	Jul. 12, 2022	Apr. 29, 2015 USD ($)	Dec. 31, 2025 USD ($) Rate	Dec. 31, 2024 USD ($) Rate	Aug. 01, 2017 USD ($)	Aug. 04, 2014 USD ($)
Related Party Transaction [Line Items]
Weighted average interest rate on all long-term debt | Rate			5.80%	6.40%
Affiliated Entity | Westlake
Related Party Transaction [Line Items]
Long-term debt payable to Westlake			$ 399,674	$ 399,674
OpCo Revolver | Limited Partner | Senior Unsecured Revolving Credit Facility
Related Party Transaction [Line Items]
Long-term debt payable to Westlake			$ 22,619	22,619
Basis spread on variable rate, percent			1.75%
OpCo Revolver | Limited Partner | Senior Unsecured Revolving Credit Facility | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Related Party Transaction [Line Items]
Basis spread on variable rate, percent			0.10%
OpCo Revolver | Limited Partner | Senior Unsecured Revolving Credit Facility | Alternate Base Rate
Related Party Transaction [Line Items]
Basis spread on variable rate, percent			1.00%
OpCo Revolver | Limited Partner | Westlake Chemical OpCo LP | Westlake
Related Party Transaction [Line Items]
Maximum borrowing capacity						$ 600,000
OpCo Revolver | Limited Partner | Westlake Chemical OpCo LP | Westlake | Line of Credit
Related Party Transaction [Line Items]
Basis spread on variable rate, percent	2.00%
MLP Revolver | Westlake
Related Party Transaction [Line Items]
Maximum borrowing capacity		$ 300,000			$ 600,000
MLP Revolver | Limited Partner | Senior Unsecured Revolving Credit Facility
Related Party Transaction [Line Items]
Long-term debt payable to Westlake			$ 377,055	$ 377,055
MLP Revolver | Limited Partner | Senior Unsecured Revolving Credit Facility | Minimum
Related Party Transaction [Line Items]
Basis spread on variable rate, percent			1.75%
MLP Revolver | Limited Partner | Senior Unsecured Revolving Credit Facility | Maximum
Related Party Transaction [Line Items]
Basis spread on variable rate, percent			2.75%
MLP Revolver | Limited Partner | Senior Unsecured Revolving Credit Facility | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Related Party Transaction [Line Items]
Basis spread on variable rate, percent			0.10%
MLP Revolver | Limited Partner | Senior Unsecured Revolving Credit Facility | Alternate Base Rate
Related Party Transaction [Line Items]
Basis spread on variable rate, percent	1.00%		1.00%
MLP Revolver | Limited Partner | Westlake | Line of Credit
Related Party Transaction [Line Items]
Maximum consolidated leverage ratio during one year following acquisitions		5.50
Leverage capital ratio required during other periods		4.50
MLP Revolver | Limited Partner | Westlake Chemical OpCo LP | Westlake | Line of Credit
Related Party Transaction [Line Items]
Basis spread on variable rate, percent	2.00%

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