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Long-Term Debt | 12 Months Ended
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Dec. 31, 2025
Debt Disclosure [Abstract] |
Long-Term Debt | Long-Term Debt Long-term debt payable to Westlake consists of the following:
|  | December 31,
|  | 2025 |  | 2024
OpCo Revolver |  | $ | 22,619 |  |  | $ | 22,619 |
MLP Revolver |  | 377,055 |  |  | 377,055 |
Long-term debt payable to Westlake |  | $ | 399,674 |  |  | $ | 399,674 |
On August 4, 2014, OpCo entered into a $600,000 senior unsecured revolving credit facility agreement with Westlake (as subsequently amended, the "OpCo Revolver"). On July 12, 2022, OpCo entered into the Second Amendment (the "OpCo Revolver Amendment") to the OpCo Revolver. Prior to the OpCo Revolver Amendment, the OpCo Revolver bore interest at the London Interbank Offered Rate ("LIBOR") plus 2.0%. The OpCo Revolver Amendment, among other things, extended the maturity date of the OpCo Revolver from September 25, 2023 to July 12, 2027 and provided for the replacement of LIBOR with the Secured Overnight Financing Rate, as administered by the Federal Reserve Bank of New York ("SOFR"). Borrowings under the OpCo Revolver now bear interest at a variable rate of either (a) SOFR plus the Applicable Margin plus a 0.10% credit spread adjustment or, if SOFR is no longer available, (b) the Alternate Base Rate plus the Applicable Margin minus 1.0%. The Applicable Margin under the OpCo Revolver is 1.75%. As of December 31, 2025, outstanding borrowings under the OpCo Revolver bore interest at SOFR plus the Applicable Margin and credit spread adjustment. On April 29, 2015, the Partnership entered into a $300,000 revolving credit facility agreement with an affiliate of Westlake (as subsequently amended, the "MLP Revolver"). In 2017, the Partnership entered into an amendment to the MLP Revolver credit agreement, increasing borrowing capacity from $300,000 to $600,000. On July 12, 2022, the Partnership entered into the Fourth Amendment (the "MLP Revolver Amendment") to the MLP Revolver. Prior to the MLP Revolver Amendment, the MLP Revolver bore interest at a variable rate of either (a) LIBOR plus 2.0% or, if LIBOR were no longer available, (b) the Alternate Base Rate plus 1.0%. The MLP Revolver Amendment, among other things, extended the maturity date of the MLP Revolver from March 19, 2023 to July 12, 2027 and provided for the replacement of LIBOR with SOFR as the reference rate. Borrowings under the MLP Revolver now bear interest at a variable rate of either (a) SOFR plus the Applicable Margin plus a 0.10% credit spread adjustment or, if SOFR is no longer available, (b) the Alternate Base Rate plus the Applicable Margin minus 1.0%. The Applicable Margin under the MLP Revolver varies between 1.75% and 2.75%, depending on the Partnership's Consolidated Leverage Ratio. As of December 31, 2025, outstanding borrowings under the MLP Revolver bore interest at SOFR plus the Applicable Margin and credit spread adjustment. The MLP Revolver provides that the Partnership may pay all or a portion of the interest on any borrowings in kind, in which case any such amounts would be added to the principal amount of the loan. The MLP Revolver requires that the Partnership maintain a consolidated leverage ratio of either (1) during any one-year period following certain types of acquisitions (including acquisitions of additional interests in OpCo), 5.50:1.00 or less, or (2) during any other period, 4.50:1.00 or less. The MLP Revolver also contains certain other customary covenants. The repayment of borrowings under the MLP Revolver is subject to acceleration upon the occurrence of an event of default. As of December 31, 2025, the Partnership was in compliance with all of the covenants under the OpCo Revolver and the MLP Revolver. The weighted average interest rate on all long-term debt was 5.8% and 6.4% at December 31, 2025 and 2024, respectively. As of December 31, 2025, the Partnership had no scheduled maturities of long-term debt until 2027. The OpCo Revolver and the MLP Revolver are scheduled to mature on July 12, 2027.

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