0001604665-26-000010 | 10-K | XBRL Viewer | Westlake Chemical Partners LP

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Supplemental Information (Cash Flow Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Related Party Transaction [Line Items]
Capital expenditures incurred but not yet paid	$ 3,243	$ 9,863	$ 7,809
Interest paid	23,237	26,528	24,537
Income taxes paid	873	831	827
Right-of-use assets obtained in exchange for operating lease obligations	920	758	5,079
Reimbursement to Parent for State Tax \| Westlake \| Affiliated Entity
Related Party Transaction [Line Items]
Income taxes paid	333	351	347
State and Local Jurisdiction
Related Party Transaction [Line Items]
Income taxes paid	$ 540	$ 480	$ 480

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483326/850-10-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483326/850-10-50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483326/850-10-50-3

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(k)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(k)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-13

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c)(2)(i))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c)(2)(ii))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(g)(3))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

+ Details

Property, Plant and Equipment (Schedule Of Property, Plant And Equipment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment, Net [Abstract]
Building and improvements	$ 18,774	$ 18,562
Plant and equipment	2,020,193	1,950,479
Other	124,517	118,870
Property, plant and equipment, gross	2,163,484	2,087,911
Less: Accumulated depreciation	(1,293,700)	(1,237,929)
Property, plant and equipment, net, before construction in progress	869,784	849,982
Construction in progress	16,228	53,606
Property, plant and equipment, net	886,012	903,588
Depreciation expense	$ 87,018	$ 86,253	$ 84,511

Agreements with Westlake and Related Parties	12 Months Ended
Agreements with Westlake and Related Parties	Dec. 31, 2025
Equity [Abstract]
Agreements with Westlake and Related Parties	Agreements with Westlake and Related Parties Ethylene Sales Agreement OpCo is party to an ethylene sales agreement with Westlake (the "Ethylene Sales Agreement"), which requires Westlake to purchase a minimum volume of ethylene each year equal to 95% of OpCo's planned ethylene production per year (the "Minimum Commitment"), subject to certain exceptions and a maximum commitment of 3.8 billion pounds per year. So long as Westlake is not in default under the Ethylene Sales Agreement, if OpCo's actual production exceeds planned production, Westlake has the option to purchase up to 95% of the excess production (the "Excess Production Option"). The fee for each pound of ethylene purchased by Westlake from OpCo up to the Minimum Commitment in any calendar year will equal: •the actual price OpCo pays Westlake to purchase ethane (or other feedstock, such as propane, if applicable) to produce each pound of ethylene, subject to a specified cap and a floor on the amount of feedstock that should be needed to produce each pound of ethylene; plus •the actual price OpCo pays Westlake to purchase natural gas to produce each pound of ethylene, subject to a specified cap and a floor on the amount of natural gas that should be needed to produce each pound of ethylene; plus •OpCo's estimated operating costs (including selling, general and administrative expenses), divided by OpCo's planned ethylene production for the year (in pounds); plus •a five-year average of OpCo's expected future maintenance capital expenditures and other turnaround expenditures, divided by OpCo's planned ethylene production capacity for the year (in pounds); less •the proceeds (on a per pound of ethylene basis) received by OpCo from the sale of co-products (including, but not limited to, propylene, crude butadiene, pyrolysis gasoline and hydrogen) associated with producing the ethylene purchased by Westlake; plus •a $0.10 per pound margin. The fee for the Excess Production Option, if exercised, equals OpCo's estimated variable operating costs of producing the incremental ethylene, net of revenues from co-products sales plus a $0.10 per pound margin. The estimated operating costs and the expected future maintenance capital expenditures and other turnaround expenditures will be adjusted at the end of each year, to be applicable for the fee for the next calendar year, to reflect certain changes in forecasted costs. Under the Ethylene Sales Agreement OpCo has the option to curtail up to approximately 5% of its ethylene production annually in the event OpCo reasonably determines that its sales of such ethylene to third parties during the relevant period would be uneconomic. Certain of the pricing components that make up the price for ethylene sold under the Ethylene Sales Agreement are modified to reflect the portion of OpCo's production capacity that is used to process Westlake's purge gas instead of producing ethylene. Costs specific to the processing of Westlake's purge gas are recovered under the Services and Secondment Agreement (as described below), and not the Ethylene Sales Agreement. Pursuant to the Ethylene Sales Agreement, Westlake is obligated to pay for the annual minimum quantity (95% of OpCo's budgeted ethylene production), which is measured on an annual basis. In the event Westlake purchases less than its annual commitment, the Partnership recognizes a buyer deficiency fee ("Buyer Deficiency Fee") representing fixed margin and all expenses and expenditures incurred per pound of volume committed but not taken by Westlake. The annual commitment is not reduced for a force majeure event affecting OpCo's plants that lasts fewer than 45 consecutive days; however, in the event of such a force majeure event, the Partnership recognizes a Buyer Deficiency Fee representing fixed margin and unavoided operating and maintenance capital expenditures and maintenance expenses per pound of volume committed by Westlake during the force majeure period. Payment of the Buyer Deficiency Fee is scheduled to be received by the Partnership after the conclusion of the year in which the annual commitment was not purchased and taken by Westlake. The result of the fee structure is that OpCo should generally recover the portion of its total operating costs and maintenance capital expenditures and other turnaround expenditures corresponding to the portion of OpCo's aggregate production that is purchased by Westlake. Any shortfall in recovery of such costs is generally recognized during the period in which the related operating, maintenance or turnaround activities occur and is recoverable from Westlake in the subsequent year. Under the Ethylene Sales Agreement, if production costs billed to Westlake on an annual basis are less than 95% of the actual production costs incurred by OpCo during the contract year, OpCo is entitled to recover the shortfall in such production costs (proportionate to the volume sold to Westlake) in the subsequent year ("Shortfall"). The Ethylene Sales Agreement provides that, if compliance with any law adopted or modified following the IPO results in OpCo incurring additional costs in excess of $500 in any contract year, OpCo is entitled to charge Westlake a monthly surcharge following efforts to mitigate the effects of such matter. On October 28, 2025, OpCo and Westlake agreed to renew the Ethylene Sales Agreement through December 31, 2027 in accordance with its terms, which provide for an initial term through December 31, 2026 and automatic 12-month renewal periods until terminated at the end of the initial term or any renewal term of not less than 12-months' notice. Feedstock Supply Agreement OpCo is party to a feedstock supply agreement with Westlake, pursuant to which Westlake sells to OpCo ethane and other feedstock in amounts sufficient for OpCo to produce the ethylene to be sold under the Ethylene Sales Agreement (the "Feedstock Supply Agreement"). The Feedstock Supply Agreement provides that OpCo may obtain feedstock from Westlake based on Westlake's total cost of purchasing and delivering the feedstock, including applicable transportation, storage and other costs. Title and risk of loss for all feedstock purchased by OpCo through the Feedstock Supply Agreement passes to OpCo upon delivery to one of three delivery points described in the Feedstock Supply Agreement. The Feedstock Supply Agreement has an initial term extending until December 31, 2026 and automatically renews thereafter for successive 12-month terms unless terminated by either party; provided, however, that such agreement can only be renewed in the event the Ethylene Sales Agreement is renewed simultaneously. The Feedstock Supply Agreement may, in certain circumstances, terminate concurrently with the termination of the Ethylene Sales Agreement. On October 28, 2025, OpCo and Westlake agreed to renew the Feedstock Supply Agreement through December 31, 2027 in accordance with its terms, which provide for an initial term through December 31, 2026 and automatic 12-month renewal periods until terminated at the end of the initial term or any renewal term on not less than 12-months' notice. Services and Secondment Agreement OpCo is party to a Services and Secondment Agreement with Westlake, pursuant to which OpCo provides Westlake with certain services required for the operation of Westlake's facilities; and Westlake provides OpCo with comprehensive operating services for OpCo's facilities, ranging from services relating to the maintenance and operations of the common facilities necessary for the operation of OpCo's units, to making available certain shared utilities such as electricity and natural gas that are necessary for the operation of OpCo's units. Westlake also seconds employees to OpCo to allow OpCo to operate its facilities. Such seconded employees are under the control of OpCo while they work on OpCo's facilities. In connection with the renewals of the Ethylene Sales Agreement and the Feedstock Supply Agreement, on October 28, 2025, OpCo and certain affiliates of Westlake entered into an amendment to the Services and Secondment Agreement to align the date of expiration of such agreement with the date of expiration term of the Ethylene Sales Agreement. Westlake and OpCo each can terminate the Services and Secondment Agreement under certain circumstances, including if the other party materially defaults on the performance of its obligations and such default continues for a 30-day period. Site Lease Agreements OpCo has entered into two site lease agreements with Westlake pursuant to which Westlake leases to OpCo the real property underlying Lake Charles Olefins and Calvert City Olefins and grants OpCo rights to access and use certain other portions of Westlake's ethylene production facilities that are necessary to operate OpCo's production facilities. OpCo owes Westlake one dollar per site per year. The site lease agreements each have a term of 50 years. Each of the site lease agreements may be renewed if agreed by the parties. Omnibus Agreement The Partnership has entered into an Omnibus Agreement with Westlake that addresses (1) Westlake's indemnification of the Partnership for certain matters, including environmental and tax matters, (2) the provision by Westlake of certain management and other general and administrative services to the Partnership and its general partner and (3) the Partnership's reimbursement to Westlake for such services. The Omnibus Agreement also addresses Westlake's right of first refusal on any proposed transfer of the ethylene production facilities that serve Westlake's other facilities and Westlake's right of first refusal on any proposed transfer of the Partnership's equity interests in OpCo. In connection with the renewals of the Ethylene Sales Agreement and the Feedstock Supply Agreement, on October 28, 2025, the Partnership, OpCo and certain affiliates of Westlake also entered into an amendment to the Omnibus Agreement to provide that the Omnibus Agreement would terminate upon termination of the Ethylene Sales Agreement. Exchange Agreement OpCo and Westlake are parties to an exchange agreement, which continues on an annual basis, unless and until terminated by either party. Under the exchange agreement, OpCo may require Westlake to deliver up to 200 million pounds of ethylene for OpCo per year from the Site Leases to an ethylene hub in Mt. Belvieu, Texas, for which OpCo would be required to pay an exchange fee of $0.006 per pound. OpCo Partnership Agreement The Partnership, OpCo GP and Westlake are parties to an agreement of limited partnership for OpCo (the "OpCo LP Agreement"). The OpCo LP Agreement governs the ownership and management of OpCo and designates OpCo GP as the general partner of OpCo. OpCo GP generally has complete authority to manage OpCo's business and affairs. The Partnership controls OpCo GP, as its sole member, subject to certain approval rights held by Westlake. Investment Management Agreement The Partnership, OpCo and Westlake are parties to an Investment Management Agreement that authorizes Westlake to invest the Partnership and OpCo's excess cash with Westlake for durations of up to a maximum of nine months. Per the terms of the Investment Management Agreement, the Partnership earns a market return plus five basis points and Westlake provides daily availability of the invested cash to meet any liquidity needs of the Partnership or OpCo. The Partnership had $23,378 of invested cash under the Investment Management Agreement at December 31, 2025.

Description of Business and Significant Accounting Policies

12 Months Ended

Dec. 31, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Description of Business and Significant Accounting Policies

Description of Business

Westlake Chemical Partners LP (the "Partnership") is a Delaware limited partnership formed in March 2014 to operate, acquire and develop ethylene production facilities and related assets. On August 4, 2014, the Partnership completed its initial public offering of 12,937,500 common units representing limited partner interests.

The Partnership owns 22.8% limited partner interest in Westlake Chemical OpCo LP ("OpCo") and a 100% interest in Westlake Chemical OpCo GP LLC ("OpCo GP"), which is the general partner of OpCo. OpCo owns three ethylene production facilities and one common carrier ethylene pipeline (collectively, the "Contributed Assets"). The remaining 77.2% limited partner interest in OpCo is owned by Westlake Corporation. References to "Westlake" refer collectively to Westlake Corporation and its subsidiaries, other than the Partnership, OpCo and OpCo GP.

OpCo and Westlake entered into an ethylene sales agreement (the "Ethylene Sales Agreement") pursuant to which the Partnership generates a substantial majority of its revenue. For more information, see Note 2.

Basis of Presentation

The accompanying consolidated financial statements have been prepared in conformity with the accounting principles generally accepted in the United States.

The Partnership holds a 22.8% limited partner interest and the entire non-economic general partner interest in OpCo. The remaining 77.2% limited partner interest in OpCo is owned directly by Westlake, which has no rights to direct the activities that most significantly impact the economic performance of OpCo. As a result of the fact that substantially all of OpCo's activities are conducted on behalf of Westlake, and the fact that OpCo exhibits disproportionality of voting rights to economic interest, OpCo was deemed to be a variable interest entity. The Partnership, through its ownership of OpCo's general partner, has the power to direct the activities that most significantly impact the economic performance of OpCo, and it also has the obligation or right to absorb losses or receive benefits from OpCo that could potentially be significant to OpCo. As such, the Partnership was determined to be OpCo's primary beneficiary and therefore consolidates OpCo's results of operations and financial position. The Partnership's operations consist exclusively of the variable interest entity's operations and, as such, no additional variable interest entity disclosures are considered necessary. Westlake's retained interest of 77.2% is recorded as noncontrolling interest in the Partnership's consolidated financial statements.

Cash and Cash Equivalents

Cash equivalents consist of highly liquid investments that are readily convertible into cash and have a maturity of three months or less at the date of acquisition.

Allowance for Credit Losses

The determination of the allowance for credit losses is based on estimation of the amount of accounts receivable that the Partnership believes are unlikely to be collected. Estimating this amount requires analysis of the financial strength of the Partnership's customers, the use of historical experience, the Partnership's accounts receivable aged trial balance, customer specific collectability analysis and an evaluation of economic conditions. The allowance for credit losses is reviewed quarterly. Past due balances over 90 days and high risk accounts, as determined by the analysis of financial strength of customers, are reviewed individually for collectability.

Inventories

Inventories primarily include product, material and supplies. Inventories are stated at the lower of cost or net realizable value. Cost is determined using the first-in, first-out ("FIFO") or average method.

Property, Plant and Equipment

Property, plant and equipment are carried at cost, net of accumulated depreciation. Cost includes expenditures for improvements and betterments that extend the useful lives of the assets and interest capitalized on significant capital projects.

Interest expense is capitalized for qualifying assets under construction. Capitalized interest costs are included in property, plant and equipment and are depreciated over the useful life of the related asset. Capitalized interest was $79, $197 and $164 for the years ended December 31, 2025, 2024 and 2023, respectively. Repair and maintenance costs are charged to operations as incurred. Gains and losses on the disposal or retirement of property, plant and equipment are reflected in the statement of operations when the assets are sold or retired.

The accounting guidance for asset retirement obligations requires the recording of liabilities equal to the fair value of asset retirement obligations and corresponding additional asset costs, when there is a legal asset retirement obligation as a result of existing or enacted law, statute or contract. The Partnership has conditional asset retirement obligations for the removal and disposal of hazardous materials from certain of the Partnership's manufacturing facilities. However, no asset retirement obligations have been recognized because the fair value of the conditional legal obligation cannot be measured due to the indeterminate settlement date of the obligation.

Depreciation is provided by utilizing the straight-line method over the estimated useful lives of the assets as follows:


Classification									Years
Buildings and improvements									40
Plant and equipment									25
Ethylene pipeline									35
Other									3-15

Impairment of Long-Lived Assets

The accounting guidance for the impairment or disposal of long-lived assets requires that the Partnership assess long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable, including when negative conditions such as significant current or projected operating losses exist. Other factors considered by the Partnership when determining if an impairment assessment is necessary include, but are not limited to, significant changes or projected changes in supply and demand fundamentals (which would have a negative impact on operating rates or margins), new technological developments, new competitors with significant raw material or other cost advantages, adverse changes associated with the United States and world economies and uncertainties associated with governmental actions. Long-lived assets assessed for impairment are grouped by asset group, the lowest level for which identifiable cash flows are largely independent of the cash flows of other groups of assets and liabilities. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future net undiscounted cash flows expected to be generated by the asset group. Assets are considered to be impaired if the carrying amount of an asset exceeds the future undiscounted cash flows. The impairment recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or estimated fair value less costs to sell.

Impairment of Goodwill

The accounting guidance requires that goodwill be tested for impairment at least annually, or when events or changes in circumstances indicate the fair value of a reporting unit with goodwill has been reduced below its carrying amount. The impairment test for the recorded goodwill was performed in the fourth quarter of 2025 and did not indicate impairment of the goodwill. As of December 31, 2025, the Partnership's recorded goodwill was $5,814. See Note 6 for more information on the Partnership's annual goodwill impairment test.

Turnaround Costs

The Partnership accounts for turnaround costs under the deferral method. Turnarounds are the scheduled and required shutdowns of specific operating units in order to perform planned major maintenance activities. The costs related to the significant overhaul and refurbishment activities include maintenance materials, parts and direct labor costs. The costs of the turnaround are deferred when incurred at the time of the turnaround and amortized (within depreciation and amortization) on a straight-line basis until the next planned turnaround, which typically ranges from five to eight years. Deferred turnaround costs are presented as a component of deferred charges and other assets, net. The cash outflows related to these costs are included in operating activities in the consolidated statement of cash flows.

Concentration of Credit Risk

Financial instruments which potentially subject the Partnership to concentration of risk consist principally of trade receivables from third-party customers who purchase ethylene and ethylene co-products. The Partnership performs periodic credit evaluations, as applicable, of the customers' financial condition and generally does not require collateral. The Partnership maintains allowances for potential losses, as applicable.

Revenue Recognition

Revenue is recognized when OpCo transfers control of inventories to customers. Amounts recognized as revenues reflect the consideration to which OpCo expects to be entitled in exchange for those inventories. The Partnership and OpCo incorporate production volume and production cost forecasts in the estimated transaction prices from sales to Westlake under the Ethylene Sales Agreement.

The Partnership recognizes revenue and accounts receivable upon transferring control of inventories to its customers. Ethylene sold to Westlake under the Ethylene Sales Agreement is transferred to Westlake immediately after production and recognized in sales. Control of inventories sold to third parties generally transfers upon shipment to the customer. The Partnership excludes taxes collected on behalf of customers from the estimated contract price. Provisions for discounts, rebates and returns are incorporated in the estimate of variable consideration and reflected as reduction to revenue in the same period as the related sales.

The Partnership does not disclose the value of unsatisfied performance obligations because its contracts with customers (1) have an original expected duration of one year or less or (2) have only variable consideration that is calculated based on market prices at a specified date and is allocated to wholly unsatisfied performance obligations.

The Partnership generates a substantial majority of its revenue from sales to Westlake under the Ethylene Sales Agreement. The Ethylene Sales Agreement is intended to generate a long-term, fixed cash margin per pound. See Note 2 for a description of the terms of the Ethylene Sales Agreement. The Partnership's direct commodity price risk is limited to the sales to third parties. See the Partnership's consolidated statements of operations for the disaggregation of net sales to Westlake and net sales to third parties.

Transportation and Freight

Amounts billed to customers for freight and handling costs on outbound shipments are included in net sales in the consolidated statements of operations. Transportation and freight costs incurred by the Partnership on outbound shipments are included in cost of sales in the consolidated statements of operations.

Environmental Costs

Environmental costs relating to current operations are expensed or capitalized, as appropriate, depending on whether such costs provide future economic benefits. Remediation liabilities are recognized when the costs are considered probable and can be reasonably estimated. Measurement of liabilities is based on currently enacted laws and regulations, existing technology and undiscounted site-specific costs. Environmental liabilities in connection with properties that are sold or closed are realized upon such sale or closure, to the extent they are probable and estimable and not previously reserved. Recognition of any joint and several liabilities is based upon the Partnership's best estimate of its final pro rata share of the liability.

Income Taxes

The Partnership is a limited partnership and is treated as a partnership for U.S. federal income tax purposes and, therefore, is not liable for entity-level federal income taxes. The Partnership is, however, subject to state and local income taxes. Deferred tax expense or benefit is the result of changes in the deferred tax assets and liabilities during the period. Valuation allowances are recorded against deferred tax assets when it is considered more likely than not that the deferred tax assets will not be realized on a separate tax return basis.

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.

Other Comprehensive Income

The Partnership has not reported consolidated statements of comprehensive income for the years ended December 31, 2025, 2024 and 2023 due to immateriality of the components of other comprehensive income.

Recently Issued Accounting Pronouncements

Measurement of Credit Losses for Accounts Receivable and Contract Assets (ASU No. 2025-05)

In July 2025, the Financial Accounting Standards Board ("FASB") issued an accounting standards update to add a practical expedient in developing reasonable and supportable forecasts as part of estimating expected credit losses. All entities may elect a practical expedient that assumes the current conditions as of the balance sheet date do not change for the remaining life of the asset. The amendments in this update are effective for annual reporting periods beginning after December 15, 2025 and interim reporting periods within those annual reporting periods, with early adoption permitted. Entities should apply the new guidance prospectively. The Partnership does not expect that this accounting standard, upon adoption, will have a material impact on the Partnership's consolidated financial statements.

Disaggregation of Income Statement Expenses (ASU No. 2024-03)

In November 2024, the FASB issued an accounting standards update requiring public entities to disclose, on an annual and interim basis, detailed information about the types of expenses in relevant expense captions presented on the face of the income statement, including amounts for inventory purchases, employee compensation, depreciation and amortization of intangible assets and a qualitative description for remaining amounts not separately disaggregated. Additionally, the update requires disclosure of total selling expenses, and in annual periods, an entity's definition of selling expenses. The amendments in this update are effective for annual reporting periods beginning after December 15, 2026, and interim periods beginning after December 15, 2027 and are to be applied either prospectively or retrospectively. Early adoption is permitted. The Partnership is currently evaluating the impact of the update on the disclosures in the Partnership's consolidated financial statements.

Recently Adopted Accounting Standard

Income Taxes (ASU No. 2023-09)

Related Party Transactions (Related Party Leases) (Details)	12 Months Ended
	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Aug. 04, 2014
Westlake \| Affiliated Entity
Related Party Transaction [Line Items]
Operating lease expense	$ 1,705,000	$ 1,843,000	$ 1,869,000
Westlake Chemical OpCo LP \| Westlake \| Investee \| Site Lease Agreement
Related Party Transaction [Line Items]
Site lease agreement, number	2
Term of operating lease				50 years
Site lease expense	$ 1

Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Property, plant and equipment	$ (1,199)	$ (1,323)
Turnaround costs	(347)	(223)
Total deferred tax liabilities	(1,546)	(1,546)
Noncurrent deferred tax liability	$ (1,546)	$ (1,546)

Goodwill (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Gross	$ 5,814	$ 5,814

Deferred Charges and Other Assets

12 Months Ended

Dec. 31, 2025

Other Assets [Abstract]

Deferred Charges and Other Assets

Deferred charges and other assets, net consist of the following:


	December 31,
	2025		2024
Turnaround costs, net	$	213,953	$	129,565
Other	7,248		8,063
Deferred charges and other assets, net	$	221,201	$	137,628

Amortization expense on deferred charges and other assets of $40,960, $25,646 and $25,692 is included in cost of sales in the consolidated statements of operations for the years ended December 31, 2025, 2024 and 2023, respectively. Certain other assets are amortized over periods ranging from three to twenty years using the straight-line method.

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Dec. 31, 2025
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Accounts Receivable—Third Parties (Tables)

12 Months Ended

Dec. 31, 2025

Accounts Receivable, after Allowance for Credit Loss [Abstract]

Schedule Of Accounts Receivable

Accounts receivable—third parties consist of the following:


	December 31,
	2025		2024
Trade customers	$	9,283	$	11,757
Allowance for credit losses	(170)		(181)

Accounts receivable, net—third parties	$	9,113	$	11,576

Description of Business and Significant Accounting Policies (Schedule Of Estimated Useful Lives Of Assets) (Details)	Dec. 31, 2025
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	40 years
Plant and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	25 years
Ethylene pipeline
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	35 years
Other \| Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	3 years
Other \| Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	15 years

Distributions and Net Income Per Limited Partner Unit (Tables)

12 Months Ended

Dec. 31, 2025

Earnings Per Share [Abstract]

Schedule of Distributions

Distributions are declared subsequent to quarter end; therefore, the table below represents total cash distributions declared from earnings of the related periods pertaining to such distributions.


	Year Ended December 31,
		2025		2024		2023
Net income attributable to the Partnership		$	48,698	$	62,392	$	54,283
Less:
Limited partners' distribution declared on common units		66,453		66,437		66,421


Distribution in excess of net income		$	(17,755)	$	(4,045)	$	(12,138)

Schedule of Earnings Per Share, Basic and Diluted


	Year Ended December 31, 2025
	Limited Partners' Common Units		Incentive Distribution Rights		Total
Net income attributable to the Partnership:
Distribution	$	66,453	$	—	$	66,453
Distribution in excess of net income	(17,755)		—		(17,755)
Net income	$	48,698	$	—	$	48,698
Weighted average units outstanding:
Basic and diluted	35,241,505				35,241,505
Net income per limited partner unit:
Basic and diluted	$	1.38


	Year Ended December 31, 2024
	Limited Partners' Common Units		Incentive Distribution Rights		Total
Net income attributable to the Partnership:
Distribution	$	66,437	$	—	$	66,437
Distribution in excess of net income	(4,045)		—		(4,045)
Net income	$	62,392	$	—	$	62,392
Weighted average units outstanding:
Basic and diluted	35,232,870				35,232,870
Net income per limited partner unit:
Basic and diluted	$	1.77


	Year Ended December 31, 2023
	Limited Partners' Common Units		Incentive Distribution Rights		Total
Net income attributable to the Partnership:
Distribution	$	66,421	$	—	$	66,421
Distribution in excess of net income	(12,138)		—		(12,138)
Net income	$	54,283	$	—	$	54,283
Weighted average units outstanding:
Basic and diluted	35,224,340				35,224,340
Net income per limited partner unit:
Basic and diluted	$	1.54

Distributions Made to Limited Partner, by Distribution

The amended Partnership Agreement provides that the Partnership will distribute cash that is deemed to be an appropriate portion of the Partnership's total operating surplus. If cash distributions to the Partnership's unitholders exceed $1.2938 per common unit in any quarter, the Partnership's unitholders and Westlake, as the holder of the Partnership's incentive distribution rights, will receive distributions according to the following percentage allocations:


	Marginal Percentage Interest in Distributions
Total Quarterly Distribution Per Unit	Unitholders		IDR Holders
Above $1.2938 up to $1.4063	85.0	%	15.0	%
Above $1.4063 up to $1.6875	75.0	%	25.0	%
Above $1.6875	50.0	%	50.0	%

The Partnership's distribution for each quarter in the year ended December 31, 2025 did not exceed the $1.2938 per unit threshold, and, as a result, no distribution was made with respect to the Partnership's incentive distribution rights to Westlake, as the holder of the Partnership's incentive distribution rights.

Distribution Per Common Unit

Distributions per common unit for the years ended December 31, 2025, 2024 and 2023 were as follows:


	Year Ended December 31,
	2025		2024		2023
Distributions per common unit	$	1.8856	$	1.8856	$	1.8856

Supplemental Information (Tables)

12 Months Ended

Dec. 31, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Cash Flow, Supplemental Disclosures

The Partnership's payment of income taxes by jurisdiction is as follows:


	Year Ended December 31,
	2025
Kentucky	$	540
Texas	333
Total income taxes paid	$	873

Unit-based Compensation (Tables)

12 Months Ended

Dec. 31, 2025

Share-Based Payment Arrangement [Abstract]

Schedule of Nonvested Restricted Stock Units Activity

Non-vested phantom unit awards as of December 31, 2025 and 2024 and changes during the period were as follows:


	Number of Units	Weighted Average Fair Value



Non-vested balance at December 31, 2024	14,646	$	23.14
Granted	15,015	21.92
Vested	(14,646)	21.96
Non-vested balance at December 31, 2025	15,015	$	19.00

Related Party Transactions (Tables)

12 Months Ended

Dec. 31, 2025

Schedule of Related Party Transactions

OpCo sells a significant portion of its ethylene production to Westlake. Sales to related parties were as follows:


	Year Ended December 31,
	2025		2024		2023
Net sales—Westlake	$	1,033,276	$	950,801	$	1,026,655

A significant portion of the Partnership's inputs included in cost of sales are supplied by Westlake. Charges from related parties for significant inputs included in cost of sales were as follows:


	Year Ended December 31,
	2025		2024		2023
Feedstock purchased from Westlake and included in cost of sales	$	382,698	$	310,856	$	398,700
Other charges from Westlake and included in cost of sales	133,824		125,702		123,039

Charges from related parties included within selling, general and administrative expenses were as follows:


	Year Ended December 31,
	2025		2024		2023
Services received from Westlake and included in selling, general and administrative expenses	$	25,017	$	25,654	$	27,085

Charges from related parties for goods and services capitalized as assets were as follows:


	Year Ended December 31,
	2025		2024		2023
Goods and services purchased from Westlake and capitalized as assets	$	7,311	$	2,295	$	3,660

The Partnership's receivable under the Investment Management Agreement was as follows:


	December 31,
	2025		2024
Receivable under the Investment Management Agreement	$	23,378	$	134,557

The Partnership's accounts receivable from Westlake were as follows:


	December 31,
	2025		2024
Accounts receivable—Westlake	$	63,571	$	31,975

The Partnership's accounts payable to Westlake were as follows:


	December 31,
	2025		2024
Accounts payable—Westlake	$	19,132	$	20,744

Debt payable to related parties was as follows:


	December 31,
	2025		2024
Long-term debt payable to Westlake	$	399,674	$	399,674

Accounts Receivable—Third Parties

12 Months Ended

Dec. 31, 2025

Accounts Receivable, after Allowance for Credit Loss [Abstract]

Accounts Receivable—Third Parties

Accounts receivable—third parties consist of the following:


	December 31,
	2025		2024
Trade customers	$	9,283	$	11,757
Allowance for credit losses	(170)		(181)

Accounts receivable, net—third parties	$	9,113	$	11,576

Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2025

Property, Plant and Equipment, Net [Abstract]

Schedule Of Property, Plant And Equipment

Property, plant and equipment consist of the following:


	December 31,
	2025		2024

Building and improvements	$	18,774	$	18,562
Plant and equipment	2,020,193		1,950,479
Other	124,517		118,870
	2,163,484		2,087,911
Less: Accumulated depreciation	(1,293,700)		(1,237,929)
	869,784		849,982
Construction in progress	16,228		53,606
Property, plant and equipment, net	$	886,012	$	903,588

Segment Information (Tables)

12 Months Ended

Dec. 31, 2025

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment


	Year Ended December 31,
	2025		2024		2023
Significant segment expenses and other segment items
OpCo
Raw material, energy, manufacturing and logistics costs	$	690,869	$	605,058	$	693,129
Depreciation and amortization	127,978		111,899		110,203
Total cost of sales	818,847		716,957		803,332
Selling, general and administrative expenses	24,853		24,699		26,217
Other segment items (1)	(582)		(3,005)		(1,786)

Interest expense—Westlake
OpCo	$	1,316	$	1,410	$	1,496
Corporate	21,583		24,291		25,005
	$	22,899	$	25,701	$	26,501

Net income
OpCo	$	323,577	$	397,245	$	363,028

A reconciliation of total segment net income to consolidated net income is as follows:


	Year Ended December 31,
	2025		2024		2023
Net income from OpCo	$	323,577	$	397,245	$	363,028
Corporate net loss	(25,001)		(28,086)		(28,402)
Net income	$	298,576	$	369,159	$	334,626


	December 31,
	2025		2024
Total assets
OpCo	$	1,222,123	$	1,238,420
Corporate	34,410		49,536
	$	1,256,533	$	1,287,956

_____________________________

(1)Other segment items includes interest expense—Westlake, other income, net and provision for income taxes.

Inventories (Schedule Of Inventory) (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Inventory, Net [Abstract]
Finished products	$ 2,336	$ 3,748
Feedstock, additives and chemicals	433	310
Inventories	$ 2,769	$ 4,058

Description of Business and Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule Of Estimated Useful Lives Of Assets

Depreciation is provided by utilizing the straight-line method over the estimated useful lives of the assets as follows:


Classification									Years
Buildings and improvements									40
Plant and equipment									25
Ethylene pipeline									35
Other									3-15

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

- Definition

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.

+ References

+ Details

Unit-based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Jul. 15, 2014
Weighted Average Fair Value
Unrecognized compensation weighted average remaining term	7 months 6 days
Phantom Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of phantom units vested	$ 322	$ 423	$ 278
Number of Units
Beginning balance	14,646
Granted (in shares)	15,015
Vested (in shares)	(14,646)
Ending balance	15,015	14,646
Weighted Average Fair Value
Weighted Average Fair Value, beginning balance (usd per share)	$ 23.14
Weighted Average Grant Date Fair Value, Granted (usd per share)	21.92
Weighted Average Grant Date Fair Value, Vested (usd per share)	21.96
Weighted Average Fair Value, ending balance (usd per share)	$ 19.00	$ 23.14
Westlake Chemical Partners LP Long-Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units authorized				1,270,000
Weighted Average Fair Value
Total units available for grant	1,184,657
Unrecognized compensation cost	$ 169
Westlake Chemical Partners LP Long-Term Incentive Plan \| Selling, General and Administrative Expenses
Weighted Average Fair Value
Total compensation cost	$ 301	$ 373	$ 349

Segment Information

12 Months Ended

Dec. 31, 2025

Segment Reporting [Abstract]

Segment Information

The Partnership has one operating segment, which is the Partnership's reportable segment, OpCo. The operating results of the segment are reviewed by the Partnership's Chief Executive Officer, the chief operating decision maker ("CODM"). The CODM evaluates segment performance based on net income. The CODM reviews the OpCo segment's actual net income trends to allocate resources and assess performance.

The OpCo segment's operations consist of two ethylene production facilities in Lake Charles, Louisiana, one ethylene production facility in Calvert City, Kentucky and a 200-mile common carrier ethylene pipeline that runs from Mont Belvieu, Texas to Longview, Texas. OpCo derives substantially all of its revenue from these production facilities primarily by selling ethylene to Westlake and others, as well as through the sale of co-products of ethylene production, including propylene, crude butadiene, pyrolysis gasoline and hydrogen. All of the OpCo segment's operations are located and conducted in the United States. All of the OpCo segment's sales are attributed to the United States.

Sales to Westlake accounted for more than 10% of sales in the OpCo segment, totaling $1,033,276, $950,801 and $1,026,655 for the years ended December 31, 2025, 2024 and 2023, respectively. Consolidated net sales and provision for income taxes as disclosed in the consolidated statements of operations and depreciation and amortization and additions to property, plant and equipment as disclosed in the consolidated statements of cash flows are fully attributed to the OpCo segment, and as such, separate OpCo segment amounts are not repeated in the tables below.

The accounting policies of the OpCo segment are the same as those described in Note 1.


	Year Ended December 31,
	2025		2024		2023
Significant segment expenses and other segment items
OpCo
Raw material, energy, manufacturing and logistics costs	$	690,869	$	605,058	$	693,129
Depreciation and amortization	127,978		111,899		110,203
Total cost of sales	818,847		716,957		803,332
Selling, general and administrative expenses	24,853		24,699		26,217
Other segment items (1)	(582)		(3,005)		(1,786)

Interest expense—Westlake
OpCo	$	1,316	$	1,410	$	1,496
Corporate	21,583		24,291		25,005
	$	22,899	$	25,701	$	26,501

Net income
OpCo	$	323,577	$	397,245	$	363,028

A reconciliation of total segment net income to consolidated net income is as follows:


	Year Ended December 31,
	2025		2024		2023
Net income from OpCo	$	323,577	$	397,245	$	363,028
Corporate net loss	(25,001)		(28,086)		(28,402)
Net income	$	298,576	$	369,159	$	334,626


	December 31,
	2025		2024
Total assets
OpCo	$	1,222,123	$	1,238,420
Corporate	34,410		49,536
	$	1,256,533	$	1,287,956

_____________________________

(1)Other segment items includes interest expense—Westlake, other income, net and provision for income taxes.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Section 50
-Paragraph 21
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2025

Income Tax Disclosure [Abstract]

Schedule Of The Provision For (Benefit From) Income Taxes

The components of income tax of the Partnership are as follows:


	Year Ended December 31,
	2025		2024		2023
Current

State and local	$	548	$	921	$	837

Deferred

State and local	(1)		(86)		(24)

Total provision	$	547	$	835	$	813

Reconciliation Of Taxes Computed At The Statutory Rate To Income Tax Expense

The reconciliation of income tax expense at the U.S. statutory rate to the income tax expense is as follows:


	Year Ended December 31,
	2025
	Amount		Percentage
Provision for federal income tax, at statutory rate	$	62,816	21.0	%
State income tax provision, net of federal income tax effect (1)	547		0.2	%
Partnership income not subject to entity-level federal income tax	(62,816)		(21.0)	%
Total provision	$	547	0.2	%

____________________________

(1) State income taxes in Kentucky and Texas made up the majority (greater than 50 percent) of the tax effect in this category.

Schedule Of Deferred Tax Assets And Liabilities

The tax effects of the principal temporary differences between financial reporting and income tax reporting are as follows:


	December 31,
	2025		2024
Property, plant and equipment	$	(1,199)	$	(1,323)
Turnaround costs	(347)		(223)
Total deferred tax liabilities	$	(1,546)	$	(1,546)

Balance sheet classifications

Noncurrent deferred tax liability	$	(1,546)	$	(1,546)
Total deferred tax liabilities	$	(1,546)	$	(1,546)

Related Party Transactions Related Party Transactions (Major Customer and Credit Risk) (Details)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Revenue Benchmark \| Westlake \| Customer Concentration Risk \| Affiliated Entity
Related Party Transaction [Line Items]
Concentration Risk, Percentage	88.60%	83.70%	86.20%

- 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

- Definition

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.

+ References

+ Details

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%

Partners' Equity	12 Months Ended
Partners' Equity	Dec. 31, 2025
Equity [Abstract]
Partners' Equity	Partners' Equity On October 4, 2018, the Partnership and Westlake Chemical Partners GP LLC, the general partner of the Partnership, entered into an Equity Distribution Agreement with UBS Securities LLC, Barclays Capital Inc., Citigroup Global Markets Inc., Deutsche Bank Securities Inc., RBC Capital Markets, LLC, Merrill Lynch, Pierce, Fenner & Smith Incorporated and Wells Fargo Securities, LLC to offer and sell the Partnership's common units, from time to time, up to an aggregate offering amount of $50,000. The Equity Distribution Agreement was amended on February 28, 2020 to reference a new shelf registration and subsequent renewals thereof for utilization under this agreement. To date, no common units have been issued under this program. On March 29, 2019, the Partnership completed the issuance and sale of 2,940,818 common units at a price of $21.40 per unit through a private placement. TTWF LP, Westlake's principal stockholder and a related party, acquired 1,401,869 common units out of 2,940,818 common units issued in the private placement.

- Definition

The entire disclosure for equity.

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+ Details

Agreements with Westlake and Related Parties (Details)			12 Months Ended
Agreements with Westlake and Related Parties (Details)	Oct. 28, 2025	Aug. 04, 2014 USD ($) lease lb $ / lb	Dec. 31, 2025 USD ($) lb $ / lb	Dec. 31, 2024 USD ($)
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Term of Investment Management Agreement with Related Party, Maximum			9 months
IMA, Partnership earned amount added to market rate, basis points			five
Receivables under Investment Management Agreements with Related Parties, Current \| $			$ 23,378,000	$ 134,557,000
Westlake Chemical OpCo LP \| Ethylene Sales Agreement \| Investee
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Long-Term Purchase Commitment, Renewal Term	12 months
Westlake Chemical OpCo LP \| Feedstock Supply Agreement \| Investee
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Long-Term Purchase Commitment, Renewal Term	12 months
Westlake Chemical OpCo LP \| Exchange Agreement
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Purchase commitment, fixed margin on variable pricing \| $ / lb			0.006
Exchange agreement amount of purchase agreement \| lb			200,000,000
Westlake Chemical OpCo LP \| Westlake \| Ethylene Sales Agreement \| Investee
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Minimum percentage required to be purchased		95.00%
Maximum mass required to be purchased \| lb		3,800,000,000
Long-term Purchase Commitment, Excess Production Percentage		95.00%
Number of years used to calculate average expenses		5 years
Purchase commitment, fixed margin on variable pricing \| $ / lb		0.10
Long-term Purchase Commitment, Curtail Option Percentage		5.00%
Long-term Purchase Commitment, Compliance Surcharge Amount \| $		$ 500,000
Westlake Chemical OpCo LP \| Westlake \| Excess Production Option \| Investee
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Purchase commitment, fixed margin on variable pricing \| $ / lb		0.10
Westlake Chemical OpCo LP \| Westlake \| Feedstock Supply Agreement \| Investee
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Long-Term Purchase Commitment, Renewal Term			12 months
Westlake Chemical OpCo LP \| Westlake \| Services And Secondment Agreement \| Investee
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Period of default in performance that can allow a party to terminate agreement		30 days
Westlake Chemical OpCo LP \| Westlake \| Site Lease Agreement \| Investee
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Number of lease agreements \| lease		2
Operating lease, rental amount \| $		$ 1
Term of operating lease		50 years

Related Party Transactions (Goods and Services from Related Parties that have been Capitalized) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Affiliated Entity \| Westlake
Related Party Transaction [Line Items]
Goods and services purchased from Westlake and capitalized as assets	$ 7,311	$ 2,295	$ 3,660

- Definition

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.

+ References

+ Details

Distributions and Net Income Per Limited Partner Unit (Incentive Distribution Rights) (Details)	12 Months Ended
	Dec. 31, 2025 $ / shares
Above $1.2938 up to $1.4063 \| Unitholders
Distribution Made to Limited Partner [Line Items]
Marginal Percentage Interest in Distributions	85.00%
Above $1.2938 up to $1.4063 \| IDR Holders
Distribution Made to Limited Partner [Line Items]
Marginal Percentage Interest in Distributions	15.00%
Above $1.4063 up to $1.6875 \| Unitholders
Distribution Made to Limited Partner [Line Items]
Marginal Percentage Interest in Distributions	75.00%
Above $1.4063 up to $1.6875 \| IDR Holders
Distribution Made to Limited Partner [Line Items]
Marginal Percentage Interest in Distributions	25.00%
Above $1.6875 \| Unitholders
Distribution Made to Limited Partner [Line Items]
Marginal Percentage Interest in Distributions	50.00%
Above $1.6875 \| IDR Holders
Distribution Made to Limited Partner [Line Items]
Marginal Percentage Interest in Distributions	50.00%
Minimum \| Above $1.2938 up to $1.4063
Distribution Made to Limited Partner [Line Items]
Quarterly distribution per unit threshold (usd per share)	$ 1.2938
Minimum \| Above $1.4063 up to $1.6875
Distribution Made to Limited Partner [Line Items]
Quarterly distribution per unit threshold (usd per share)	1.4063
Minimum \| Above $1.6875
Distribution Made to Limited Partner [Line Items]
Quarterly distribution per unit threshold (usd per share)	1.6875
Maximum \| Above $1.2938 up to $1.4063
Distribution Made to Limited Partner [Line Items]
Quarterly distribution per unit threshold (usd per share)	1.4063
Maximum \| Above $1.4063 up to $1.6875
Distribution Made to Limited Partner [Line Items]
Quarterly distribution per unit threshold (usd per share)	$ 1.6875

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

- Definition

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.

+ References

+ Details

Distributions and Net Income Per Limited Partner Unit (Income In Excess Of Distribution) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Limited Partners' Capital Account [Line Items]
Limited partners' interest in net income subsequent to IPO	$ 48,698	$ 62,392	$ 54,283
Limited partners' distribution declared on common units	66,453	66,437	66,421
Distribution in excess of net income	(17,755)	(4,045)	(12,138)
Common units
Limited Partners' Capital Account [Line Items]
Limited partners' interest in net income subsequent to IPO	48,698	62,392	54,283
Limited partners' distribution declared on common units	66,453	66,437	66,421
Distribution in excess of net income	$ (17,755)	$ (4,045)	$ (12,138)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Distributions and Net Income Per Limited Partner Unit

12 Months Ended

Dec. 31, 2025

Earnings Per Share [Abstract]

Distributions and Net Income Per Limited Partner Unit

On January 27, 2026, the board of directors of Westlake Chemical Partners GP LLC ("Westlake GP"), the Partnership's general partner, declared a quarterly cash distribution for the period from October 1, 2025 to December 31, 2025 of $0.4714 per common unit. This distribution was paid on February 23, 2026 to unitholders of record as of February 6, 2026.

Distributions are declared subsequent to quarter end; therefore, the table below represents total cash distributions declared from earnings of the related periods pertaining to such distributions.


	Year Ended December 31,
		2025		2024		2023
Net income attributable to the Partnership		$	48,698	$	62,392	$	54,283
Less:
Limited partners' distribution declared on common units		66,453		66,437		66,421


Distribution in excess of net income		$	(17,755)	$	(4,045)	$	(12,138)

Net income per unit applicable to common limited partner units is computed by dividing the respective limited partners' interest in net income by the weighted-average number of common units outstanding for the period. Because the Partnership has more than one class of participating securities, it uses the two-class method when calculating the net income per unit applicable to limited partners. The classes of participating securities include common units and incentive distribution rights. Net income attributable to the Partnership is allocated to the unitholders in accordance with their respective ownership percentages in preparation of the consolidated statements of changes in equity. However, when distributions related to the incentive distribution rights are made, net income equal to the amount of those distributions is first allocated to the general partner before the remaining net income is allocated to the unitholders based on their respective ownership percentages. Basic and diluted net income per unit is the same because the Partnership does not have any potentially dilutive units outstanding for the periods presented.


	Year Ended December 31, 2025
	Limited Partners' Common Units		Incentive Distribution Rights		Total
Net income attributable to the Partnership:
Distribution	$	66,453	$	—	$	66,453
Distribution in excess of net income	(17,755)		—		(17,755)
Net income	$	48,698	$	—	$	48,698
Weighted average units outstanding:
Basic and diluted	35,241,505				35,241,505
Net income per limited partner unit:
Basic and diluted	$	1.38


	Year Ended December 31, 2024
	Limited Partners' Common Units		Incentive Distribution Rights		Total
Net income attributable to the Partnership:
Distribution	$	66,437	$	—	$	66,437
Distribution in excess of net income	(4,045)		—		(4,045)
Net income	$	62,392	$	—	$	62,392
Weighted average units outstanding:
Basic and diluted	35,232,870				35,232,870
Net income per limited partner unit:
Basic and diluted	$	1.77


	Year Ended December 31, 2023
	Limited Partners' Common Units		Incentive Distribution Rights		Total
Net income attributable to the Partnership:
Distribution	$	66,421	$	—	$	66,421
Distribution in excess of net income	(12,138)		—		(12,138)
Net income	$	54,283	$	—	$	54,283
Weighted average units outstanding:
Basic and diluted	35,224,340				35,224,340
Net income per limited partner unit:
Basic and diluted	$	1.54


	Marginal Percentage Interest in Distributions
Total Quarterly Distribution Per Unit	Unitholders		IDR Holders
Above $1.2938 up to $1.4063	85.0	%	15.0	%
Above $1.4063 up to $1.6875	75.0	%	25.0	%
Above $1.6875	50.0	%	50.0	%

Distribution Per Common Unit

Distributions per common unit for the years ended December 31, 2025, 2024 and 2023 were as follows:


	Year Ended December 31,
	2025		2024		2023
Distributions per common unit	$	1.8856	$	1.8856	$	1.8856

Cover Page - USD ($) $ in Millions	12 Months Ended
Cover Page - USD ($) $ in Millions	Dec. 31, 2025	Feb. 25, 2026	Jun. 30, 2025
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2025
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-36567
Entity Registrant Name	Westlake Chemical Partners LP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	32-0436529
Entity Address, Address Line One	2801 Post Oak Boulevard
Entity Address, Address Line Two	Suite 600
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77056
City Area Code	713
Local Phone Number	585-2900
Title of 12(b) Security	Common units representing limited partner interests
Trading Symbol	WLKP
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 425.6
Entity Common Stock, Shares Outstanding		35,245,879
Amendment Flag	false
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	FY
Entity Central Index Key	0001604665

Deferred Charges and Other Assets (Schedule Of Intangible and Other Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Other Assets [Abstract]
Turnaround costs, net	$ 213,953	$ 129,565
Other	7,248	8,063
Deferred charges and other assets, net	221,201	137,628
Deferred Charges and Other Assets [Line Items]
Amortization	$ 40,960	$ 25,646	$ 25,692
Minimum
Deferred Charges and Other Assets [Line Items]
Other assets amortization period	3 years
Maximum
Deferred Charges and Other Assets [Line Items]
Other assets amortization period	20 years

- Definition

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.

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+ Details

Unit-based Compensation

12 Months Ended

Dec. 31, 2025

Share-Based Payment Arrangement [Abstract]

Unit-based Compensation

The Westlake Chemical Partners LP Long-Term Incentive Plan (the "Plan") was adopted on July 15, 2014 and provides for grants of unit options, restricted units, phantom units, unit awards, distribution equivalent rights ("DERs") and other unit-based awards. The purpose of the Plan is to attract and retain the services of individuals who are essential for the growth and profitability of the Partnership and to encourage such individuals to devote their best efforts to advancing the business of the Partnership and its affiliates. Awards under the Plan are determined by the board of directors of the Partnership's general partner or a committee thereof (the "Committee"). Under the Plan, DERs may be granted, which represent a contingent right to receive an amount in cash, units, restricted units and/or phantom units, as determined by the Committee at its sole discretion, equal in value to the cash distributions made by the Partnership with respect to a common unit during the period such award is outstanding. The terms and conditions of each award are determined by the Committee. The maximum number of common units of the Partnership that may be delivered with respect to awards under the Plan is 1,270,000. The phantom units along with a corresponding number of DERs were granted to certain non-employee directors of the general partner of the Partnership during the years ended December 31, 2025, 2024 and 2023. These phantom units vest on the first anniversary of the grant date. There were no forfeitures under the Plan during 2025, 2024 and 2023. The total fair value of phantom units that vested during the years ended December 31, 2025, 2024 and 2023 was $322, $423 and $278, respectively.

Non-vested phantom unit awards as of December 31, 2025 and 2024 and changes during the period were as follows:


	Number of Units	Weighted Average Fair Value



Non-vested balance at December 31, 2024	14,646	$	23.14
Granted	15,015	21.92
Vested	(14,646)	21.96
Non-vested balance at December 31, 2025	15,015	$	19.00

Each phantom unit represents the right to receive, upon vesting, either a cash payment equal to the fair market value of one Partnership common unit or a Partnership common unit. Each DER has distribution rights only so long as the phantom units to which it relates to has not vested or been settled.

The awards, which are classified as liability awards for financial accounting purposes, are measured at fair value on the grant date of the award and are re-measured at each reporting date until they vest based on the market price of the Partnership's units. The total units available for grant at December 31, 2025 were 1,184,657. The total compensation cost recognized during the years ended December 31, 2025, 2024 and 2023 was $301, $373 and $349, respectively, and is included in selling, general and administrative expenses and the related liability is classified as accrued and other liabilities in the consolidated financial statements of the Partnership. The unrecognized compensation cost associated with all grants under the Plan at December 31, 2025 was $169 and the weighted average remaining term of the units at December 31, 2025 was 0.6 years.

Distributions and Net Income Per Limited Partner Unit (Narrative) (Details) - $ / shares		12 Months Ended
	Jan. 27, 2026	Dec. 31, 2025
Above $1.2938 up to $1.4063 \| Minimum
Distributions [Line Items]
Quarterly distribution per unit threshold (usd per share)		$ 1.2938
Common and Subordinated units \| Cash Distribution
Distributions [Line Items]
Minimum quarterly distribution per unit (usd per share)		$ 1.2938
Common and Subordinated units \| Cash Distribution \| Subsequent Event
Distributions [Line Items]
Distribution declared per unit (usd per share)	$ 0.4714

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2025
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Partnership is subject to environmental laws and regulations that can impose civil and criminal sanctions and that may require the Partnership to mitigate the effects of contamination caused by the release or disposal of hazardous substances into the environment. These laws include the federal Clean Air Act, the federal Water Pollution Control Act, the Resource Conservation and Recovery Act, the Comprehensive Environmental Response, Compensation, and Liability Act ("CERCLA"), the Toxic Substances Control Act and various other federal, state and local laws and regulations. Under CERCLA, an owner or operator of property may be held strictly liable for remediating contamination without regard to whether that person caused the contamination, and without regard to whether the practices that resulted in the contamination were legal at the time they occurred. Because the Partnership's production sites have a history of industrial use, it is impossible to predict precisely what effect these legal requirements will have on the Partnership. Pursuant to the Omnibus Agreement, certain subsidiaries of Westlake will indemnify the Partnership for certain environmental and other liabilities that occurred or existed prior to August 4, 2014. Pursuant to the Services and Secondment Agreement, certain subsidiaries of Westlake will indemnify the Partnership for certain liabilities incurred in connection with the performance of Westlake's services under such agreement. The Partnership is also involved in other legal proceedings incidental to the conduct of its business. After considering all relevant facts and circumstances, including applicable insurance and indemnification by Westlake, the Partnership does not believe that any of these legal proceedings will have a material adverse effect on its financial condition, results of operations or cash flows. Other Commitments The Partnership has various purchase commitments for its capital projects and for materials, supplies and services incident to the ordinary conduct of business.

Description of Business and Significant Accounting Policies (Narrative) (Details) $ in Thousands			12 Months Ended
	Mar. 29, 2019 shares	Aug. 04, 2014 shares	Dec. 31, 2025 USD ($) production_facility numberOfCommonCarrierPipelines	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Threshold period past due accounts receivable reviewed			90 days
Capitalized interest			$ 79	$ 197	$ 164
Goodwill			$ 5,814	$ 5,814
Amortization period, minimum (in years)			5 years
Amortization period, maximum (in years)			8 years
Limited Liability Company \| Westlake Chemical OpCo GP LLC \| Westlake Chemical Partners LP
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Partnership's ownership interest (percent)		100.00%
Affiliated Entity \| Westlake Chemical OpCo LP \| Westlake Chemical Partners LP
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Partnership's ownership interest (percent)	22.80%
Westlake \| Majority-Owned Subsidiary, Unconsolidated \| Westlake Chemical OpCo LP \| Westlake Chemical Corporation
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Partnership's ownership interest (percent)	77.20%
Westlake Chemical OpCo LP
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of production facilities \| production_facility			3
Number of common carrier pipelines \| numberOfCommonCarrierPipelines			1
Limited Partner
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of units sold in public offering \| shares	2,940,818	12,937,500

Accounts Receivable—Third Parties (Schedule Of Accounts Receivable) (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Accounts Receivable, after Allowance for Credit Loss [Abstract]
Trade customers	$ 9,283	$ 11,757
Allowance for credit losses	(170)	(181)
Accounts receivable, net—third parties	$ 9,113	$ 11,576

Fair Value Measurements

12 Months Ended

Dec. 31, 2025

Fair Value Disclosures [Abstract]

Fair Value Measurements

The Partnership reports certain assets and liabilities at fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). Under the accounting guidance for fair value measurements, inputs used to measure fair value are classified in one of three levels:

Level 1: Quoted market prices in active markets for identical assets or liabilities.

Level 2: Observable market-based inputs or unobservable inputs that are corroborated by market data.

Level 3: Unobservable inputs that are not corroborated by market data.

The Partnership has financial assets and liabilities subject to fair value measures. These financial assets and liabilities include cash and cash equivalents, accounts receivable, net, accounts payable and long-term debt payable to Westlake, all of which are recorded at carrying value. The amounts reported in the consolidated balance sheets for cash and cash equivalents, accounts receivable, net and accounts payable approximate their fair value due to the short maturities of these instruments. The carrying and fair values of the Partnership's long-term debt at December 31, 2025 and December 31, 2024 are summarized in the table below. The fair value of long-term debt is determined based on the present value of expected future cash flows using a discounted cash flow methodology. Because the Partnership's valuation methodology used for long-term debt requires the use of significant unobservable inputs, the inputs used to measure the fair value of the Partnership's long-term debt are classified as Level 3 within the fair value hierarchy. Inputs used to estimate the fair values of the Partnership's long-term debt include the selection of an appropriate discount rate.


	December 31, 2025				December 31, 2024
	Carrying Value		Fair Value		Carrying Value		Fair Value


Long-term debt payable to Westlake	$	399,674	$	408,780	$	399,674	$	411,489

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
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+ Details

Inventories (Tables)

12 Months Ended

Dec. 31, 2025

Inventory, Net [Abstract]

Schedule Of Inventory

Inventories consist of the following:


	December 31,
	2025		2024
Finished products	$	2,336	$	3,748
Feedstock, additives and chemicals	433		310
Inventories	$	2,769	$	4,058

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2025

Property, Plant and Equipment, Net [Abstract]

Property, Plant and Equipment

Property, plant and equipment consist of the following:


	December 31,
	2025		2024

Building and improvements	$	18,774	$	18,562
Plant and equipment	2,020,193		1,950,479
Other	124,517		118,870
	2,163,484		2,087,911
Less: Accumulated depreciation	(1,293,700)		(1,237,929)
	869,784		849,982
Construction in progress	16,228		53,606
Property, plant and equipment, net	$	886,012	$	903,588

Depreciation expense on property, plant and equipment of $87,018, $86,253 and $84,511 is included in cost of sales in the consolidated statements of operations for the years ended December 31, 2025, 2024 and 2023, respectively.

Related Party Transactions (General) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Related Party Transaction [Line Items]
Income taxes paid	$ 873	$ 831	$ 827
Affiliated Entity \| Reimbursement to Parent for State Tax \| Westlake
Related Party Transaction [Line Items]
Income taxes paid	$ 333	$ 351	$ 347

- Definition

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.

+ References

+ Details

Distributions and Net Income Per Limited Partner Unit (Basic and Diluted Income Per Limited Partner Unit) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Limited Partners' Capital Account [Line Items]
Distribution	$ 66,453	$ 66,437	$ 66,421
Distribution in excess of net income	(17,755)	(4,045)	(12,138)
Limited partners' interest in net income subsequent to IPO	$ 48,698	$ 62,392	$ 54,283
Weighted average limited partner units outstanding (basic and diluted)	35,241,505	35,232,870	35,224,340
IDR Holders
Limited Partners' Capital Account [Line Items]
Distributions declared with respect to the incentive distribution rights	$ 0	$ 0	$ 0
Distribution in excess of net income	0	0	0
Limited partners' interest in net income subsequent to IPO	0	0	0
Common units
Limited Partners' Capital Account [Line Items]
Distribution	66,453	66,437	66,421
Distribution in excess of net income	(17,755)	(4,045)	(12,138)
Limited partners' interest in net income subsequent to IPO	$ 48,698	$ 62,392	$ 54,283
Weighted average limited partner units outstanding (basic and diluted)	35,241,505	35,232,870	35,224,340
Common units	$ 1.38	$ 1.77	$ 1.54
Diluted units	$ 1.38	$ 1.77	$ 1.54

Fair Value Measurements (Schedule Of Carrying And Fair Values Of Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt payable to Westlake, fair value	$ 408,780	$ 411,489
Westlake \| Affiliated Entity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt payable to Westlake	$ 399,674	$ 399,674

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

Distributions and Net Income Per Limited Partner Unit (Distributions per common unit) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Earnings Per Share [Abstract]
Distributions per common unit	$ 1.8856	$ 1.8856	$ 1.8856

Partners' Equity (Incentive Distribution Rights) (Details) - USD ($) $ / shares in Units, $ in Thousands	Mar. 29, 2019	Oct. 04, 2018	Aug. 04, 2014
Class of Stock [Line Items]
Partners units, maximum aggregate offering amount, ATM		$ 50,000
Affiliated Entity
Class of Stock [Line Items]
Partners' capital account, units, sold to related party	1,401,869
Limited Partner
Class of Stock [Line Items]
Number of units sold in public offering	2,940,818		12,937,500
Units sold in secondary offering price per unit	$ 21.40

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Audit Information	12 Months Ended
Audit Information	Dec. 31, 2025
Auditor [Abstract]
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Houston, Texas
Auditor Firm ID	238

Related Party Transactions (Services from Related Parties Included in SG&A Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Related Party Transaction [Line Items]
Services received from Westlake and included in selling, general and administrative expenses	$ 28,271	$ 28,495	$ 29,751
Affiliated Entity \| Westlake
Related Party Transaction [Line Items]
Services received from Westlake and included in selling, general and administrative expenses	$ 25,017	$ 25,654	$ 27,085

- Definition

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.

+ References

+ Details

- Definition

The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

+ References + Details

Income Taxes (Reconciliation Of Taxes Computed At The Statutory Rate To Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Amount
Provision for federal income tax, at statutory rate	$ 62,816	$ 77,699	$ 70,442
State income tax provision, net of federal income tax effect (1)	547	835	813
Partnership income not subject to entity-level federal income tax	(62,816)	(77,699)	(70,442)
Total provision	$ 547	$ 835	$ 813
Percentage
Provision for federal income tax, at statutory rate	21.00%
State income tax provision, net of federal income tax effect (1)	0.20%
Partnership income not subject to entity-level federal income tax	(21.00%)
Total provision	0.20%

Consolidated Balance Sheets (Parenthetical) - Common units - shares	Dec. 31, 2025	Dec. 31, 2024
Publicly and Privately Held
Units issued	21,123,649	21,116,326
Units outstanding	21,123,649	21,116,326
Westlake
Units issued	14,122,230	14,122,230
Units outstanding	14,122,230	14,122,230

Long-Term Debt

12 Months Ended

Dec. 31, 2025

Debt Disclosure [Abstract]

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.

Supplemental Information (Income Taxes Paid by Jurisdiction) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Income Tax Paid, by Individual Jurisdiction [Line Items]
Income taxes paid	$ 873	$ 831	$ 827
State and Local Jurisdiction
Income Tax Paid, by Individual Jurisdiction [Line Items]
Income taxes paid	540	$ 480	$ 480
Kentucky
Income Tax Paid, by Individual Jurisdiction [Line Items]
Income taxes paid	540
Texas
Income Tax Paid, by Individual Jurisdiction [Line Items]
Income taxes paid	$ 333

Goodwill	12 Months Ended
Goodwill	Dec. 31, 2025
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill The Partnership's goodwill balance was $5,814 at December 31, 2025 and 2024. The Partnership performed its annual goodwill impairment analysis during the fourth quarter of 2025. The Partnership elected to perform a qualitative assessment for its analysis. Based upon this assessment, the Partnership concluded that it is more likely than not that the fair value of the reporting unit exceeds the carrying amount. Factors considered in the qualitative assessment included industry and market considerations, cost factors, including consideration of the Partnership's fixed margin under the Ethylene Sales Agreement, and current and projected financial performance.

- Definition

The entire disclosure for goodwill.

+ References + Details

Supplemental Information

12 Months Ended

Dec. 31, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Supplemental Information

Accrued and Other Liabilities

Accrued and other liabilities were $22,199 and $16,920 at December 31, 2025 and 2024, respectively. Accrued maintenance, accrued turnaround costs, and accrued interest on related party debt, which are components of accrued and other liabilities, were $2,764, $6,372, and $5,508, respectively, at December 31, 2025 and $1,458, $933, and $5,848, respectively, at December 31, 2024. No other component of accrued and other liabilities was more than five percent of total current liabilities.

Insurance Recoveries

During the year ended December 31, 2024, the Partnership recorded business interruption related insurance recoveries of $6,222 as a reduction to cost of sales. All insurance recovery proceeds were collected as of December 31, 2024. These recoveries were related to the settlement of insurance claims for Hurricane Laura, which impacted OpCo's Petro 1 and Petro 2 units in the second half of 2020 and impacted production in the subsequent periods.

Cash Flow Information

Non-cash Investing Activity

Capital expenditure related liabilities, included in accounts payable—third parties and accrued and other liabilities, were $3,243, $9,863, and $7,809 at December 31, 2025, 2024, and 2023, respectively.

Interest and Income Taxes

Interest paid by the Partnership, net of interest capitalized, was $23,237, $26,528 and $24,537 for the years ended December 31, 2025, 2024 and 2023, respectively. Income tax paid by the Partnership was $873, $831 and $827 for the years ended December 31, 2025, 2024 and 2023, respectively, of which $540, $480 and $480 was paid directly to the tax authorities for the years ended December 31, 2025, 2024 and 2023, and $333, $351 and $347 was paid to Westlake as reimbursements for the years ended December 31, 2025, 2024 and 2023.

The Partnership's income taxes paid are presented in accordance with ASU 2023-09 and the standard is applied prospectively. The Partnership's payment of income taxes by jurisdiction is as follows:


	Year Ended December 31,
	2025
Kentucky	$	540
Texas	333
Total income taxes paid	$	873

Operating Leases

Right-of-use assets obtained in exchange for operating lease obligations were $920, $758 and $5,079 for the years ended December 31, 2025, 2024 and 2023, respectively.

Related Party Transactions (Accounts Receivable from and Accounts Payable to Related Parties) (Details) - Affiliated Entity - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Related Party Transaction [Line Items]
Accounts receivable, net—Westlake	$ 63,571	$ 31,975
Accounts payable—third parties	$ 19,132	$ 20,744

- Definition

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.

+ References

+ Details

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2025

Fair Value Disclosures [Abstract]

Schedule Of Carrying And Fair Values Of Long-Term Debt

The carrying and fair values of the Partnership's long-term debt at December 31, 2025 and December 31, 2024 are summarized in the table below. The fair value of long-term debt is determined based on the present value of expected future cash flows using a discounted cash flow methodology. Because the Partnership's valuation methodology used for long-term debt requires the use of significant unobservable inputs, the inputs used to measure the fair value of the Partnership's long-term debt are classified as Level 3 within the fair value hierarchy. Inputs used to estimate the fair values of the Partnership's long-term debt include the selection of an appropriate discount rate.


	December 31, 2025				December 31, 2024
	Carrying Value		Fair Value		Carrying Value		Fair Value


Long-term debt payable to Westlake	$	399,674	$	408,780	$	399,674	$	411,489

Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2025

Debt Disclosure [Abstract]

Schedule Of 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

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
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-Paragraph 1
-Subparagraph (SX 210.5-02(22))
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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-Paragraph 2
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-URI https://asc.fasb.org/1943274/2147477314/942-235-S99-2

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 6: http://www.xbrl.org/2003/role/exampleRef
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+ Details

Segment Information (Details) $ in Thousands	12 Months Ended
Segment Information (Details) $ in Thousands	Dec. 31, 2025 USD ($) segment	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments \| segment	1
Number of reportable segments \| segment	1
Depreciation and amortization	$ 127,978	$ 111,899	$ 110,203
Cost of sales	818,847	716,957	803,332
Selling, general and administrative expenses	28,271	28,495	29,751
Interest expense—Westlake	22,899	25,701	26,501
Net income	298,576	369,159	334,626
Assets	1,256,533	1,287,956
Operating Segments \| OpCo
Segment Reporting Information [Line Items]
Raw material, energy, manufacturing and logistics costs	690,869	605,058	693,129
Depreciation and amortization	127,978	111,899	110,203
Cost of sales	818,847	716,957	803,332
Selling, general and administrative expenses	24,853	24,699	26,217
Other segment items	(582)	(3,005)	(1,786)
Interest expense—Westlake	1,316	1,410	1,496
Net income	323,577	397,245	363,028
Assets	1,222,123	1,238,420
Corporate
Segment Reporting Information [Line Items]
Interest expense—Westlake	21,583	24,291	25,005
Net income	(25,001)	(28,086)	(28,402)
Assets	34,410	49,536
Affiliated Entity
Segment Reporting Information [Line Items]
Net co-products, ethylene and other sales—third parties	$ 1,033,276	$ 950,801	$ 1,026,655

Related Party Transactions (Receivable under the Investment Management Agreement) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Related Party Transaction [Line Items]
IMA, Partnership earned amount added to market rate, basis points	five
Receivable under the Investment Management Agreement—Westlake Corporation ("Westlake")	$ 23,378	$ 134,557
Westlake \| Affiliated Entity
Related Party Transaction [Line Items]
Interest earned related to the IMA	2,539	5,364	$ 4,424
Westlake \| Affiliated Entity \| Accounts Receivable
Related Party Transaction [Line Items]
Accrued interest included in receivable under IMA	$ 206	$ 1,385

- Definition

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.

+ References

+ Details

Inventories

12 Months Ended

Dec. 31, 2025

Inventory, Net [Abstract]

Inventories

Inventories consist of the following:


	December 31,
	2025		2024
Finished products	$	2,336	$	3,748
Feedstock, additives and chemicals	433		310
Inventories	$	2,769	$	4,058

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Cash flows from operating activities
Net income	$ 298,576	$ 369,159	$ 334,626
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	127,978	111,899	110,203
Loss from disposition of property, plant and equipment	2,754	2,345	4,933
Other gains, net	(11)	(182)	(27)
Changes in operating assets and liabilities
Accounts receivable—third parties	2,474	7,221	1,332
Net accounts receivable—Westlake	(32,029)	25,737	27,331
Inventories	1,289	374	283
Prepaid expenses and other current assets	38	(2)	(137)
Accounts payable—third parties	(2,353)	(2,693)	1,569
Accrued and other liabilities	6,915	(5,821)	4,026
Deferred charges and other assets and others, net	(125,162)	(23,036)	(32,140)
Net cash provided by operating activities	280,469	485,001	451,999
Cash flows from investing activities
Additions to property, plant and equipment	(78,817)	(48,971)	(46,821)
Investments with Westlake under the Investment Management Agreement	(10,000)	(40,000)	(174,116)
Maturities of investments with Westlake under the Investment Management Agreement	120,000	0	145,000
Net cash provided by (used for) investing activities	31,183	(88,971)	(75,937)
Cash flows from financing activities
Proceeds from debt payable to Westlake	173,500	219,000	209,250
Repayment of debt payable to Westlake	(173,500)	(219,000)	(209,250)
Distributions to noncontrolling interest retained in OpCo by Westlake	(259,247)	(329,898)	(315,805)
Distributions to unitholders	(66,452)	(66,435)	(66,420)
Net cash used for financing activities	(325,699)	(396,333)	(382,225)
Net decrease in cash and cash equivalents	(14,047)	(303)	(6,163)
Cash and cash equivalents at beginning of the year	58,316	58,619	64,782
Cash and cash equivalents at end of the year	$ 44,269	$ 58,316	$ 58,619

Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Noncontrolling Interest in OpCo	Westlake General Partner	Common units Publicly and Privately Held Limited Partner	Common units Westlake Limited Partner
Equity, beginning balance at Dec. 31, 2022	$ 903,708	$ 611,778	$ (242,572)	$ 480,643	$ 53,859
Stockholders' Equity [Roll Forward]
Net income	334,626	280,343	0	32,519	21,764
Units issued for vested phantom units	141			141
Distribution to unitholders	(66,420)			(39,790)	(26,630)
Distribution to noncontrolling interest retained in OpCo by Westlake	(315,805)	(315,805)
Equity, ending balance at Dec. 31, 2023	856,250	576,316	(242,572)	473,513	48,993
Stockholders' Equity [Roll Forward]
Net income	369,159	306,767	0	37,384	25,008
Units issued for vested phantom units	238			238
Distribution to unitholders	(66,435)			(39,807)	(26,628)
Distribution to noncontrolling interest retained in OpCo by Westlake	(329,898)	(329,898)
Equity, ending balance at Dec. 31, 2024	829,314	553,185	(242,572)	471,328	47,373
Stockholders' Equity [Roll Forward]
Net income	298,576	249,878	0	29,183	19,515
Units issued for vested phantom units	161			161
Distribution to unitholders	(66,452)			(39,824)	(26,628)
Distribution to noncontrolling interest retained in OpCo by Westlake	(259,247)	(259,247)
Equity, ending balance at Dec. 31, 2025	$ 802,352	$ 543,816	$ (242,572)	$ 460,848	$ 40,260

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
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+ Details

Supplemental Information (Insurance Recoveries) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2025 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Insurance Recoveries	$ 6,222

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Current assets
Cash and cash equivalents	$ 44,269	$ 58,316
Receivable under the Investment Management Agreement—Westlake Corporation ("Westlake")	23,378	134,557
Accounts receivable, net—third parties	9,113	11,576
Inventories	2,769	4,058
Prepaid expenses and other current assets	406	444
Total current assets	143,506	240,926
Property, plant and equipment, net	886,012	903,588
Goodwill	5,814	5,814
Deferred charges and other assets, net	221,201	137,628
Total assets	1,256,533	1,287,956
Current liabilities
Accrued and other liabilities	22,199	16,920
Total current liabilities	51,301	55,372
Deferred income taxes	1,546	1,546
Other liabilities	1,660	2,050
Total liabilities	454,181	458,642
Commitments and contingencies (Note 16)
EQUITY
Total Westlake Chemical Partners LP partners' capital	258,536	276,129
Noncontrolling interest in Westlake Chemical OpCo LP ("OpCo")	543,816	553,185
Total equity	802,352	829,314
Total liabilities and equity	1,256,533	1,287,956
Affiliated Entity
Current assets
Accounts receivable, net—Westlake	63,571	31,975
Current liabilities
Accounts payable—third parties	19,132	20,744
Nonrelated Party
Current assets
Accounts receivable, net—third parties	9,113	11,576
Current liabilities
Accounts payable—third parties	9,970	17,708
Westlake
EQUITY
General partner—Westlake	(242,572)	(242,572)
Westlake \| Affiliated Entity
Current liabilities
Long-term debt payable to Westlake	399,674	399,674
Common units \| Publicly and Privately Held
EQUITY
Limited partners' capital	460,848	471,328
Common units \| Westlake
EQUITY
Limited partners' capital	$ 40,260	$ 47,373

Description of Business and Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description Of Business	Description of Business Westlake Chemical Partners LP (the "Partnership") is a Delaware limited partnership formed in March 2014 to operate, acquire and develop ethylene production facilities and related assets. On August 4, 2014, the Partnership completed its initial public offering of 12,937,500 common units representing limited partner interests. The Partnership owns 22.8% limited partner interest in Westlake Chemical OpCo LP ("OpCo") and a 100% interest in Westlake Chemical OpCo GP LLC ("OpCo GP"), which is the general partner of OpCo. OpCo owns three ethylene production facilities and one common carrier ethylene pipeline (collectively, the "Contributed Assets"). The remaining 77.2% limited partner interest in OpCo is owned by Westlake Corporation. References to "Westlake" refer collectively to Westlake Corporation and its subsidiaries, other than the Partnership, OpCo and OpCo GP. OpCo and Westlake entered into an ethylene sales agreement (the "Ethylene Sales Agreement") pursuant to which the Partnership generates a substantial majority of its revenue. For more information, see Note 2.
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in conformity with the accounting principles generally accepted in the United States. The Partnership holds a 22.8% limited partner interest and the entire non-economic general partner interest in OpCo. The remaining 77.2% limited partner interest in OpCo is owned directly by Westlake, which has no rights to direct the activities that most significantly impact the economic performance of OpCo. As a result of the fact that substantially all of OpCo's activities are conducted on behalf of Westlake, and the fact that OpCo exhibits disproportionality of voting rights to economic interest, OpCo was deemed to be a variable interest entity. The Partnership, through its ownership of OpCo's general partner, has the power to direct the activities that most significantly impact the economic performance of OpCo, and it also has the obligation or right to absorb losses or receive benefits from OpCo that could potentially be significant to OpCo. As such, the Partnership was determined to be OpCo's primary beneficiary and therefore consolidates OpCo's results of operations and financial position. The Partnership's operations consist exclusively of the variable interest entity's operations and, as such, no additional variable interest entity disclosures are considered necessary. Westlake's retained interest of 77.2% is recorded as noncontrolling interest in the Partnership's consolidated financial statements.
Cash And Cash Equivalents	Cash and Cash Equivalents Cash equivalents consist of highly liquid investments that are readily convertible into cash and have a maturity of three months or less at the date of acquisition.
Allowance For Doubtful Accounts	Allowance for Credit Losses The determination of the allowance for credit losses is based on estimation of the amount of accounts receivable that the Partnership believes are unlikely to be collected. Estimating this amount requires analysis of the financial strength of the Partnership's customers, the use of historical experience, the Partnership's accounts receivable aged trial balance, customer specific collectability analysis and an evaluation of economic conditions. The allowance for credit losses is reviewed quarterly. Past due balances over 90 days and high risk accounts, as determined by the analysis of financial strength of customers, are reviewed individually for collectability.
Inventories	Inventories Inventories primarily include product, material and supplies. Inventories are stated at the lower of cost or net realizable value. Cost is determined using the first-in, first-out ("FIFO") or average method.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are carried at cost, net of accumulated depreciation. Cost includes expenditures for improvements and betterments that extend the useful lives of the assets and interest capitalized on significant capital projects. Interest expense is capitalized for qualifying assets under construction. Capitalized interest costs are included in property, plant and equipment and are depreciated over the useful life of the related asset. Capitalized interest was $79, $197 and $164 for the years ended December 31, 2025, 2024 and 2023, respectively. Repair and maintenance costs are charged to operations as incurred. Gains and losses on the disposal or retirement of property, plant and equipment are reflected in the statement of operations when the assets are sold or retired. The accounting guidance for asset retirement obligations requires the recording of liabilities equal to the fair value of asset retirement obligations and corresponding additional asset costs, when there is a legal asset retirement obligation as a result of existing or enacted law, statute or contract. The Partnership has conditional asset retirement obligations for the removal and disposal of hazardous materials from certain of the Partnership's manufacturing facilities. However, no asset retirement obligations have been recognized because the fair value of the conditional legal obligation cannot be measured due to the indeterminate settlement date of the obligation.
Impairment Of Long-Lived Assets and Intangible Assets	Impairment of Long-Lived Assets The accounting guidance for the impairment or disposal of long-lived assets requires that the Partnership assess long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable, including when negative conditions such as significant current or projected operating losses exist. Other factors considered by the Partnership when determining if an impairment assessment is necessary include, but are not limited to, significant changes or projected changes in supply and demand fundamentals (which would have a negative impact on operating rates or margins), new technological developments, new competitors with significant raw material or other cost advantages, adverse changes associated with the United States and world economies and uncertainties associated with governmental actions. Long-lived assets assessed for impairment are grouped by asset group, the lowest level for which identifiable cash flows are largely independent of the cash flows of other groups of assets and liabilities. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future net undiscounted cash flows expected to be generated by the asset group. Assets are considered to be impaired if the carrying amount of an asset exceeds the future undiscounted cash flows. The impairment recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or estimated fair value less costs to sell. Impairment of Goodwill The accounting guidance requires that goodwill be tested for impairment at least annually, or when events or changes in circumstances indicate the fair value of a reporting unit with goodwill has been reduced below its carrying amount. The impairment test for the recorded goodwill was performed in the fourth quarter of 2025 and did not indicate impairment of the goodwill. As of December 31, 2025, the Partnership's recorded goodwill was $5,814. See Note 6 for more information on the Partnership's annual goodwill impairment test.
Turnaround Costs	Turnaround Costs The Partnership accounts for turnaround costs under the deferral method. Turnarounds are the scheduled and required shutdowns of specific operating units in order to perform planned major maintenance activities. The costs related to the significant overhaul and refurbishment activities include maintenance materials, parts and direct labor costs. The costs of the turnaround are deferred when incurred at the time of the turnaround and amortized (within depreciation and amortization) on a straight-line basis until the next planned turnaround, which typically ranges from five to eight years. Deferred turnaround costs are presented as a component of deferred charges and other assets, net. The cash outflows related to these costs are included in operating activities in the consolidated statement of cash flows.
Concentration Of Credit Risk	Concentration of Credit Risk Financial instruments which potentially subject the Partnership to concentration of risk consist principally of trade receivables from third-party customers who purchase ethylene and ethylene co-products. The Partnership performs periodic credit evaluations, as applicable, of the customers' financial condition and generally does not require collateral. The Partnership maintains allowances for potential losses, as applicable.
Revenue Recognition	Revenue Recognition Revenue is recognized when OpCo transfers control of inventories to customers. Amounts recognized as revenues reflect the consideration to which OpCo expects to be entitled in exchange for those inventories. The Partnership and OpCo incorporate production volume and production cost forecasts in the estimated transaction prices from sales to Westlake under the Ethylene Sales Agreement. The Partnership recognizes revenue and accounts receivable upon transferring control of inventories to its customers. Ethylene sold to Westlake under the Ethylene Sales Agreement is transferred to Westlake immediately after production and recognized in sales. Control of inventories sold to third parties generally transfers upon shipment to the customer. The Partnership excludes taxes collected on behalf of customers from the estimated contract price. Provisions for discounts, rebates and returns are incorporated in the estimate of variable consideration and reflected as reduction to revenue in the same period as the related sales. The Partnership does not disclose the value of unsatisfied performance obligations because its contracts with customers (1) have an original expected duration of one year or less or (2) have only variable consideration that is calculated based on market prices at a specified date and is allocated to wholly unsatisfied performance obligations. The Partnership generates a substantial majority of its revenue from sales to Westlake under the Ethylene Sales Agreement. The Ethylene Sales Agreement is intended to generate a long-term, fixed cash margin per pound. See Note 2 for a description of the terms of the Ethylene Sales Agreement. The Partnership's direct commodity price risk is limited to the sales to third parties. See the Partnership's consolidated statements of operations for the disaggregation of net sales to Westlake and net sales to third parties.
Transportation and Freight	Transportation and Freight Amounts billed to customers for freight and handling costs on outbound shipments are included in net sales in the consolidated statements of operations. Transportation and freight costs incurred by the Partnership on outbound shipments are included in cost of sales in the consolidated statements of operations.
Environmental Costs	Environmental Costs Environmental costs relating to current operations are expensed or capitalized, as appropriate, depending on whether such costs provide future economic benefits. Remediation liabilities are recognized when the costs are considered probable and can be reasonably estimated. Measurement of liabilities is based on currently enacted laws and regulations, existing technology and undiscounted site-specific costs. Environmental liabilities in connection with properties that are sold or closed are realized upon such sale or closure, to the extent they are probable and estimable and not previously reserved. Recognition of any joint and several liabilities is based upon the Partnership's best estimate of its final pro rata share of the liability.
Income Taxes	Income Taxes The Partnership is a limited partnership and is treated as a partnership for U.S. federal income tax purposes and, therefore, is not liable for entity-level federal income taxes. The Partnership is, however, subject to state and local income taxes. Deferred tax expense or benefit is the result of changes in the deferred tax assets and liabilities during the period. Valuation allowances are recorded against deferred tax assets when it is considered more likely than not that the deferred tax assets will not be realized on a separate tax return basis.
Use Of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.
Other Comprehensive Income	Other Comprehensive Income The Partnership has not reported consolidated statements of comprehensive income for the years ended December 31, 2025, 2024 and 2023 due to immateriality of the components of other comprehensive income.
Recent Issued Accounting Pronouncements and Recently Adopted Accounting Standards	Recently Issued Accounting Pronouncements Measurement of Credit Losses for Accounts Receivable and Contract Assets (ASU No. 2025-05) In July 2025, the Financial Accounting Standards Board ("FASB") issued an accounting standards update to add a practical expedient in developing reasonable and supportable forecasts as part of estimating expected credit losses. All entities may elect a practical expedient that assumes the current conditions as of the balance sheet date do not change for the remaining life of the asset. The amendments in this update are effective for annual reporting periods beginning after December 15, 2025 and interim reporting periods within those annual reporting periods, with early adoption permitted. Entities should apply the new guidance prospectively. The Partnership does not expect that this accounting standard, upon adoption, will have a material impact on the Partnership's consolidated financial statements. Disaggregation of Income Statement Expenses (ASU No. 2024-03) In November 2024, the FASB issued an accounting standards update requiring public entities to disclose, on an annual and interim basis, detailed information about the types of expenses in relevant expense captions presented on the face of the income statement, including amounts for inventory purchases, employee compensation, depreciation and amortization of intangible assets and a qualitative description for remaining amounts not separately disaggregated. Additionally, the update requires disclosure of total selling expenses, and in annual periods, an entity's definition of selling expenses. The amendments in this update are effective for annual reporting periods beginning after December 15, 2026, and interim periods beginning after December 15, 2027 and are to be applied either prospectively or retrospectively. Early adoption is permitted. The Partnership is currently evaluating the impact of the update on the disclosures in the Partnership's consolidated financial statements. Recently Adopted Accounting Standard Income Taxes (ASU No. 2023-09) In December 2023, the FASB issued an accounting standards update to enhance the transparency and decision-usefulness of income tax disclosures and to provide information to better assess how an entity's operations and related tax risks and tax planning and operational opportunities affect its tax rate and prospects for future cash flows. For public business entities, the amendments in this update are effective for annual periods beginning after December 15, 2024, with an early adoption permitted. The amendments should be applied prospectively; however, retrospective application is permitted. The Partnership adopted this accounting standard in the 2025 annual period and applied the standard prospectively. The adoption of this ASU resulted in additional income tax disclosures (see Note 14).

Insider Trading Policies and Procedures	12 Months Ended
Insider Trading Policies and Procedures	Dec. 31, 2025
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true

Related Party Transactions

12 Months Ended

Dec. 31, 2025

Related Party Transactions

Related party transactions between the Partnership, OpCo and Westlake are primarily based on agreements such as the Ethylene Sales Agreement, the Feedstock Supply Agreement, the Services and Secondment Agreement, Site Lease Agreements, the Omnibus Agreement, the Investment Management Agreement, the Exchange Agreement, the OpCo Partnership Agreement, the OpCo Revolver and the MLP Revolver. These agreements, discussed in detail in Notes 2 and 8, reflect the pervasive effect of the relationship with Westlake on the Partnership's operations and its consolidated financial statements. Pursuant to these agreements, the Partnership and OpCo regularly enter into transactions with Westlake. See below for descriptions and details of significant related party transactions.

Sales to Related Parties

OpCo sells ethylene to Westlake under the Ethylene Sales Agreement. Additionally, the Partnership and OpCo from time to time provide other services or products for which it charges Westlake a fee.

OpCo sells a significant portion of its ethylene production to Westlake. Sales to related parties were as follows:


	Year Ended December 31,
	2025		2024		2023
Net sales—Westlake	$	1,033,276	$	950,801	$	1,026,655

As of December 31, 2025, OpCo had an annual production deficiency under the Ethylene Sales Agreement for the full year 2025 primarily due to the Petro 1 turnaround extending into April 2025, which was later than the planned completion in March 2025. The total Buyer Deficiency Fee recognized by the Partnership during the twelve months ended December 31, 2025 was $5,835. The Buyer Deficiency Fee is measured periodically based upon the lower of the actual production deficiency at period end or the estimated annual production deficiency based upon OpCo's annual anticipated production. These periodic estimates are updated at the end of the year based on actual annual production. The Buyer Deficiency Fee is classified as a component of net sales—Westlake.

Cost of Sales from Related Parties

Charges for goods and services purchased by the Partnership and OpCo from Westlake and included in cost of sales relate primarily to feedstock purchased under the Feedstock Supply Agreement and services provided under the Services and Secondment Agreement.

A significant portion of the Partnership's inputs included in cost of sales are supplied by Westlake. Charges from related parties for significant inputs included in cost of sales were as follows:


	Year Ended December 31,
	2025		2024		2023
Feedstock purchased from Westlake and included in cost of sales	$	382,698	$	310,856	$	398,700
Other charges from Westlake and included in cost of sales	133,824		125,702		123,039

Services from Related Parties Included in Selling, General and Administrative Expenses

Charges for services purchased by the Partnership from Westlake and included in selling, general and administrative expenses primarily relate to services Westlake performs on behalf of the Partnership under the Omnibus Agreement, including the Partnership's finance, legal, information technology, human resources, communication, ethics and compliance and other administrative functions.

Charges from related parties included within selling, general and administrative expenses were as follows:


	Year Ended December 31,
	2025		2024		2023
Services received from Westlake and included in selling, general and administrative expenses	$	25,017	$	25,654	$	27,085

Goods and Services from Related Parties Capitalized as Assets

Charges for goods and services purchased by the Partnership and OpCo from Westlake which were capitalized as assets relate primarily to the services of Westlake employees under the Services and Secondment Agreement.

Charges from related parties for goods and services capitalized as assets were as follows:


	Year Ended December 31,
	2025		2024		2023
Goods and services purchased from Westlake and capitalized as assets	$	7,311	$	2,295	$	3,660

Receivable under the Investment Management Agreement

On August 1, 2017, the Partnership, OpCo and Westlake executed an investment management agreement (the "Investment Management Agreement") that authorized Westlake to invest the Partnership's and OpCo's excess cash with Westlake for durations of up to a maximum of nine months. Per the terms of the Investment Management Agreement, the Partnership earns a market return plus five basis points and Westlake provides daily availability of the invested cash to meet any liquidity needs of the Partnership or OpCo. Accrued interest of $206 and $1,385 was included in the receivable under the Investment Management Agreement balance at December 31, 2025 and 2024, respectively. Total interest earned related to the Investment Management Agreement was $2,539, $5,364 and $4,424 for the years ended December 31, 2025, 2024 and 2023, respectively.

The Partnership's receivable under the Investment Management Agreement was as follows:


	December 31,
	2025		2024
Receivable under the Investment Management Agreement	$	23,378	$	134,557

Accounts Receivable from Related Parties

The Partnership's accounts receivable from Westlake result primarily from ethylene sales to Westlake and any Buyer Deficiency Fee and Shortfall recognized under the Ethylene Sales Agreement.

The Buyer Deficiency Fee of $5,835, as discussed above under "Sales to Related Parties" recognized in the twelve months ended December 31, 2025, was received by the Partnership in January 2026.

As a result of the Partnership's decision to postpone the maintenance turnaround at the Petro 1 facility from the third quarter of 2024 to the first quarter of 2025, OpCo's production resulted in "excess quantities" of ethylene for the contract year ended December 31, 2024. Pursuant to the terms of the Ethylene Sales Agreement, the excess quantities produced were sold to Westlake at prices that excluded certain non-variable costs of production. As of December 31, 2024, accounts receivable included sales associated with the excess quantities, which were at a lower sales price.

The Partnership's accounts receivable from Westlake were as follows:


	December 31,
	2025		2024
Accounts receivable—Westlake	$	63,571	$	31,975

Accounts Payable to Related Parties

The Partnership's accounts payable to Westlake result primarily from feedstock purchases under the Feedstock Supply Agreement and services provided under the Services and Secondment Agreement and the Omnibus Agreement.

The Partnership's accounts payable to Westlake were as follows:


	December 31,
	2025		2024
Accounts payable—Westlake	$	19,132	$	20,744

Debt Payable to Related Parties

See Note 8 for a description of related party debt payable balances.

Interest on related party debt payable balances, net of capitalized interest, for the years ended December 31, 2025, 2024 and 2023 was $22,899, $25,701 and $26,501, respectively. Interest on related party debt payable is presented as interest expense—Westlake in the consolidated statements of operations. At December 31, 2025 and 2024, accrued interest on related party debt was $5,508 and $5,848, respectively, and is reflected as a component of accrued and other liabilities in the consolidated balance sheets.

Debt payable to related parties was as follows:


	December 31,
	2025		2024
Long-term debt payable to Westlake	$	399,674	$	399,674

Related Party Leases

OpCo is obligated to Westlake under various long-term and short-term noncancelable operating leases, primarily related to rail cars and land. Operating lease rentals paid to Westlake for such leases were $1,705, $1,843 and $1,869 for the years ended December 31, 2025, 2024 and 2023, respectively, and are reflected in other charges from Westlake that are included in cost of sales.

OpCo has two site lease agreements with Westlake, each of which has a term of 50 years. Pursuant to the site lease agreements, OpCo pays Westlake one dollar per site per year.

Major Customer and Concentration of Credit Risk

During the years ended December 31, 2025, 2024 and 2023, Westlake accounted for approximately 88.6%, 83.7% and 86.2%, respectively, of the Partnership's net sales.

General

During the years ended December 31, 2025, 2024 and 2023, the Partnership reimbursed $333, $351 and $347, respectively, to Westlake for certain state tax payments.

Other

See Note 10 above for an additional transaction through which a related party acquired common units in a private placement.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483326/850-10-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
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-URI https://asc.fasb.org/1943274/2147480990/946-20-50-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
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+ Details

Cybersecurity Risk Management and Strategy Disclosure	12 Months Ended
Cybersecurity Risk Management and Strategy Disclosure	Dec. 31, 2025
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	OpCo has entered into the Services and Secondment Agreement with Westlake and we, OpCo and Westlake have entered into the Omnibus Agreement. Pursuant to these Agreements, Westlake performs various services for us, including those related to cybersecurity. As such, this disclosure addresses our cybersecurity policies and practices, some of which are executed by Westlake under the Services and Secondment Agreement and the Omnibus Agreement. With Westlake's support, we maintain a comprehensive approach to cybersecurity and data protection, based on a risk-based, defense-in-depth strategy. Westlake follows industry standard cybersecurity frameworks, including the National Institute of Standards and Technology Cybersecurity Framework to design, assess and update our cybersecurity strategy, controls and processes. Westlake regularly assesses industry best practices and standards and endeavors to implement them in its efforts to manage cybersecurity risk for us. The focus is on protecting our highest-value information assets, which include manufacturing systems, financial systems, and confidential, personal, and private information. To safeguard our networks and systems, Westlake has a dedicated cybersecurity organization overseen by its Senior Director, Cybersecurity and Network Operations, which operates within its information technology department overseen by its Chief Information Officer. Westlake's cybersecurity organization employs multiple security controls, such as firewalls, spam protection, web filtering, endpoint detection and response software, controlled access, vulnerability management, redundancies, patching, and regular onsite and offsite backups. Westlake's cybersecurity organization also uses a variety of processes to address cybersecurity threats related to the use of third-party technology and services, including pre-acquisition diligence, imposition of contractual obligations, and risk-based performance monitoring. Both Westlake's Chief Information Officer and its Senior Director, Cybersecurity and Network Operations have extensive experience in assessing and managing cybersecurity risks, including through decades of collective experience in information technology and cybersecurity roles of increasing responsibility both at Westlake and in prior positions. Westlake prioritizes cybersecurity awareness among employees and contractors through various training exercises, including formal programs and simulated phishing events. Westlake maintains incident response plans, playbooks, and engages third-party cybersecurity firms for simulated cyberattacks and penetration testing to identify potential risks. Westlake also has a third-party cybersecurity firm on retainer for incident assistance and response. Periodic internal self-assessments are conducted by Westlake's cybersecurity organization using the National Institute of Standards and Technology Cybersecurity Framework. From time to time, we and OpCo experience cybersecurity threats and attempted breaches and other incidents. Westlake classifies and tracks these events based on significance and implements remediation actions that it considers appropriate to address the risks to the Partnership and OpCo relating to such incidents. Although we and OpCo have not experienced material impacts to our business strategy, results of operations or financial condition from any such incidents in the past three years, we cannot guarantee that a material incident will not occur in the future. See "Item 1A. Risk Factors—Failure to adequately protect critical data and technology systems could materially affect our operations."
Cybersecurity Risk Management Processes Integrated [Flag]	true
Cybersecurity Risk Management Processes Integrated [Text Block]	With Westlake's support, we maintain a comprehensive approach to cybersecurity and data protection, based on a risk-based, defense-in-depth strategy. Westlake follows industry standard cybersecurity frameworks, including the National Institute of Standards and Technology Cybersecurity Framework to design, assess and update our cybersecurity strategy, controls and processes. Westlake regularly assesses industry best practices and standards and endeavors to implement them in its efforts to manage cybersecurity risk for us. The focus is on protecting our highest-value information assets, which include manufacturing systems, financial systems, and confidential, personal, and private information.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Board of Directors Oversight [Text Block]	The board of directors has authorized and approved our entry into the Services and Secondment Agreement and the Omnibus Agreement with Westlake, and has thereby charged Westlake's Corporate Risk and Sustainability Committee with assisting the board of directors with its oversight of cybersecurity risks, which is a component of our overall enterprise risk management program. As a result, Westlake's Corporate Risk and Sustainability Committee assists with the oversight of our cybersecurity risks. Westlake's Corporate Risk and Sustainability Committee includes directors with cybersecurity experience and expertise through supervision of information technology departments as executive officers. The board of directors also receives regular updates from Westlake's Chief Information Officer on cybersecurity risks, incidents and trends, and ongoing and planned projects impacting the Partnership and OpCo. Westlake's Chief Information Officer and our senior management receive regular status reports on the Partnership's and OpCo's cybersecurity risks from Westlake's cybersecurity organization. Further, incident updates are reported to our senior management and the board of directors as Westlake's Chief Information Officer and cybersecurity organization consider appropriate, depending on the severity of the incident.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	As a result, Westlake's Corporate Risk and Sustainability Committee assists with the oversight of our cybersecurity risks. Westlake's Corporate Risk and Sustainability Committee includes directors with cybersecurity experience and expertise through supervision of information technology departments as executive officers.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	As a result, Westlake's Corporate Risk and Sustainability Committee assists with the oversight of our cybersecurity risks. Westlake's Corporate Risk and Sustainability Committee includes directors with cybersecurity experience and expertise through supervision of information technology departments as executive officers. The board of directors also receives regular updates from Westlake's Chief Information Officer on cybersecurity risks, incidents and trends, and ongoing and planned projects impacting the Partnership and OpCo.
Cybersecurity Risk Role of Management [Text Block]	The board of directors also receives regular updates from Westlake's Chief Information Officer on cybersecurity risks, incidents and trends, and ongoing and planned projects impacting the Partnership and OpCo. Westlake's Chief Information Officer and our senior management receive regular status reports on the Partnership's and OpCo's cybersecurity risks from Westlake's cybersecurity organization. Further, incident updates are reported to our senior management and the board of directors as Westlake's Chief Information Officer and cybersecurity organization consider appropriate, depending on the severity of the incident. As part of our incident response planning, Westlake also maintains cross-functional response teams involving personnel outside of its cybersecurity organization, both globally and regionally, in order to be prepared to respond to an incident.
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	To safeguard our networks and systems, Westlake has a dedicated cybersecurity organization overseen by its Senior Director, Cybersecurity and Network Operations, which operates within its information technology department overseen by its Chief Information Officer.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	Both Westlake's Chief Information Officer and its Senior Director, Cybersecurity and Network Operations have extensive experience in assessing and managing cybersecurity risks, including through decades of collective experience in information technology and cybersecurity roles of increasing responsibility both at Westlake and in prior positions.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	Westlake's Chief Information Officer and our senior management receive regular status reports on the Partnership's and OpCo's cybersecurity risks from Westlake's cybersecurity organization. Further, incident updates are reported to our senior management and the board of directors as Westlake's Chief Information Officer and cybersecurity organization consider appropriate, depending on the severity of the incident.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Total net sales	$ 1,166,695	$ 1,135,896	$ 1,190,791
Cost of sales	818,847	716,957	803,332
Gross profit	347,848	418,939	387,459
Selling, general and administrative expenses	28,271	28,495	29,751
Income from operations	319,577	390,444	357,708
Other income (expense)
Interest expense—Westlake	(22,899)	(25,701)	(26,501)
Other income, net	2,445	5,251	4,232
Income before income taxes	299,123	369,994	335,439
Provision for income taxes	547	835	813
Net income	298,576	369,159	334,626
Less: Net income attributable to noncontrolling interest in OpCo	249,878	306,767	280,343
Net income attributable to Westlake Chemical Partners LP and limited partners' interest in net income	$ 48,698	$ 62,392	$ 54,283
Net income per limited partner unit attributable to Westlake Chemical Partners LP (basic and diluted)
Weighted average limited partner units outstanding (basic and diluted)	35,241,505	35,232,870	35,224,340
Affiliated Entity
Net co-products, ethylene and other sales—third parties	$ 1,033,276	$ 950,801	$ 1,026,655
Nonrelated Party
Net co-products, ethylene and other sales—third parties	133,419	185,095	164,136
Westlake \| Affiliated Entity
Selling, general and administrative expenses	25,017	25,654	27,085
Other income (expense)
Interest expense—Westlake	(22,899)	(25,701)	(26,501)
Common units
Other income (expense)
Net income attributable to Westlake Chemical Partners LP and limited partners' interest in net income	$ 48,698	$ 62,392	$ 54,283
Net income per limited partner unit attributable to Westlake Chemical Partners LP (basic and diluted)
Common units	$ 1.38	$ 1.77	$ 1.54
Diluted units	$ 1.38	$ 1.77	$ 1.54
Weighted average limited partner units outstanding (basic and diluted)	35,241,505	35,232,870	35,224,340
Common units \| Publicly and Privately Held
Net income per limited partner unit attributable to Westlake Chemical Partners LP (basic and diluted)
Weighted average limited partner units outstanding (basic and diluted)	21,119,275	21,110,640	21,102,110
Common units \| Westlake
Net income per limited partner unit attributable to Westlake Chemical Partners LP (basic and diluted)
Weighted average limited partner units outstanding (basic and diluted)	14,122,230	14,122,230	14,122,230

Deferred Charges and Other Assets (Tables)

12 Months Ended

Dec. 31, 2025

Other Assets [Abstract]

Schedule of Other Assets

Deferred charges and other assets, net consist of the following:


	December 31,
	2025		2024
Turnaround costs, net	$	213,953	$	129,565
Other	7,248		8,063
Deferred charges and other assets, net	$	221,201	$	137,628

Supplemental Information (Accrued Liabilities and Other Income, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Accrued Liabilities
Accrued and other liabilities	$ 22,199	$ 16,920
Accrued maintenance expense	2,764	1,458
Accrued interest	6,372	933
Affiliated Entity
Accrued Liabilities
Accrued interest	$ 5,508	$ 5,848

Related Party Transactions (Sales to Related Parties) (Details) - Affiliated Entity - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Related Party Transaction [Line Items]
Net sales	$ 1,033,276	$ 950,801	$ 1,026,655
Buyer deficiency fee	$ 5,835

- Definition

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.

+ References

+ Details

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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+ Details

Income Taxes (Schedule Of The Provision For (Benefit From) Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Current
State and local	$ 548	$ 921	$ 837
Deferred
State and local	(1)	(86)	(24)
Total provision	$ 547	$ 835	$ 813

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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+ Details

Income Taxes

12 Months Ended

Dec. 31, 2025

Income Tax Disclosure [Abstract]

Income Taxes

The components of income tax of the Partnership are as follows:


	Year Ended December 31,
	2025		2024		2023
Current

State and local	$	548	$	921	$	837

Deferred

State and local	(1)		(86)		(24)

Total provision	$	547	$	835	$	813

The Partnership adopted ASU 2023-09 in the 2025 period and applied this standard prospectively. The adoption of this ASU resulted in additional income tax disclosures. The reconciliation of income tax expense at the U.S. statutory rate to the income tax expense is as follows:


	Year Ended December 31,
	2025
	Amount		Percentage
Provision for federal income tax, at statutory rate	$	62,816	21.0	%
State income tax provision, net of federal income tax effect (1)	547		0.2	%
Partnership income not subject to entity-level federal income tax	(62,816)		(21.0)	%
Total provision	$	547	0.2	%

____________________________

(1) State income taxes in Kentucky and Texas made up the majority (greater than 50 percent) of the tax effect in this category.

The comparative periods are presented under the previous guidance within Accounting Standards Codification 740. The reconciliation of income tax expense at the U.S. statutory rate to the income tax expense is as follows:



	Year Ended December 31,
	2024		2023
Provision for federal income tax, at statutory rate	$	77,699	$	70,442
State income tax provision, net of federal income tax effect	835		813
Partnership income not subject to entity-level federal income tax	(77,699)		(70,442)
Total provision	$	835	$	813

The tax effects of the principal temporary differences between financial reporting and income tax reporting are as follows:


	December 31,
	2025		2024
Property, plant and equipment	$	(1,199)	$	(1,323)
Turnaround costs	(347)		(223)
Total deferred tax liabilities	$	(1,546)	$	(1,546)

Balance sheet classifications

Noncurrent deferred tax liability	$	(1,546)	$	(1,546)
Total deferred tax liabilities	$	(1,546)	$	(1,546)

- Definition

The entire disclosure for income tax.

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