3.25.1 html 109 168 1 false 39 0 false 7 false false R1.htm 0000001 - Document - Cover Sheet http://www.westlake.com/role/Cover Cover Cover 1 false false R2.htm 9952151 - Statement - Consolidated Balance Sheets Sheet http://www.westlake.com/role/ConsolidatedBalanceSheets Consolidated Balance Sheets Statements 2 false false R3.htm 9952152 - Statement - Consolidated Balance Sheets (Parenthetical) Sheet http://www.westlake.com/role/ConsolidatedBalanceSheetsParenthetical Consolidated Balance Sheets (Parenthetical) Statements 3 false false R4.htm 9952153 - Statement - Consolidated Statements of Operations Sheet http://www.westlake.com/role/ConsolidatedStatementsofOperations Consolidated Statements of Operations Statements 4 false false R5.htm 9952154 - Statement - Consolidated Statements of Changes in Equity Sheet http://www.westlake.com/role/ConsolidatedStatementsofChangesinEquity Consolidated Statements of Changes in Equity Statements 5 false false R6.htm 9952155 - Statement - Consolidated Statements of Cash Flows Sheet http://www.westlake.com/role/ConsolidatedStatementsofCashFlows Consolidated Statements of Cash Flows Statements 6 false false R7.htm 9952156 - Disclosure - Description of Business and Basis of Presentation Sheet http://www.westlake.com/role/DescriptionofBusinessandBasisofPresentation Description of Business and Basis of Presentation Notes 7 false false R8.htm 9952157 - Disclosure - Accounts Receivable???Third Parties Sheet http://www.westlake.com/role/AccountsReceivableThirdParties Accounts Receivable???Third Parties Notes 8 false false R9.htm 9952158 - Disclosure - Inventories Sheet http://www.westlake.com/role/Inventories Inventories Notes 9 false false R10.htm 9952159 - Disclosure - Property, Plant and Equipment Sheet http://www.westlake.com/role/PropertyPlantandEquipment Property, Plant and Equipment Notes 10 false false R11.htm 9952160 - Disclosure - Deferred Charges and Other Assets Sheet http://www.westlake.com/role/DeferredChargesandOtherAssets Deferred Charges and Other Assets Notes 11 false false R12.htm 9952161 - Disclosure - Distributions and Net Income Per Limited Partner Unit Sheet http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnit Distributions and Net Income Per Limited Partner Unit Notes 12 false false R13.htm 9952162 - Disclosure - Partners' Equity Sheet http://www.westlake.com/role/PartnersEquity Partners' Equity Notes 13 false false R14.htm 9952163 - Disclosure - Related Party Transactions Sheet http://www.westlake.com/role/RelatedPartyTransactions Related Party Transactions Notes 14 false false R15.htm 9952164 - Disclosure - Long-Term Debt Payable to Westlake Sheet http://www.westlake.com/role/LongTermDebtPayabletoWestlake Long-Term Debt Payable to Westlake Notes 15 false false R16.htm 9952165 - Disclosure - Fair Value Measurements Sheet http://www.westlake.com/role/FairValueMeasurements Fair Value Measurements Notes 16 false false R17.htm 9952166 - Disclosure - Supplemental Information Sheet http://www.westlake.com/role/SupplementalInformation Supplemental Information Notes 17 false false R18.htm 9952167 - Disclosure - Commitments and Contingencies Sheet http://www.westlake.com/role/CommitmentsandContingencies Commitments and Contingencies Notes 18 false false R19.htm 9952168 - Disclosure - Segment Information Sheet http://www.westlake.com/role/SegmentInformation Segment Information Notes 19 false false R20.htm 995410 - Disclosure - Pay vs Performance Disclosure Sheet http://xbrl.sec.gov/ecd/role/PvpDisclosure Pay vs Performance Disclosure Notes 20 false false R21.htm 995445 - Disclosure - Insider Trading Arrangements Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements Insider Trading Arrangements Notes 21 false false R22.htm 9955511 - Disclosure - Description of Business and Basis of Presentation (Policies) Sheet http://www.westlake.com/role/DescriptionofBusinessandBasisofPresentationPolicies Description of Business and Basis of Presentation (Policies) Policies 22 false false R23.htm 9955512 - Disclosure - Accounts Receivable???Third Parties (Tables) Sheet http://www.westlake.com/role/AccountsReceivableThirdPartiesTables Accounts Receivable???Third Parties (Tables) Tables http://www.westlake.com/role/AccountsReceivableThirdParties 23 false false R24.htm 9955513 - Disclosure - Inventories (Tables) Sheet http://www.westlake.com/role/InventoriesTables Inventories (Tables) Tables http://www.westlake.com/role/Inventories 24 false false R25.htm 9955514 - Disclosure - Distributions and Net Income Per Limited Partner Unit (Tables) Sheet http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitTables Distributions and Net Income Per Limited Partner Unit (Tables) Tables http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnit 25 false false R26.htm 9955515 - Disclosure - Related Party Transactions (Tables) Sheet http://www.westlake.com/role/RelatedPartyTransactionsTables Related Party Transactions (Tables) Tables http://www.westlake.com/role/RelatedPartyTransactions 26 false false R27.htm 9955516 - Disclosure - Long-Term Debt Payable to Westlake (Tables) Sheet http://www.westlake.com/role/LongTermDebtPayabletoWestlakeTables Long-Term Debt Payable to Westlake (Tables) Tables http://www.westlake.com/role/LongTermDebtPayabletoWestlake 27 false false R28.htm 9955517 - Disclosure - Fair Value Measurements (Tables) Sheet http://www.westlake.com/role/FairValueMeasurementsTables Fair Value Measurements (Tables) Tables http://www.westlake.com/role/FairValueMeasurements 28 false false R29.htm 9955518 - Disclosure - Segment Information (Tables) Sheet http://www.westlake.com/role/SegmentInformationTables Segment Information (Tables) Tables http://www.westlake.com/role/SegmentInformation 29 false false R30.htm 9955519 - Disclosure - Description of Business and Basis of Presentation (Details) Sheet http://www.westlake.com/role/DescriptionofBusinessandBasisofPresentationDetails Description of Business and Basis of Presentation (Details) Details http://www.westlake.com/role/DescriptionofBusinessandBasisofPresentationPolicies 30 false false R31.htm 9955520 - Disclosure - Accounts Receivable???Third Parties (Schedule Of Accounts Receivable) (Details) Sheet http://www.westlake.com/role/AccountsReceivableThirdPartiesScheduleOfAccountsReceivableDetails Accounts Receivable???Third Parties (Schedule Of Accounts Receivable) (Details) Details http://www.westlake.com/role/AccountsReceivableThirdPartiesTables 31 false false R32.htm 9955521 - Disclosure - Inventories (Details) Sheet http://www.westlake.com/role/InventoriesDetails Inventories (Details) Details http://www.westlake.com/role/InventoriesTables 32 false false R33.htm 9955522 - Disclosure - Property, Plant and Equipment (Detail) Sheet http://www.westlake.com/role/PropertyPlantandEquipmentDetail Property, Plant and Equipment (Detail) Details http://www.westlake.com/role/PropertyPlantandEquipment 33 false false R34.htm 9955523 - Disclosure - Deferred Charges and Other Assets (Details) Sheet http://www.westlake.com/role/DeferredChargesandOtherAssetsDetails Deferred Charges and Other Assets (Details) Details http://www.westlake.com/role/DeferredChargesandOtherAssets 34 false false R35.htm 9955524 - Disclosure - Distributions and Net Income Per Limited Partner Unit (Basic and Diluted Income Per Limited Partner Unit) (Details) Sheet http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitBasicandDilutedIncomePerLimitedPartnerUnitDetails Distributions and Net Income Per Limited Partner Unit (Basic and Diluted Income Per Limited Partner Unit) (Details) Details http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitTables 35 false false R36.htm 9955525 - Disclosure - Distributions and Net Income Per Limited Partner Unit (Distributions Declared) (Details) Sheet http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitDistributionsDeclaredDetails Distributions and Net Income Per Limited Partner Unit (Distributions Declared) (Details) Details http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitTables 36 false false R37.htm 9955526 - Disclosure - Distributions and Net Income Per Limited Partner Unit (Distribution Per Common Unit) (Details) Sheet http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitDistributionPerCommonUnitDetails Distributions and Net Income Per Limited Partner Unit (Distribution Per Common Unit) (Details) Details http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitTables 37 false false R38.htm 9955527 - Disclosure - Partners' Equity (Details) Sheet http://www.westlake.com/role/PartnersEquityDetails Partners' Equity (Details) Details http://www.westlake.com/role/PartnersEquity 38 false false R39.htm 9955528 - Disclosure - Related Party Transactions (Sales to Related Parties) (Details) Sheet http://www.westlake.com/role/RelatedPartyTransactionsSalestoRelatedPartiesDetails Related Party Transactions (Sales to Related Parties) (Details) Details http://www.westlake.com/role/RelatedPartyTransactionsTables 39 false false R40.htm 9955529 - Disclosure - Related Party Transactions (Cost of Sales from Related Parties) (Details) Sheet http://www.westlake.com/role/RelatedPartyTransactionsCostofSalesfromRelatedPartiesDetails Related Party Transactions (Cost of Sales from Related Parties) (Details) Details http://www.westlake.com/role/RelatedPartyTransactionsTables 40 false false R41.htm 9955530 - Disclosure - Related Party Transactions (Services from Related Parties Included in SG&A Expenses) (Details) Sheet http://www.westlake.com/role/RelatedPartyTransactionsServicesfromRelatedPartiesIncludedinSGAExpensesDetails Related Party Transactions (Services from Related Parties Included in SG&A Expenses) (Details) Details http://www.westlake.com/role/RelatedPartyTransactionsTables 41 false false R42.htm 9955531 - Disclosure - Related Party Transactions (Goods and Services Purchased from Westlake and Capitalized as Assets) (Details) Sheet http://www.westlake.com/role/RelatedPartyTransactionsGoodsandServicesPurchasedfromWestlakeandCapitalizedasAssetsDetails Related Party Transactions (Goods and Services Purchased from Westlake and Capitalized as Assets) (Details) Details http://www.westlake.com/role/RelatedPartyTransactionsTables 42 false false R43.htm 9955532 - Disclosure - Related Party Transactions (Accounts Receivable from and Accounts Payable to Related Parties) (Details) Sheet http://www.westlake.com/role/RelatedPartyTransactionsAccountsReceivablefromandAccountsPayabletoRelatedPartiesDetails Related Party Transactions (Accounts Receivable from and Accounts Payable to Related Parties) (Details) Details http://www.westlake.com/role/RelatedPartyTransactionsTables 43 false false R44.htm 9955533 - Disclosure - Related Party Transactions (General) (Details) Sheet http://www.westlake.com/role/RelatedPartyTransactionsGeneralDetails Related Party Transactions (General) (Details) Details http://www.westlake.com/role/RelatedPartyTransactionsTables 44 false false R45.htm 9955534 - Disclosure - Related Party Transactions (Debt Payable to Related Parties) (Details) Sheet http://www.westlake.com/role/RelatedPartyTransactionsDebtPayabletoRelatedPartiesDetails Related Party Transactions (Debt Payable to Related Parties) (Details) Details http://www.westlake.com/role/RelatedPartyTransactionsTables 45 false false R46.htm 9955535 - Disclosure - Related Party Transactions (Major Customer and Concentration Risk) (Details) Sheet http://www.westlake.com/role/RelatedPartyTransactionsMajorCustomerandConcentrationRiskDetails Related Party Transactions (Major Customer and Concentration Risk) (Details) Details http://www.westlake.com/role/RelatedPartyTransactionsTables 46 false false R47.htm 9955536 - Disclosure - Long-Term Debt Payable to Westlake (Details) Sheet http://www.westlake.com/role/LongTermDebtPayabletoWestlakeDetails Long-Term Debt Payable to Westlake (Details) Details http://www.westlake.com/role/LongTermDebtPayabletoWestlakeTables 47 false false R48.htm 9955537 - Disclosure - Fair Value Measurements (Summary of Carrying and Fair Values of Long Term Debt) (Details) Sheet http://www.westlake.com/role/FairValueMeasurementsSummaryofCarryingandFairValuesofLongTermDebtDetails Fair Value Measurements (Summary of Carrying and Fair Values of Long Term Debt) (Details) Details http://www.westlake.com/role/FairValueMeasurementsTables 48 false false R49.htm 9955538 - Disclosure - Supplemental Information (Details) Sheet http://www.westlake.com/role/SupplementalInformationDetails Supplemental Information (Details) Details http://www.westlake.com/role/SupplementalInformation 49 false false R50.htm 9955539 - Disclosure - Segment Information (Details) Sheet http://www.westlake.com/role/SegmentInformationDetails Segment Information (Details) Details http://www.westlake.com/role/SegmentInformationTables 50 false false All Reports Book All Reports wlkp-20250331.htm wlkp-20250331.xsd wlkp-20250331_cal.xml wlkp-20250331_def.xml wlkp-20250331_lab.xml wlkp-20250331_pre.xml http://fasb.org/us-gaap/2024 http://xbrl.sec.gov/dei/2024 http://xbrl.sec.gov/ecd/2024 true true