Limited Partners' Capital Account by Class [Axis] Limited Partners' Capital Account by Class [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Award Timing Predetermined Award Timing Predetermined [Flag] Related Party Transaction [Axis] Related Party Transaction [Axis] Weighted average interest rate Long-Term Debt, Weighted Average Interest Rate, at Point in Time Feedstock Purchased Feedstock Purchased [Member] Feedstock Purchased [Member] Entity File Number Entity File Number Tabular List, Table Tabular List [Table Text Block] Net income per limited partner unit: Earnings Per Share, Basic [Abstract] Supplemental Information Additional Financial Information Disclosure [Text Block] Recently Issued Accounting Pronouncement and Recently Adopted Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Schedule of Related Party Transactions Schedule of Related Party Transactions [Table Text Block] Accounts payable—third parties Increase (Decrease) in Accounts Payable Summary Of Carrying And Fair Values Of Long-Term Debt Fair Value, by Balance Sheet Grouping [Table Text Block] Majority-Owned Subsidiary, Unconsolidated Majority-Owned Subsidiary, Nonconsolidated [Member] Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Adjustment to Compensation: Adjustment to Compensation [Axis] Interest earned related to the IMA Interest earned related to the IMA Interest earned related to the IMA Related Party Transactions Related Party Transactions Disclosure [Text Block] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Schedule of Stock by Class [Table] Stock, Class of Stock [Table] Schedule of Segment Reporting Information, by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Inventory Disclosure [Abstract] Inventory Disclosure [Abstract] Incentive Distribution, Recipient [Domain] Incentive Distribution, Recipient [Domain] Adjustment to Compensation, Amount Adjustment to Compensation Amount Concentration risk percentage Concentration Risk, Percentage Affiliated Entity Affiliated Entity [Member] Accrued interest included in receivable under IMA Accrued interest included in receivable under IMA Accrued interest included in receivable under IMA Distribution Made to Limited Partner [Line Items] Distribution Made to Limited Partner [Line Items] Employee Stock Option Share-Based Payment Arrangement, Option [Member] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Insider Trading Policies and Procedures [Line Items] Site lease agreements, term (in years) Site lease agreements, term (in years) Site lease agreements, term (in years) Current assets Assets, Current [Abstract] Total liabilities and equity Liabilities and Equity Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Receivable under the Investment Management Agreement—Westlake Corporation ("Westlake") Receivables under Investment Management Agreements with Related Parties, Current Receivables under Investment Management Agreements with Related Parties, Current LIABILITIES Liabilities and Equity [Abstract] Cover [Abstract] Maximum Maximum [Member] Westlake Westlake Parent Company And Subsidiaries, Excluding Reporting Entity And Subsidiaries [Member] Parent Company and Subsidiaries, Excluding Reporting Entity and Subsidiaries [Member] Less: Net income attributable to noncontrolling interest in OpCo Net Income (Loss) Attributable to Noncontrolling Interest Concentration Risk Type [Domain] Concentration Risk Type [Domain] Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Loss from disposition of property, plant and equipment Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Pay vs Performance Disclosure [Line Items] Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Shell Company Entity Shell Company Other liabilities Other Liabilities, Noncurrent Operating Segments Operating Segments [Member] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Company Selected Measure Amount Company Selected Measure Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Name Measure Name Number of units sold in public offering (in shares) Partners' Capital Account, Units, Sold in Public Offering Other service charges Other Service Charges [Member] Other Service Charges [Member] Class of Stock [Line Items] Class of Stock [Line Items] Deferred income taxes Deferred Income Tax Liabilities, Net Document Fiscal Period Focus Document Fiscal Period Focus Award Timing Method Award Timing Method [Text Block] Distributions Made to Limited Partner [Table] Distributions Made to Limited Partner [Table] Award Type Award Type [Axis] Westlake Parent Company [Member] Legal Entity [Axis] Legal Entity [Axis] Total assets Assets Assets Trading Symbol Trading Symbol Total Westlake Chemical Partners LP partners' capital Partners' Capital Entity Address, City or Town Entity Address, City or Town Cash flows from operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Distributions per common unit (in usd per share) Distribution Made to Limited Partner, Distributions Paid, Per Unit Other segment items Segment Reporting, Other Segment Item, Amount Concentration Risk Type [Axis] Concentration Risk Type [Axis] Inventories Inventory Disclosure [Text Block] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] General Partner General Partner [Member] Entity Emerging Growth Company Entity Emerging Growth Company Entity Common Units, Units Outstanding Entity Common Stock, Shares Outstanding Right-of-use assets obtained in exchange for operating lease obligations Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] PEO PEO [Member] Accounts Receivable—Third Parties Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Investments with Westlake under the Investment Management Agreement Investments with Westlake under the Investment Management Agreement Investments with Westlake under the Investment Management Agreement Proceeds from debt payable to Westlake Proceeds from Related Party Debt Deferred charges and other assets, net Deferred Costs and Other Assets Weighted average limited partner units outstanding (basic and diluted) (in units) Weighted Average Number of Limited Partnership and General Partnership Unit Outstanding, Basic and Diluted Changes in operating assets and liabilities Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Units issued (in shares) Limited Partners' Capital Account, Units Issued Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Charges from related parties in cost of sales Related Parties Amount in Cost of Sales Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement [Abstract] Income Statement [Abstract] Provision for income taxes Income Tax Expense (Benefit) Basis spread on variable rate, percent Debt Instrument, Basis Spread on Variable Rate Accrued taxes Taxes Payable, Current Noncontrolling interest in Westlake Chemical OpCo LP ("OpCo") Noncontrolling Interest in Limited Partnerships Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Limited partner interest, additional ownership Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Additional Ownership Interest Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Additional Ownership Interest Customer Concentration Risk Customer Concentration Risk [Member] Net income Net income Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] City Area Code City Area Code Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] All Trading Arrangements All Trading Arrangements [Member] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Accrued and other liabilities Accrued Liabilities, Current Cash Distribution Cash Distribution [Member] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] MLP Revolver MLP Revolver [Member] MLP Revolver [Member] Cash flows from investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Net cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Related Party Transactions [Abstract] Related Party Transactions [Abstract] Subsequent Event Subsequent Event [Member] Goodwill Goodwill Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] PEO Total Compensation Amount PEO Total Compensation Amount Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Depreciation expense on property, plant and equipment Depreciation Equity Components [Axis] Equity Components [Axis] Goods and services purchased from Westlake and capitalized as assets Related Party Transaction Purchases From Related Party Capitalized As Assets Related Party Transaction Purchases From Related Party Capitalized As Assets Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Concentration Risk [Table] Concentration Risk [Table] Long-term debt payable to Westlake Other Long-Term Debt, Noncurrent Other Performance Measure, Amount Other Performance Measure, Amount Entity Address, State or Province Entity Address, State or Province IDR Holders IDR Holders [Member] Incentive Distribution Rights Holders [Member] Related Party [Domain] Related and Nonrelated Parties [Domain] Westlake Chemical OpCo LP Westlake Chemical OpCo LP [Member] Westlake Chemical OpCo LP [Member] Total current liabilities Liabilities, Current Individual: Individual [Axis] Above $1.2938 up to $1.4063 Cash Distribution, Tranche One [Member] Cash Distribution, Tranche One [Member] Managing Member or General Partner [Axis] Managing Member or General Partner [Axis] Entity [Domain] Entity [Domain] Amortization expense Amortization Net cash provided by (used for) investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Net income per limited partner unit attributable to Westlake Chemical Partners LP (basic and diluted) Earnings Per Unit [Abstract] Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Interest paid Interest Paid, Excluding Capitalized Interest, Operating Activity Document Fiscal Year Focus Document Fiscal Year Focus Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Units sold in secondary offering price per unit (in dollars per share) Partners' Capital Account, Units, Sold in Public Offering, Price per Unit Partners' Capital Account, Units, Sold in Public Offering, Price per Unit OpCo OpCo Segment [Member] OpCo Segment Entity Interactive Data Current Entity Interactive Data Current Net accounts receivable—Westlake Increase (Decrease) in Accounts Receivable, Related Parties Equity [Abstract] Equity [Abstract] Ethylene Sales Agreement Ethylene Sales Agreement [Member] Ethylene Sales Agreement Segment Information Segment Reporting Disclosure [Text Block] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Distributions Made to Limited Partner, by Distribution Distributions Made to Limited Partner, by Distribution [Table Text Block] Ownership [Domain] Ownership [Domain] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Selling, general and administrative expenses Selling, general and administrative expenses Selling, General and Administrative Expense Investee Investee [Member] Depreciation and amortization Depreciation, Depletion and Amortization Customer [Domain] Customer [Domain] Accrued interest on related party debt Interest Payable, Current Entity Central Index Key Entity Central Index Key PEO Name PEO Name Total net sales Revenues Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Finished products Inventory, Finished Goods, Gross Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Arrangement Duration Trading Arrangement Duration Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Segments [Axis] Segments [Axis] Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Exercise Price Award Exercise Price Entity Filer Category Entity Filer Category Limited Partner Limited Partner [Member] Local Phone Number Local Phone Number Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Trade customers Accounts Receivable, before Allowance for Credit Loss, Current Subsequent Event Type [Axis] Subsequent Event Type [Axis] Common unitholders Limited Partners' Capital Account Buyer deficiency fee Buyer deficiency fee Buyer deficiency fee Above $1.4063 up to $1.6875 Cash Distribution, Tranche Two [Member] Cash Distribution, Tranche Two [Member] ASSETS Assets [Abstract] Nonrelated Party Nonrelated Party [Member] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Balance Sheet Location [Axis] Statement of Financial Position Location, Balance [Axis] Debt Instrument [Axis] Debt Instrument [Axis] Fair Value Measurements Fair Value Disclosures [Text Block] EQUITY Equity, Attributable to Parent [Abstract] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Allowance for credit losses Accounts Receivable, Allowance for Credit Loss, Current Feedstock, additives and chemicals Inventory, Work in Process and Raw Materials Ownership [Axis] Ownership [Axis] Fair Value as of Grant Date Award Grant Date Fair Value Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Abstract] Entity Registrant Name Entity Registrant Name Purchase commitment, renewal term Long-Term Purchase Commitment, Renewal Term Long-Term Purchase Commitment, Renewal Term Schedule of Limited Partners' Capital Account by Class [Table] Partners' Capital, Limited Partner's Capital Account, Class [Table] Net income in excess of distribution (Distribution in excess of net income) Undistributed Earnings, Basic Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Document Quarterly Report Document Quarterly Report Westlake Chemical OpCo GP LLC Westlake Chemical OpCo GP LLC [Member] Westlake Chemical OpCo GP LLC [Member] Long-term debt payable to Westlake, fair value Long-Term Debt, Fair Value Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Counterparty Name [Domain] Counterparty Name [Domain] Number of operating segments Number of Operating Segments Distribution declared per unit (in usd per unit) Distribution Made to Limited Partner, Distributions Declared, Per Unit Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Related Party [Axis] Related and Nonrelated Parties [Axis] Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Marginal Percentage Interest in Distributions Incentive Distribution, Marginal Percentage Interest in Distributions Incentive Distribution, Marginal Percentage Interest in Distributions Restatement Determination Date: Restatement Determination Date [Axis] IMA, Partnership earned amount added to market rate, basis points IMA, Partnership earned amount added to market rate, basis points IMA, Partnership earned amount added to market rate, basis points Non-PEO NEO Non-PEO NEO [Member] Accounts Receivable Accounts Receivable [Member] Number of production facilities Number of Production Facilities Number of Production Facilities Accrued turnaround costs Accrued turnaround costs Accrued turnaround costs Name Trading Arrangement, Individual Name All Award Types Award Type [Domain] Units issued for vested phantom units Stock Issued During Period, Value, Other Equity Awards Adjustments Equity Awards Adjustments [Member] Other losses (gains), net Other Noncash Income (Expense) Raw material, energy, manufacturing and logistics costs Raw material, energy, manufacturing and logistics costs Raw material, energy, manufacturing and logistics costs Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Accounts receivable—third parties Increase (Decrease) in Accounts and Other Receivables Compensation Amount Outstanding Recovery Compensation Amount Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Senior Unsecured Revolving Credit Facility Senior Unsecured Revolving Credit Facility [Member] Senior Unsecured Revolving Credit Facility [Member] Above $1.6875 Cash Distribution, Tranche Three [Member] Cash Distribution, Tranche Three [Member] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Name Awards Close in Time to MNPI Disclosures, Individual Name Deferred Charges and Other Assets Other Assets Disclosure [Text Block] Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Distribution Type [Axis] Distribution Type [Axis] Distribution to unitholders Limited Partners' Capital Account, Distribution Amount Segments [Domain] Segments [Domain] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Balance Sheet Location [Domain] Statement of Financial Position Location, Balance [Domain] Inventories Increase (Decrease) in Inventories Inventories Inventories Inventory, Net Minimum Minimum [Member] Company Selected Measure Name Company Selected Measure Name Weighted average units outsanding: Earnings per Unit, Basic and Diluted, Other Disclosure [Abstract] Earnings per Unit, Basic and Diluted, Other Disclosure Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Accounts payable Accounts Payable, Current Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] All Executive Categories All Executive Categories [Member] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Distributions declared Distributed Earnings Other Assets, Noncurrent [Abstract] Other Assets, Noncurrent [Abstract] Commitments and contingencies (Note 12) Commitments and Contingencies Limited Partners' Capital Account, Class [Domain] Limited Partners' Capital Account, Class [Domain] Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Entity Small Business Entity Small Business Units outstanding (in shares) Limited Partners' Capital Account, Units Outstanding Noncontrolling Interest in OpCo Noncontrolling Interest [Member] Document Transition Report Document Transition Report Number of common carrier pipelines Number of Common Carrier Pipelines Number of Common Carrier Pipelines Underlying Securities Award Underlying Securities Amount Concentration Risk [Line Items] Concentration Risk [Line Items] Equity Component [Domain] Equity Component [Domain] Statement of Partners' Capital [Abstract] Statement of Partners' Capital [Abstract] Schedule of Incentive Distributions Made to Managing Members or General Partners by Distribution Schedule of Distributions [Table Text Block] Schedule of Distributions [Table Text Block] Document Period End Date Document Period End Date PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Document Type Document Type Distributions and Net Income Per Limited Partner Unit Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Net co-products, ethylene and other sales—third parties Revenue from Contract with Customer, Excluding Assessed Tax All Individuals All Individuals [Member] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Additions to property, plant and equipment Payments to Acquire Property, Plant, and Equipment Name Forgone Recovery, Individual Name Incentive distribution rights, target distribution per unit requiring marginal percentage distribution to IDR holders (in usd per share) Incentive Distribution Rights, Target Distribution Per Unit Requiring Marginal Percentage Distribution to IDR Holders Incentive Distribution Rights, Target Distribution Per Unit Requiring Marginal Percentage Distribution to IDR Holders Total current assets Assets, Current Statistical Measurement [Axis] Statistical Measurement [Axis] Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Accrued Liabilities Accrued Liabilities [Member] Common units (basic) (in usd per share) Basic (in usd per share) Net Income (Loss), Per Outstanding Limited Partnership Unit, Basic, Net of Tax Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Site lease agreement, number Site lease agreement, number Site lease agreement, number Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Current liabilities Liabilities, Current [Abstract] Amount paid to purchase additional limited partner interest Payments to Acquire Limited Partnership Interests Deferred charges and other assets and others, net Increase (Decrease) in Other Operating Assets and Liabilities, Net Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Partner Type of Partners' Capital Account, Name [Domain] Partner Type of Partners' Capital Account, Name [Domain] Common units Common units Common Units [Member] Common Units [Member] Accrued and other liabilities Increase (Decrease) in Accrued Liabilities Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Table] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Accounts receivable, net—Westlake Accounts Receivable, after Allowance for Credit Loss, Current Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Title of 12(b) Security Title of 12(b) Security Total equity Total equity Total equity Partners' Capital, Including Portion Attributable to Noncontrolling Interest Earnings Per Share [Abstract] Earnings Per Share [Abstract] Consolidation Items [Domain] Consolidation Items [Domain] Description of Business and Basis of Presentation Business Description and Basis of Presentation [Text Block] Other income, net Nonoperating Income (Expense) Maturities of investments with Westlake under the Investment Management Agreement Maturities of investments with Westlake under the Investment Management Agreement Maturities of investments with Westlake under the Investment Management Agreement Gross profit Gross Profit Distributions to unitholders Distribution Made to Limited Partner, Cash Distributions Paid Award Timing Disclosures [Line Items] Schedule Of Inventory Schedule of Inventory, Current [Table Text Block] Property, Plant and Equipment Property, Plant and Equipment Disclosure [Text Block] Partners' Equity Equity [Text Block] Partner Type [Axis] Partner Type [Axis] Distribution to noncontrolling interest retained in OpCo by Westlake Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Net income attributable to Westlake Chemical Partners LP and limited partners' interest in net income Net income Net Income (Loss) Attributable to Parent Subsequent Event [Table] Subsequent Event [Table] Expiration Date Trading Arrangement Expiration Date Property, plant and equipment, net Property, Plant and Equipment, Net Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Adoption Date Trading Arrangement Adoption Date Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Entity Current Reporting Status Entity Current Reporting Status Customer [Axis] Customer [Axis] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Income from operations Operating Income (Loss) Consolidated Entities [Domain] Consolidated Entities [Domain] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Executive Category: Executive Category [Axis] Subsequent distribution to IDR holders Incentive Distribution, Subsequent Distribution Amount Amount of incentive obligation earned in cash or stock during the period by the Partnership's incentive distribution rights holders and paid after the end of the accounting period. Limited Liability Company Limited Liability Company [Member] Limited partner interest Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest Current Fiscal Year End Date Current Fiscal Year End Date Subsequent Event Type [Domain] Subsequent Event Type [Domain] Site lease agreements, OpCo annual obligation to WLK Site lease agreements, annual proceeds per site Site lease agreements, annual proceeds per site Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Schedule of Accounts, Notes, Loans and Financing Receivable Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Statement [Table] Statement [Table] Adjustments to reconcile net income to net cash provided by operating activities Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Cash flows from financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Revenue Benchmark Revenue Benchmark [Member] Repayment of debt payable to Westlake Repayments of Related Party Debt Publicly and Privately Held Unidentified Third Parties [Member] Unidentified Third Parties [Member] Accounts Receivable, after Allowance for Credit Loss [Abstract] Accounts Receivable, after Allowance for Credit Loss [Abstract] Accounts receivable, net—third parties Accounts receivable, net—third parties Receivables, Net, Current All Adjustments to Compensation All Adjustments to Compensation [Member] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Amendment Flag Amendment Flag Termination Date Trading Arrangement Termination Date Net cash used for financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Unit Holders Unit Holders [Member] Unit Holders [Member] Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Accrued Liabilities [Abstract] Accrued Liabilities [Abstract] Measure: Measure [Axis] Cost of sales Cost of sales Cost of Product and Service Sold Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Related Party Transaction [Domain] Related Party Transaction [Domain] Subsequent Events [Abstract] Subsequent Events [Abstract] Segment Reporting [Abstract] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Operating lease expense Operating Lease, Expense Partners' capital account, units, sold to related party (in shares) Partners' Capital Account, Units, Sold to Related Party Partners' Capital Account, Units, Sold to Related Party Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Other income (expense) Nonoperating Income (Expense) [Abstract] Entity Tax Identification Number Entity Tax Identification Number Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Consolidated Entities [Axis] Consolidated Entities [Axis] Interest expense—Westlake Interest expense—Westlake Interest Expense, Nonoperating Trading Arrangement: Trading Arrangement [Axis] Total Shareholder Return Amount Total Shareholder Return Amount Common units, diluted (in usd per share) Net Income (Loss), Net of Tax, Per Outstanding Limited Partnership Unit, Diluted Subsequent Events Subsequent Events [Text Block] Insider Trading Arrangements [Line Items] Corporate Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] Security Exchange Name Security Exchange Name Long-Term Debt Payable to Westlake Related Party Transactions, Long-term Debt [Text Block] Related Party Transactions, Long-term Debt [Text Block] Total liabilities Liabilities Common And Subordinated Units Common And Subordinated Units [Member] Common And Subordinated Units [Member] Limited Partners' Capital Account [Line Items] Limited Partners' Capital Account [Line Items] Distributions to noncontrolling interest retained in OpCo by Westlake Payments of Ordinary Dividends, Noncontrolling Interest Capital expenditures incurred but not yet paid Capital Expenditures Incurred but Not yet Paid Related Party Transactions, Long-term Debt Related Party Transactions, Long-term Debt [Table Text Block] Related Party Transactions, Long-term Debt [Table Text Block] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Long-term debt payable to Westlake OpCo Revolver [Member] OpCo Revolver [Member] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Partners units, maximum aggregate offering amount, ATM Partners Units, Maximum Aggregate Offering Amount, ATM Partners Units, Maximum Aggregate Offering Amount, ATM Statement [Line Items] Statement [Line Items] Consolidation Items [Axis] Consolidation Items [Axis] Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Credit spread adjustment Debt Instrument, Credit Spread Adjustment Debt Instrument, Credit Spread Adjustment Cash and cash equivalents Cash and Cash Equivalent General partner—Westlake General Partners' Capital Account Counterparty Name [Axis] Counterparty Name [Axis] Subsequent Event [Line Items] Subsequent Event [Line Items] Distribution Type [Domain] Distribution Type [Domain] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Non-NEOs Non-NEOs [Member] Net increase (decrease) in cash and cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation