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