Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Affiliated Entity [Member] Affiliated Entity [Member] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Westlake [Member] Parent Company And Subsidiaries, Excluding Reporting Entity And Subsidiaries [Member] Parent Company and Subsidiaries, Excluding Reporting Entity and Subsidiaries [Member] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Predecessor [Member] Predecessor [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Net sales - Westlake Revenue from Related Parties Schedule of Related Party Transactions Schedule of Related Party Transactions [Table Text Block] Accounts Receivable, Net [Abstract] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Trade customers Accounts Receivable, Gross, Current Allowance for doubtful accounts Allowance for Doubtful Accounts Receivable, Current Receivables from trade customers and affiliates, net Trade Customer And Affiliate Receivable Net Current The aggregate of amounts due from customers or clients, within one year of the balance sheet date (or one operating cycle, if longer), for goods or services that have been delivered or sold in the normal course of business, and amounts due from related parties (affiliates) payable within one year of the balance sheet, reduced to their estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection. Other Other Receivables Current Amount due from other third-parties, or arising from transactions not separately disclosed, within one year of the balance sheet date (or the normal operating cycle, whichever is longer). Accounts receivable, net - third parties Receivables, Net, Current Other Assets [Abstract] Entities [Table] Entities [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other Assets [Member] Other Assets [Member] Entity Information [Line Items] Entity Information [Line Items] Amortization expense Amortization Statement of Partners' Capital [Abstract] Statement [Table] Statement [Table] Limited Partners' Capital Account by Class [Axis] Limited Partners' Capital Account by Class [Axis] Limited Partners' Capital Account, Class [Domain] Limited Partners' Capital Account, Class [Domain] Common units [Member] Common Units [Member] Common Units [Member] Subordinated units [Member] Subordinated Units [Member] Subordinated Units [Member] Public [Member] Unidentified Third Parties [Member] Unidentified Third Parties [Member] Partner Type [Axis] Partner Type [Axis] Partner Type of Partners' Capital Account, Name [Domain] Partner Type of Partners' Capital Account, Name [Domain] Limited Partner [Member] Limited Partner [Member] General Partner [Member] General Partner [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Noncontrolling Interest in OpCo [Member] Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Equity, beginning balance Partners' Capital, Including Portion Attributable to Noncontrolling Interest Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net distributions to Westlake Partners' Capital Account, Distributions Quarterly distributions to unitholders Limited Partners' Capital Account, Distribution Amount Quarterly distributions to noncontrolling interest retained in OpCo by Westlake Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Equity, ending balance Document Documentand Entity Information [Abstract] Document - Document and Entity Information [Abstract] Document Information [Table] Document Information [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Document Information [Line Items] Document Information [Line Items] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Property, Plant and Equipment [Abstract] Property, Plant and Equipment Property, Plant and Equipment Disclosure [Text Block] Risks and Uncertainties [Abstract] Concentration Risk [Table] Concentration Risk [Table] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Net sales [Member] Sales Revenue, Net [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Customer Concentration Risk [Member] Customer Concentration Risk [Member] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Concentration Risk [Line Items] Concentration Risk [Line Items] Concentration risk percentage Concentration Risk, Percentage Organization, Consolidation and Presentation of Financial Statements [Abstract] Interest incurred, added to principal on promissory notes outstanding Interest Incurred, Added to Debt Outstanding Interest Incurred, Added to Debt Outstanding Increase (reduction) in capital expenditure accrual Increase (Decrease) in Capital Expenditure Accrual Increase (Decrease) in Capital Expenditure Accrual Earnings Per Share [Abstract] Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Supplemental Information Additional Financial Information Disclosure [Text Block] Schedule of Limited Partners' Capital Account by Class [Table] Schedule of Limited Partners' Capital Account by Class [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Westlake Chemical OpCo LP [Member] Westlake Chemical OpCo LP [Member] Westlake Chemical OpCo LP [Member] Westlake Chemical OpCo GP LLC [Member] Westlake Chemical OpCo GP LLC [Member] Westlake Chemical OpCo GP LLC [Member] Limited Liability Company [Member] Limited Liability Company [Member] Majority-Owned Subsidiary, Unconsolidated [Member] Majority-Owned Subsidiary, Unconsolidated [Member] Limited Partners' Capital Account [Line Items] Limited Partners' Capital Account [Line Items] Amount paid to purchase additional limited partner interest Payments to Acquire Limited Partnership Interests Number of units sold in public offering Partners' Capital Account, Units, Sold in Public Offering Limited partner interest Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest Number of ethylene production facilities Number of Production Facilities Number of Production Facilities Limited Partners' Common Units [Member] Limited Partners' Subordinated Units [Member] Distribution declared Distributed Earnings Net income in excess of distribution Undistributed Earnings, Basic Net income attributable to Westlake Chemical Partners LP Net Income (Loss) Attributable to Parent Weighted average units outsanding: Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract] Basic and diluted (shares) Weighted Average Number of Shares Outstanding, Basic and Diluted Net income per limited partner unit: Earnings Per Share, Basic and Diluted [Abstract] Income per limited partner unit (usd per share) Earnings Per Share, Basic and Diluted Inventory Disclosure [Abstract] Inventories Inventory Disclosure [Text Block] Statement of Cash Flows [Abstract] Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Provision for doubtful accounts Provision for Doubtful Accounts Loss from disposition of fixed assets Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Deferred income taxes Deferred Income Tax Expense (Benefit) Income from equity method investment, net of dividends Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Changes in operating assets and liabilities Increase (Decrease) in Operating Capital [Abstract] Accounts receivable—third parties Increase (Decrease) in Accounts and Other Receivables Net accounts receivable—Westlake Increase (Decrease) in Accounts Receivable, Related Parties Inventories Increase (Decrease) in Inventories Prepaid expenses and other current assets Increase Decrease In Prepaid Expenses And Other Current Assets The increase (decrease) during the reporting period in the aggregate value of prepaid expenses and other current assets. Accounts payable Increase (Decrease) in Accounts Payable Accrued and other liabilities Increase (Decrease) in Accrued Liabilities Other, net Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Additions to property, plant and equipment Payments to Acquire Property, Plant, and Equipment Settlements of derivative instruments Payments for (Proceeds from) Derivative Instrument, Investing Activities Net cash used for investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from debt payable to Westlake Proceeds from Related Party Debt Repayment of debt payable to Westlake Repayments of Related Party Debt Quarterly distributions to noncontrolling interest retained in OpCo by Westlake Payments to Noncontrolling Interests Quarterly distributions to unitholders Distribution Made to Limited Partner, Cash Distributions Paid Net distributions to Westlake prior to initial public offering Payments of Distributions to Affiliates Net cash used for financing activities Net Cash Provided by (Used in) Financing Activities Net increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property, plant and equipment Property, Plant and Equipment, Net Depreciation expense on property, plant and equipment Depreciation Basis of Financial Statements Basis of Accounting, Policy [Policy Text Block] Goods and services purchased from Westlake and capitalized as assets RelatedPartyTransactionPurchasesFromRelatedPartyCapitalizedAsAssets Related Party Transaction Purchases From Related Party Capitalized As Assets Feedstock purchased from Westlake and included in cost of sales Related Parties Amount In Cost Of Sales, Feedstock Purchased Related Parties Amount In Cost Of Sales, Feedstock Purchased Other charges from Westlake and included in cost of sales Cost Of Goods Sold, Other Cost Of Goods Sold, Other Total Cost of Goods Sold Schedule Of Inventory Schedule of Inventory, Current [Table Text Block] Distributions Made to Limited Partner [Table] Distributions Made to Limited Partner [Table] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Distribution Made to Limited Partner [Line Items] Distribution Made to Limited Partner [Line Items] Distribution declared per unit Distribution Made to Limited Partner, Distributions Declared, Per Unit Distribution declared Distribution Made to Limited Partner, Cash Distributions Declared Investments, Debt and Equity Securities [Abstract] Schedule of Cash and Cash Equivalents [Table] Schedule of Cash and Cash Equivalents [Table] Investments by Category [Axis] Investments by Category [Axis] Marketable Securities and Investments Held at Cost [Domain] Marketable Securities and Investments Held at Cost [Domain] Held-to-maturity Securities [Member] Held-to-maturity Securities [Member] Cash and Cash Equivalents [Line Items] Cash and Cash Equivalents [Line Items] Cash and cash equivalents Cash Equivalents, at Carrying Value Accrued Liabilities [Member] Accrued Liabilities [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Other Nonoperating Income (Expense) [Member] Other Nonoperating Income (Expense) [Member] Interest on related party debt payable Interest Expense, Related Party Interest capitalized Interest Costs Capitalized Accrued interest on related party debt Interest Payable, Current Long-term debt payable to Westlake Due to Related Parties, Noncurrent Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Net Income Per Limited Partner Unit Earnings Per Share [Text Block] Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Current assets Assets, Current [Abstract] Cash and cash equivalents Accounts receivable, net—Westlake Chemical Corporation (Westlake) Accounts Receivable, Related Parties, Current Accounts receivable, net—third parties Inventories Inventory, Net Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current Property, plant and equipment, net Other assets, net Goodwill Goodwill Deferred charges and other assets, net Deferred Costs and Other Assets Total other assets, net Other Assets, Noncurrent Total assets Assets LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Current liabilities Liabilities, Current [Abstract] Accounts payable—Westlake Accounts Payable, Related Parties, Current Accounts payable—third parties Accounts Payable, Current Accrued liabilities Accrued Liabilities, Current Total current liabilities Liabilities, Current Deferred income taxes Deferred Tax Liabilities, Net, Noncurrent Other liabilities Other Liabilities, Noncurrent Total liabilities Liabilities Commitments and contingencies (Notes 9 and 14) Commitments and Contingencies EQUITY Stockholders' Equity Attributable to Parent [Abstract] Limited Partners' Capital Account Limited Partners' Capital Account General Partners' Capital Account General Partners' Capital Account Total Westlake Chemical Partners LP partners' capital Partners' Capital Noncontrolling interest in Westlake Chemical OpCo LP (OpCo) Noncontrolling Interest in Limited Partnerships Total equity Total liabilities and equity Liabilities and Equity Related Party Transactions Related Party Transactions Disclosure [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Services received from Westlake and included in selling, general and administrative expenses Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party Description of Business and Basis of Presentation Business Description and Basis of Presentation [Text Block] Other Assets Investments and Other Noncurrent Assets [Text Block] Income Statement [Abstract] Net co-product, ethylene and feedstock sales—third parties Other Revenue, Net Total net sales Revenue, Net Cost of sales Gross profit Gross Profit Selling, general and administrative expenses Selling, General and Administrative Expense Income from operations Operating Income (Loss) Other income (expense) Nonoperating Income (Expense) [Abstract] Interest expense—Westlake Other income, net Nonoperating Income (Expense) Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest (Benefit from) provision for income taxes Income Tax Expense (Benefit) Less: Net income attributable to noncontrolling interest in OpCo Net Income (Loss) Attributable to Noncontrolling Interest Net income attributable to Westlake Chemical Partners LP per limited partner unit (basic and diluted) Weighted average limited partner units outstanding (basic and diluted) Weighted average limited partner units outstanding (shares) Subsequent Event [Table] Subsequent Event [Table] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility [Member] Revolving Credit Facility [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Long-term debt payable to Westlake Related Party Transactions, Long-term Debt [Text Block] Related Party Transactions, Long-term Debt [Text Block] Schedule Of Accounts Receivable - Third Parties Schedule Of Accounts And Financing Receivables [Table Text Block] Tabular disclosure of the various categories of receivables, including trade and other receivables, and for each the gross carrying value, allowance (if appropriate), and net carrying value as of the balance sheet date. Accounts receivable, net—Westlake Accounts payable—Westlake Effective income tax rate Effective Income Tax Rate Reconciliation, Percent U.S. federal statutory income tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Units issued Limited Partners' Capital Account, Units Issued Units outstanding Limited Partners' Capital Account, Units Outstanding Major Customer and Concentration of Credit Risk Concentration Risk Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] 2013 Promissory Note [Member] Promissory Notes, 2013 [Member] Promissory Notes, 2013 [Member] OpCo Revolver [Member] OpCo Revolver [Member] OpCo Revolver [Member] MLP Revolver MLP Revolver [Member] MLP Revolver [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Senior Notes [Member] Senior Notes [Member] Senior Unsecured Revolving Credit Facility [Member] Senior Unsecured Revolving Credit Facility [Member] Senior Unsecured Revolving Credit Facility [Member] Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis] Measurement Basis [Axis] Fair Value, Disclosure Item Amounts [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying Value [Member] Reported Value Measurement [Member] Fair Value [Member] Estimate of Fair Value Measurement [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Senior Notes Senior Notes, Fair Value Disclosure This element represents the portion of the balance sheet assertion valued at fair value by the entity 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. This item represents senior notes as of the balance sheet date. Line of Credit [Member] Line of Credit [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Prime Rate [Member] Prime Rate [Member] LIBOR [Member] London Interbank Offered Rate (LIBOR) [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Long-term debt Number of intercompany promissory notes Number of Intercompany Promissory Notes Number of Intercompany Promissory Notes Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Basis spread on variable rate, percent Debt Instrument, Basis Spread on Variable Rate Maximum consolidated leverage ration during one year following acquisitions Maximum Consolidated Leverage Ratio During One Year Following Acquisitions Represents the consolidated leverage ratio required per the debt agreement during any one-year period following certain acquisitions. Leverage capital ration required during other periods Leverage Capital Ratio Required During Other Periods Represents the consolidated leverage ratio required per the debt agreement during periods other than than one-year period following certain types of acquisitions Additional ownership interest 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 Inventory, Current [Table] Inventory, Current [Table] Inventory [Line Items] Inventory [Line Items] Finished products Inventory, Finished Goods, Gross Feedstock, additives and chemicals Inventory, Work in Process and Raw Materials Inventories Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Site Lease Agreement [Member] Site Lease Agreement [Member] Site Lease Agreement [Member] Westlake [Member] Senior unsecured revolving credit facility [Member] Outstanding letters of credit Letters of Credit Outstanding, Amount Outstanding debt Long-term Debt Unamortized discount on senior notes Debt Instrument, Unamortized Discount Number of site lease agreements Lessee Leasing Arrangements, Operating Leases, Number Lessee Leasing Arrangement, Operating Leases, Number Lease term Lessee Leasing Arrangements, Operating Leases, Term of Contract Operating lease rent expense Operating Leases, Rent Expense Loss Contingencies [Table] Loss Contingencies [Table] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Goodrich and PolyOne [Member] Goodrich and PolyOne [Member] Goodrich and PolyOne [Member] Litigation Status [Axis] Litigation Status [Axis] Litigation Status [Domain] Litigation Status [Domain] Settled Litigation [Member] Settled Litigation [Member] Pending Litigation [Member] Pending Litigation [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Unfavorable Regulatory Action [Member] Unfavorable Regulatory Action [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Percentage of costs related to environmental issues to be paid by PolyOne Site Contingency, Third Party Recovery, Percentage Represents environmental costs percentage net of recoveries from third parties, to be paid by a counterparty Minimum number of years between arbitrations Loss Contingency, Arbitration Interval Period Represents the minimum number of years that must pass before another arbitration proceeding may be held to adjust the environmental costs percentage paid by a counterparty. Costs incurred for environmental remediation services Environmental Remediation Expense Reimbursement of remediation costs sought by PolyOne Loss Contingency, Damages Sought, Value Possible amount of claims in settlement for compliance violations Loss Contingency, Estimate of Possible Loss Summary Of Carrying And Fair Values Of Long-Term Debt Fair Value, by Balance Sheet Grouping [Table Text Block] Financial Instruments Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Accounts Receivable - Third Parties Loans, Notes, Trade and Other Receivables Disclosure [Text Block]