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Derivatives Not Designated as
Hedging Instruments

Location of Gain (Loss)
Recognized in Income on Derivative

Year Ended December 31, 2014

Commodity forward contracts

Cost of sales

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Document And Entity Information - USD ($) $ in Millions	12 Months Ended
Document And Entity Information - USD ($) $ in Millions	Dec. 31, 2016	Mar. 02, 2017	Jun. 30, 2016
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Entity Registrant Name	WESTLAKE CHEMICAL PARTNERS LP
Entity Central Index Key	0001604665
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 253.6
Common units [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		14,373,615
Subordinated units [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		12,686,115

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 88,900	$ 169,559
Accounts receivable, net—Westlake Chemical Corporation (Westlake)	126,977	39,655
Accounts receivable, net—third parties	12,085	11,927
Inventories	3,934	3,879
Prepaid expenses and other current assets	269	267
Total current assets	232,165	225,287
Property, plant and equipment, net	1,222,238	1,020,469
Goodwill	5,814	5,814
Other assets, net
Deferred charges and other assets, net	95,011	38,779
Total other assets, net	100,825	44,593
Total assets	1,555,228	1,290,349
Current liabilities
Accounts payable—Westlake	12,130	15,550
Accounts payable—third parties	9,930	18,737
Accrued liabilities	15,717	23,407
Total current liabilities	37,777	57,694
Long-term debt payable to Westlake	594,629	384,006
Deferred income taxes	1,736	1,392
Other liabilities	123	90
Total liabilities	634,265	443,182
Commitments and contingencies (Notes 8 and 18)
EQUITY
Accumulated other comprehensive income	200	280
Total Westlake Chemical Partners LP partners' capital	102,484	96,561
Noncontrolling interest in Westlake Chemical OpCo LP (OpCo)	818,479	750,606
Total equity	920,963	847,167
Total liabilities and equity	1,555,228	1,290,349
Limited Partner [Member] \| Common units [Member] \| Public [Member]
EQUITY
Limited partners' capital	297,367	294,565
Total equity	297,367	294,565
Limited Partner [Member] \| Common units [Member] \| Westlake [Member]
EQUITY
Limited partners' capital	4,813	4,502
Total equity	4,813	4,502
Limited Partner [Member] \| Subordinated units [Member] \| Westlake [Member]
EQUITY
Limited partners' capital	42,534	39,786
Total equity	42,534	39,786
General Partner [Member] \| Westlake [Member]
EQUITY
General partner—Westlake	(242,430)	(242,572)
Total equity	$ (242,430)	$ (242,572)

Consolidated Balance Sheets (Parenthetical) - shares	Dec. 31, 2016	Dec. 31, 2015
Common units [Member] \| Westlake [Member]
Units issued	1,436,115	1,436,115
Units outstanding	1,436,115	143,611
Common units [Member] \| Public [Member]
Units issued	12,937,500	12,937,500
Units outstanding	12,937,500	12,937,500
Subordinated units [Member] \| Westlake [Member]
Units issued	12,686,115	12,686,115
Units outstanding	12,686,115	12,686,115

Consolidated and Combined Statements of Operations - USD ($) $ in Thousands	5 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net sales - Westlake		$ 853,719	$ 834,918
Net co-products, ethylene and feedstock sales—third parties		133,017	172,303
Net sales		986,736	1,007,221
Cost of sales		595,405	624,339
Gross profit		391,331	382,882
Selling, general and administrative expenses		24,887	23,550
Income from operations		366,444	359,332
Other income (expense)
Interest expense—Westlake		(12,607)	(4,967)
Other income, net		601	160
Income before income taxes		354,438	354,525
Provision for income taxes	$ 1,065	1,035	672
Net income	148,486	353,403	353,853
Less: Net income attributable to noncontrolling interest in OpCo	134,909	312,463	314,022
Limited partners' interest in net income subsequent to IPO	$ 13,577	$ 40,940	$ 39,831	$ 13,577
Weighted average limited partner units outstanding (basic and diluted)
Weighted average limited units outstanding (basic and diluted)		27,059,730	27,059,730	27,059,730
Distributions per common unit (usd per unit)	$ 0.45	$ 1.29	$ 1.15
Common units [Member]
Other income (expense)
Limited partners' interest in net income subsequent to IPO		$ 21,597	$ 21,158	$ 7,213
Net income attributable to Westlake Chemical Partners LP subsequent to initial public offering per limited partner unit (basic and diluted)
Income per limited partner unit (usd per unit)	0.50	$ 1.50	$ 1.47	$ 0.50
Weighted average limited partner units outstanding (basic and diluted)
Weighted average limited units outstanding (basic and diluted)		14,373,615	14,373,615	14,373,615
Subordinated units [Member]
Other income (expense)
Limited partners' interest in net income subsequent to IPO		$ 19,062	$ 18,673	$ 6,364
Net income attributable to Westlake Chemical Partners LP subsequent to initial public offering per limited partner unit (basic and diluted)
Income per limited partner unit (usd per unit)	$ 0.50	$ 1.50	$ 1.47	$ 0.50
Weighted average limited partner units outstanding (basic and diluted)
Weighted average limited units outstanding (basic and diluted)		12,686,115	12,686,115	12,686,115
Public [Member] \| Common units [Member]
Weighted average limited partner units outstanding (basic and diluted)
Weighted average limited units outstanding (basic and diluted)	12,937,500	12,937,500	12,937,500
Westlake [Member] \| Common units [Member]
Weighted average limited partner units outstanding (basic and diluted)
Weighted average limited units outstanding (basic and diluted)	1,436,115	1,436,115	1,436,115
Westlake [Member] \| Subordinated units [Member]
Weighted average limited partner units outstanding (basic and diluted)
Weighted average limited units outstanding (basic and diluted)	12,686,115	12,686,115	12,686,115
Predecessor [Member]
Net sales - Westlake				$ 1,292,089
Net co-products, ethylene and feedstock sales—third parties				457,611
Net sales				1,749,700
Cost of sales				1,003,888
Gross profit				745,812
Selling, general and administrative expenses				29,256
Income from operations				716,556
Other income (expense)
Interest expense—Westlake				(10,499)
Other income, net				3,151
Income before income taxes				709,208
Provision for income taxes				199,388
Net income		$ 0	$ 0	$ 509,820

Consolidated Statement of Comprehensive Income - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 353,403,000	$ 353,853,000
Adjustments in fair value of cash flow hedge	(416,000)	85,000
Reclassification of losses to net income	336,000	195,000
Total other comprehensive income	(80,000)	280,000
Comprehensive income	353,323,000	354,133,000
Comprehensive income attributable to noncontrolling interest in OpCo	312,463,000	314,022,000
Comprehensive income attributable to Westlake Chemical Partners LP	$ 40,860,000	$ 40,111,000

Consolidated and Combined Statements of Changes in Equity - USD ($) $ in Thousands	Total	Noncontrolling Interest in OpCo [Member]	AOCI Attributable to Parent [Member]	Westlake [Member] General Partner [Member]	Common units [Member] Public [Member] Limited Partner [Member]	Common units [Member] Westlake [Member] Limited Partner [Member]	Subordinated units [Member] Westlake [Member] Limited Partner [Member]
Equity, beginning balance (Predecessor [Member]) at Dec. 31, 2013	$ 455,432
Equity, beginning balance at Dec. 31, 2013	455,432
Stockholders' Equity [Roll Forward]
Net income \| Predecessor [Member]	361,334
Net income	361,334
Net distributions to Westlake \| Predecessor [Member]	(448,101)
Net distributions to Westlake	(448,101)
Predecessor net liabilities not assumed by OpCo \| Predecessor [Member]	239,706
Predecessor net liabilities not assumed by OpCo	239,706
Equity, ending balance (Predecessor [Member]) at Aug. 03, 2014	608,371
Equity, ending balance at Aug. 03, 2014	608,371
Equity, beginning balance (Predecessor [Member]) at Dec. 31, 2013	455,432
Equity, beginning balance at Dec. 31, 2013	455,432
Stockholders' Equity [Roll Forward]
Net income \| Predecessor [Member]	509,820
Equity, ending balance at Dec. 31, 2014	834,950	$ 747,426		$ (242,572)	$ 290,377	$ 4,038	$ 35,681
Equity, beginning balance (Predecessor [Member]) at Aug. 03, 2014	608,371
Equity, beginning balance at Aug. 03, 2014	608,371
Stockholders' Equity [Roll Forward]
Net income	148,486	134,909			6,493	720	6,364
Allocation of net investment to unitholders \| Predecessor [Member]	(608,371)
Allocation of net investment to unitholders		573,329				3,563	31,479
Proceeds from initial public offering, net of finance and other offering costs	286,088				286,088
Distribution to the noncontrolling interest in OpCo	(151,729)	(151,729)
Purchase of additional interest in OpCo	0	242,572		(242,572)
Quarterly distribution to unitholders	(4,611)				(2,204)	(245)	(2,162)
Quarterly distribution to noncontrolling interest retained in OpCo by Westlake	(51,655)	(51,655)
Equity, ending balance at Dec. 31, 2014	834,950	747,426		(242,572)	290,377	4,038	35,681
Stockholders' Equity [Roll Forward]
Net income \| Predecessor [Member]	0
Net income	353,853	314,022			19,044	2,114	18,673
Net effect of cash flow hedge	280		$ 280
Quarterly distribution to unitholders	(31,074)				(14,856)	(1,650)	(14,568)
Quarterly distribution to noncontrolling interest retained in OpCo by Westlake	(310,842)	(310,842)
Equity, ending balance at Dec. 31, 2015	847,167	750,606	280	(242,572)	294,565	4,502	39,786
Stockholders' Equity [Roll Forward]
Net income \| Predecessor [Member]	0
Net income	353,403	312,463		281	19,440	2,157	19,062
Net effect of cash flow hedge	(80)		(80)
Quarterly distribution to unitholders	(34,937)			(139)	(16,638)	(1,846)	(16,314)
Quarterly distribution to noncontrolling interest retained in OpCo by Westlake	(244,590)	(244,590)
Equity, ending balance at Dec. 31, 2016	$ 920,963	$ 818,479	$ 200	$ (242,430)	$ 297,367	$ 4,813	$ 42,534

Consolidated and Combined Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities
Net income	$ 353,403	$ 353,853
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	98,210	81,210
Charged to Expense	394	170	$ 65
Loss from disposition of property, plant and equipment	3,021	1,812
Deferred income taxes	344	(456)
Income from equity method investment, net of dividends	0	0
Changes in operating assets and liabilities
Accounts receivable - third parties	(552)	25,424
Net accounts receivable - Westlake	(90,742)	(11,836)
Inventories	(55)	2,755
Prepaid expenses and other current assets	(2)	(55)
Accounts payable	(2,175)	836
Accrued and other liabilities	3,791	2,317
Other, net	(77,911)	(3,488)
Net cash provided by operating activities	287,726	452,542
Cash flows from investing activities
Additions to property, plant and equipment	(299,638)	(231,185)
Proceeds from disposition of assets	157	0	0
Settlements of derivative instruments	0	0
Net cash used for investing activities	(299,481)	(231,185)
Cash flows from financing activities
Proceeds from debt payable to Westlake	212,175	291,709
Repayment of debt payable to Westlake	(1,552)	(135,341)	0
Quarterly distributions to noncontrolling interest retained in OpCo by Westlake	(244,590)	(310,842)
Quarterly distributions to unitholders	(34,937)	(31,074)
Repayment of related party debt with proceeds from the initial public offering	0	0
Net proceeds from issuance of common units	0	0
Proceeds from initial public offering distributed to Westlake	0	0
Net distributions to Westlake prior to initial public offering	0	0
Net cash used for financing activities	(68,904)	(185,548)
Net (decrease) increase in cash and cash equivalents	(80,659)	35,809
Cash and cash equivalents at beginning of period	169,559	133,750
Cash and cash equivalents at end of period	88,900	169,559	133,750
Predecessor [Member]
Cash flows from operating activities
Net income	$ 0	0	509,820
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			77,611
Charged to Expense			65
Loss from disposition of property, plant and equipment			1,544
Deferred income taxes			8,608
Income from equity method investment, net of dividends			1,073
Changes in operating assets and liabilities
Accounts receivable - third parties			(31,551)
Net accounts receivable - Westlake			(11,059)
Inventories			24,686
Prepaid expenses and other current assets			(624)
Accounts payable			(4,915)
Accrued and other liabilities			20,166
Other, net			8,588
Net cash provided by operating activities			604,012
Cash flows from investing activities
Additions to property, plant and equipment			(202,823)
Settlements of derivative instruments			(133)
Net cash used for investing activities			(202,956)
Cash flows from financing activities
Proceeds from debt payable to Westlake			181,642
Quarterly distributions to noncontrolling interest retained in OpCo by Westlake			(51,655)
Quarterly distributions to unitholders			(4,611)
Repayment of related party debt with proceeds from the initial public offering			(78,940)
Net proceeds from issuance of common units			286,088
Proceeds from initial public offering distributed to Westlake			(151,729)
Net distributions to Westlake prior to initial public offering			(448,101)
Net cash used for financing activities			(267,306)
Net (decrease) increase in cash and cash equivalents			133,750
Cash and cash equivalents at beginning of period		$ 133,750	0
Cash and cash equivalents at end of period			$ 133,750

Description Of Business And Significant Accounting Policies

12 Months Ended

Dec. 31, 2016

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Description Of Business And Significant Accounting Policies

Description of Business and Significant Accounting Policies

Description of Business

Westlake Chemical Partners LP ("Westlake Chemical Partners LP" or the "Partnership") is a Delaware limited partnership formed in March 2014 to operate, acquire and develop ethylene production facilities and related assets. On August 4, 2014, the Partnership completed an initial public offering (the "IPO") of 12,937,500 common units representing limited partner interests. In connection with the IPO, the Partnership acquired a 10.6% interest in Westlake Chemical OpCo LP ("OpCo") and a 100% interest in Westlake Chemical OpCo GP LLC ("OpCo GP"), which is the general partner of OpCo. On April 29, 2015, the Partnership purchased an additional 2.7% newly-issued limited partner interest in OpCo for approximately $135,341, resulting in an aggregate 13.3% limited partner interest in OpCo effective April 1, 2015. OpCo owns three ethylene production facilities and a common carrier ethylene pipeline (collectively, the "Contributed Assets").

References in these financial statements to the Partnership, OpCo and OpCo GP used in the present tense or prospectively refer to the period subsequent to the IPO. References in these financial statements to the "Predecessor" refer to Westlake Chemical Partners LP Predecessor, the Partnership's predecessor for accounting purposes and refer to the time periods prior to the IPO. References to "Westlake" refer collectively to Westlake Chemical Corporation and its subsidiaries, other than the Partnership, OpCo and OpCo GP.

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

The Partnership sells ethylene production in excess of volumes sold to Westlake, as well as all of the co-products resulting from the ethylene production, including propylene, crude butadiene, pyrolysis gasoline and hydrogen, directly to third parties on either a spot or contract basis. Co-products sold to third parties continue to be transported by rail or truck. Net proceeds (after transportation and other costs) from the sales of ethylene co-products that result from the production of ethylene purchased by Westlake are netted against the ethylene price charged to Westlake under the Ethylene Sales Agreement, thereby reducing the Partnership's exposure to fluctuations in the market prices of these co-products.

The Partnership's operations consist of activities relating solely to the Contributed Assets. The Predecessor's operations consisted of the entire ethylene business of Westlake, including the activities of the Contributed Assets, as well as activities which were retained by Westlake. Ethylene business activities retained by Westlake include, but are not limited to, procuring feedstock, managing inventory and commodity risk and transporting ethylene from manufacturing facilities.

Basis of Presentation

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

The Partnership holds a 13.3% limited partner interest and the entire non-economic general partner interest in OpCo. The remaining 86.7% limited partner interest in OpCo is owned directly by Westlake, which has no rights to direct the activities that most significantly impact the economic performance of OpCo. As a result of the fact that substantially all of OpCo's activities are conducted on behalf of Westlake, and the fact that OpCo exhibits disproportionality of voting rights to economic interest, OpCo was deemed to be a variable interest entity. The Partnership, through its ownership of OpCo's general partner, has the power to direct the activities that most significantly impact the economic performance of OpCo, and it also has the obligation or right to absorb losses or receive benefits from OpCo that could potentially be significant to OpCo. As such, the Partnership was determined to be OpCo's primary beneficiary and therefore consolidates OpCo's results of operations and financial position. Westlake's retained interest of 86.7% is recorded as noncontrolling interest in the Partnership's consolidated financial statements.

All financial information presented for the periods after the IPO represents the consolidated results of operations, financial position and cash flows of the Partnership. Financial information for the period prior to the IPO represents the combined results of operations, financial position and cash flows of the Predecessor. The consolidated and combined financial statements for the year ended December 31, 2014 were prepared as follows:


•	The consolidated statement of operations for the year ended December 31, 2014 consists of the consolidated results of the Partnership for the period from August 4, 2014 through December 31, 2014 and the combined results of the Predecessor for the period from January 1, 2014 through August 3, 2014.


•	The consolidated statement of cash flows for the year ended December 31, 2014 consists of the consolidated results of the Partnership for the period from August 4, 2014 through December 31, 2014 and the combined results of the Predecessor for the period from January 1, 2014 through August 3, 2014.

•

The consolidated statement of changes in equity for the year ended December 31, 2014 consists of the combined activity for the Predecessor prior to August 4, 2014, and the consolidated activity for the Partnership at and subsequent to the IPO on August 4, 2014 through December 31, 2014. The combined statement of changes in equity for the year ended December 31, 2013 consists entirely of the combined activity of the Predecessor.

Cash and Cash Equivalents

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

Allowance for Doubtful Accounts

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

Inventories

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

Property, Plant and Equipment

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

Interest expense is capitalized for qualifying assets under construction. Capitalized interest costs are included in property, plant and equipment and are depreciated over the useful life of the related asset. Capitalized interest was $5,961, $5,116 and $2,638 for the years ended December 31, 2016, 2015 and 2014. Repair and maintenance costs are charged to operations as incurred. Gains and losses on the disposal or retirement of property, plant and equipment are reflected in the statement of operations when the assets are sold or retired.

The accounting guidance for asset retirement obligations requires the recording of liabilities equal to the fair value of asset retirement obligations and corresponding additional asset costs, when there is a legal asset retirement obligation as a result of existing or enacted law, statute or contract. The Partnership has conditional asset retirement obligations for the removal and disposal of hazardous materials from certain of the Partnership's manufacturing facilities. However, no asset retirement obligations have been recognized because the fair value of the conditional legal obligation cannot be measured due to the indeterminate settlement date of the obligation. Settlement of these conditional asset retirement obligations is not expected to have a material adverse effect on the Partnership's financial condition, results of operations or cash flows in any individual reporting period.

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



Classification		Years

Buildings and improvements		25
Plant and equipment		25
Ethylene pipeline		35
Other		3-10

Impairment of Long-Lived Assets

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

Impairment of Goodwill and Intangible Assets

The accounting guidance for goodwill and intangible assets requires that goodwill and indefinite-lived intangible assets are tested for impairment at least annually. Other intangible assets with finite lives are amortized over their estimated useful life and reviewed for impairment in accordance with the provisions of the accounting guidance. As of December 31, 2016, the Partnership's recorded goodwill was $5,814. See Note 7 for more information on the Partnership's annual goodwill impairment test.

Turnaround Costs

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

Exchanges

The Partnership enters into inventory exchange transactions with respect to ethylene. These exchanges are settled in like-kind quantities and are valued at lower of cost or market. Cost is determined using the FIFO method.

Concentration of Credit Risk

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

Revenue Recognition

Revenue is recognized when persuasive evidence of an arrangement exists, products are delivered to the customer, the sales price is fixed or determinable, and collectibility is reasonably assured. Title and risk of loss passes to the customer upon delivery under executed customer purchase orders or contracts. Provisions for discounts, rebates and returns are provided for in the same period as the related sales are recorded.

Net Income per Unit

The accounting guidance for earnings per unit requires the Partnership to present basic earnings per unit and diluted earnings per unit. Net income per unit applicable to common limited partner units and to subordinated limited partner units is computed by dividing the respective limited partners' interest in net income by the weighted average number of common units, subordinated units and incentive distribution rights outstanding. Because the Partnership has more than one class of participating securities, it uses the two-class method when calculating the net income per unit applicable to limited partners. The classes of participating securities include common units and subordinated units. Diluted net income per limited partner unit is the same as basic net income per limited partner unit, as there were no potentially dilutive common or subordinated units outstanding as of December 31, 2016 and 2015.

Derivative Instruments

The accounting guidance for derivative instruments and hedging activities requires that the Partnership and the Predecessor recognize all derivative instruments on the balance sheet at fair value, and changes in the derivative's fair value must be currently recognized in earnings or comprehensive income, depending on the designation of the derivative. If the derivative is designated as a fair value hedge, the changes in the fair value of the derivative and of the hedged item attributable to the hedged risk are recognized in earnings. If the derivative is designated as a cash flow hedge, the effective portion of the change in the fair value of the derivative is recorded in comprehensive income and is recognized in the statement of operations when the hedged item affects earnings. Ineffective portions of changes in the fair value of cash flow hedges are recognized in earnings currently.

The Predecessor utilized commodity derivative instruments to reduce price risks by purchasing or selling futures on established exchanges. The Partnership did not enter into any commodity derivative instruments since the date of the IPO on August 4, 2014. During 2015, the Partnership entered into an interest rate contract with Westlake designed to reduce the risks of variability of the interest rates under the MLP Revolver. The interest rate contract fixed the LIBOR component of the interest rate for a portion of the MLP Revolver balance and was designated as a cash flow hedge. During 2014, the Predecessor had no cash flow hedges. See Note 14 for more information on the derivative instruments and Note 15 for a summary of the fair value of derivative instruments.

Environmental Costs

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

Fair Value of Financial Instruments

The amounts reported in the consolidated balance sheets for cash and cash equivalents, accounts receivable, net and accounts payable approximate their fair value due to the short maturities of these instruments. The fair value of the Partnership's debt differs from the carrying value due to the long-term maturities of the debt. The fair value of the financial instruments is estimated using quoted market prices in active markets and observable market-based inputs or unobservable inputs that are corroborated by market data when active markets are not available or unobservable inputs that are not corroborated by market data. See Note 15 for more information on the fair value of financial instruments.

Income Taxes

The Partnership is a limited partnership and is treated as a partnership for U.S. federal income tax purposes and, therefore, is not liable for entity-level federal income taxes. The Partnership is, however, subject to state and local income taxes. The Predecessor's operating results were included in Westlake's consolidated U.S. federal and state income tax returns. Amounts presented in the combined financial statements prior to the IPO relate to income taxes that have been determined on a separate tax return basis and the Predecessor's contribution to Westlake Chemical Corporation's net operating losses and tax credits have been included in the Predecessor's financial statements. The Predecessor utilized the liability method of accounting for deferred income taxes. Under the liability method, deferred tax assets or liabilities are recorded based upon temporary differences between the tax basis of assets and liabilities and their carrying values for financial reporting purposes. Deferred tax expense or benefit is the result of changes in the deferred tax assets and liabilities during the period. Valuation allowances were recorded against deferred tax assets when it was considered more likely than not that the deferred tax assets will not be realized on a separate tax return basis.

Segment Reporting

The Partnership accounts for segment reporting in accordance with the Financial Accounting Standards Board guidance, which establishes standards for entities to report information about the operating segments and geographic areas in which they operate. The Partnership only operates one segment (ethylene production) and all of its operations are located in the United States.

Use of Estimates

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

Net Investment

In the consolidated and combined statements of changes in equity, net investment represents Westlake's historical investment in the Predecessor, its accumulated net earnings after taxes and the net effect of transactions with, and allocations from, Westlake.

Other Assets

Certain other assets (see Note 7) are amortized over periods ranging from five to 15 years using the straight-line method.

Other Comprehensive Income

The Partnership has reported no comprehensive income for the year ended December 31, 2014 due to the absence of items of other comprehensive income.

Initial Public Offering and Purchase of Additional Interests

12 Months Ended

Dec. 31, 2016

Equity [Abstract]

Initial Public Offering and Purchase of Additional Interests

Initial Public Offering

On July 30, 2014, the Partnership's common units began trading on the New York Stock Exchange under the ticker symbol "WLKP." On August 4, 2014, the Partnership completed the IPO of 12,937,500 common units at a price to the public of $24.00 per unit ($22.53 per unit net of underwriting discount), including 1,687,500 common units that were issued pursuant to the exercise in full of the underwriters' over-allotment option.

In connection with the IPO, in exchange for Westlake's contribution of a 5.8% limited partner interest in OpCo and OpCo's general partner interest to the Partnership, Westlake received:


•	1,436,115 common units and 12,686,115 subordinated units; and


•	the Partnership's general partner interest and its incentive distribution rights.

The Partnership received net proceeds of $286,088 from the IPO, net of underwriting discounts, structuring fees and offering expenses of approximately $24,412. The Partnership used the net proceeds from the IPO to purchase an additional 4.8% limited partner interest in OpCo, resulting in the Partnership owning a 10.6% limited partner interest in OpCo. The Partnership recorded the incremental 4.8% limited partner interest in OpCo at its historical carrying value of $43,516 and the excess cash paid over historical carrying value of $242,572 as a decrease to the General partner—Westlake capital account.

OpCo used the $286,088 it received from the Partnership in exchange for a 4.8% limited partner interest in OpCo to (1) establish a $55,419 turnaround reserve, (2) reimburse Westlake $151,729 for the Pre-August 2013 Capex, and (3) repay $78,940 of the August 2013 Promissory Notes assumed by OpCo. Immediately after the repayment, the outstanding indebtedness payable to Westlake under the August 2013 Promissory Notes was $167,116.

Agreements with Westlake and Related Parties

The agreements described below became effective on August 4, 2014, concurrent with the closing of the IPO.

Ethylene Sales Agreement

OpCo entered into a 12-year ethylene sales agreement with Westlake (the "Ethylene Sales Agreement"). The Ethylene Sales Agreement requires Westlake to purchase a minimum volume of ethylene each year equal to 95% of OpCo's planned ethylene production per year (the "Minimum Commitment"), subject to certain exceptions and a maximum commitment of 3.8 billion pounds per year. So long as Westlake is not in default under the Ethylene Sales Agreement, if OpCo's actual production exceeds planned production, Westlake has the option to purchase up to 95% of the excess production (the "Excess Production Option").

The fee for each pound of ethylene purchased by Westlake from OpCo up to the Minimum Commitment in any calendar year will equal:


•	the actual price OpCo pays Westlake to purchase ethane (or other feedstock, such as propane, if applicable) to produce each pound of ethylene, subject to a specified cap and a floor on the amount of feedstock that should be needed to produce each pound of ethylene; plus


•	the actual price OpCo pays Westlake to purchase natural gas to produce each pound of ethylene, subject to a specified cap and a floor on the amount of natural gas that should be needed to produce each pound of ethylene; plus


•	OpCo's estimated operating costs (including selling, general and administrative expenses), divided by OpCo's planned ethylene production for the year (in pounds); plus


•	a five-year average of OpCo's expected future maintenance capital expenditures and other turnaround expenditures, divided by OpCo's planned ethylene production capacity for the year (in pounds); less


•	the proceeds (on a per pound of ethylene basis) received by OpCo from the sale of co-products (including, but not limited to, propylene, crude butadiene, pyrolysis gasoline and hydrogen) associated with producing the ethylene purchased by Westlake; plus


•	a $0.10 per pound margin.

The fee for the Excess Production Option, if exercised, equals OpCo's estimated variable operating costs of producing the incremental ethylene, net of revenues from co-products sales plus a $0.10 per pound margin.

The estimated operating costs and the expected future maintenance capital expenditures and other turnaround expenditures will be adjusted at the end of each year, to be applicable for the fee for the next calendar year, to reflect certain changes in forecasted costs.

The result of the fee structure is that OpCo should recover the portion of its total operating costs and maintenance capital expenditures and other turnaround expenditures corresponding to the portion of OpCo's aggregate production that is purchased by Westlake. Any shortfall in recovery of such costs is recognized during the current year and is recoverable from Westlake in the subsequent year.

The Ethylene Sales Agreement has an initial term extending until December 31, 2026 and automatically renews thereafter for successive 12-month terms unless terminated.

Feedstock Supply Agreement

OpCo entered into a feedstock supply agreement with Westlake, pursuant to which Westlake agreed to sell to OpCo ethane and other feedstock in amounts sufficient for OpCo to produce the ethylene to be sold under the Ethylene Sales Agreement (the "Feedstock Supply Agreement"). The Feedstock Supply Agreement provides that OpCo may obtain feedstock from Westlake based on Westlake's total cost of purchasing and delivering the feedstock, including applicable transportation, storage and other costs. Title and risk of loss for all feedstock purchased by OpCo through the Feedstock Supply Agreement passes to OpCo upon delivery to one of three delivery points described in the Feedstock Supply Agreement.

The Feedstock Supply Agreement has an initial term extending until December 31, 2026 and automatically renews thereafter for successive 12-month terms unless terminated by either party; provided, however, that such agreement can only be renewed in the event the Ethylene Sales Agreement is renewed simultaneously. The Feedstock Supply Agreement may, in certain circumstances, terminate concurrently with the termination of the Ethylene Sales Agreement.

Services and Secondment Agreement

OpCo entered into a Services and Secondment Agreement with Westlake, pursuant to which OpCo provides Westlake with certain services required for the operation of Westlake's facilities; and Westlake provides OpCo with comprehensive operating services for OpCo's facilities, ranging from services relating to the maintenance and operations of the common facilities necessary for the operation of OpCo's units, to making available certain shared utilities such as electricity and natural gas that are necessary for the operation of OpCo's units. Westlake also seconds employees to OpCo to allow OpCo to operate its facilities. Such seconded employees will be under the control of OpCo while they work on OpCo's facilities.

The Services and Secondment Agreement has an initial 12-year term. The Services and Secondment Agreement may be renewed thereafter upon agreement of the parties and shall automatically terminate if the Ethylene Sales Agreement terminates under certain circumstances. Westlake and OpCo each can terminate the Services and Secondment Agreement under certain circumstances, including if the other party materially defaults on the performance of its obligations and such default continues for a 30-day period.

Site Lease Agreements

OpCo entered into two site lease agreements with Westlake pursuant to which Westlake leases to OpCo the real property underlying Lake Charles Olefins and Calvert City Olefins, respectively, and grants OpCo rights to access and use certain other portions of Westlake's ethylene production facilities that are necessary to operate OpCo's production facilities. OpCo owes Westlake one dollar per site per year. The site lease agreements each have a term of 50 years. Each of the site lease agreements may be renewed if agreed by the parties.

Omnibus Agreement

The Partnership entered into an Omnibus Agreement with Westlake that addresses (1) Westlake's indemnification of the Partnership for certain matters, including environmental and tax matters, (2) the provision by Westlake of certain management and other general and administrative services to the Partnership and its general partner and (3) the Partnership's reimbursement to Westlake for such services. The Omnibus Agreement also addresses Westlake's right of first refusal on any proposed transfer of the ethylene production facilities that serve Westlake's other facilities and Westlake's right of first refusal on any proposed transfer of the Partnership's equity interests in OpCo.

Exchange Agreement

OpCo and Westlake entered into an exchange agreement, which had an initial term through August 1, 2015 and is continuing year to year thereafter, unless and until terminated by either party. Under the exchange agreement, OpCo may require Westlake to deliver up to 200 million pounds of ethylene for OpCo per year from the Site Leases to an ethylene hub in Mt. Belvieu, Texas, for which OpCo would be required to pay an exchange fee of $0.006 per pound.

Purchase of Additional Interests in OpCo

On April 29, 2015, the Partnership purchased an additional 2.7% newly-issued limited partner interest in OpCo for approximately $135,341, resulting in an aggregate 13.3% limited partner interest in OpCo effective April 1, 2015. In order to fund this purchase, the Partnership entered into a revolving credit facility with a total borrowing capacity of $300,000 with a subsidiary of Westlake. Westlake owns the remaining 86.7% limited partner interest in OpCo, which is recorded as noncontrolling interest in the 2015 consolidated financial statements.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

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Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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+ Details

Recent Accounting Pronouncements	12 Months Ended
Recent Accounting Pronouncements	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Revenue from Contracts with Customers (ASU No. 2014-09) In May 2014, the Financial Accounting Standards Board ("FASB") issued an accounting standards update on a comprehensive new revenue recognition standard that will supersede the existing revenue recognition guidance. The new accounting guidance creates a framework by which an entity will allocate the transaction price to separate performance obligations and recognize revenue when each performance obligation is satisfied. Under the new standard, entities will be required to use judgment and make estimates, including identifying performance obligations in a contract, estimating the amount of variable consideration to include in the transaction price, allocating the transaction price to each separate performance obligation and determining when an entity satisfies its performance obligations. The standard allows for either "full retrospective" adoption, meaning that the standard is applied to all of the periods presented with a cumulative catch-up as of the earliest period presented, or "modified retrospective" adoption, meaning the standard is applied only to the most current period presented in the financial statements with a cumulative catch-up as of the current period. In July 2015, the FASB deferred the effective date for the revenue recognition standard. The accounting standard will now be effective for reporting periods beginning after December 15, 2017. The Partnership is in the process of evaluating the impact that the new accounting guidance will have on its consolidated financial position, results of operations and cash flows. Leases (ASU No. 2016-02) In February 2016, the FASB issued an accounting standards update on a new lease standard that will supersede the existing lease guidance. The standard requires a lessee to recognize assets and liabilities related to long-term leases that are classified as operating leases under current guidance on its balance sheet. An asset would be recognized related to the right to use the underlying asset and a liability would be recognized related to the obligation to make lease payments over the term of the lease. The standard also requires expanded disclosures related to leases. The accounting standard will be effective for reporting periods beginning after December 15, 2018. The Partnership is in the process of evaluating the impact that the new accounting guidance will have on its consolidated financial position, results of operations and cash flows. Credit Losses (ASU No. 2016-13) In June 2016, the FASB issued an accounting standards update providing new guidance for the accounting for credit losses on loans and other financial instruments. The new guidance introduces an approach based on expected losses to estimate credit losses on certain types of financial instruments. The standard also modifies the impairment model for available-for-sale debt securities and provides for a simplified accounting model for purchased financial assets with credit deterioration since their origination. The accounting standard will be effective for reporting periods beginning after December 15, 2019. The Partnership is in the process of evaluating the impact that the new accounting guidance will have on its consolidated financial position, results of operations and cash flows. Cash Flows (ASU No. 2016-15) In August 2016, the FASB issued an accounting standards update providing new guidance on the classification of certain cash receipts and payments including debt extinguishment costs, debt prepayment costs, settlement of zero-coupon debt instruments, contingent consideration payments, proceeds from the settlement of insurance claims and life insurance policies and distributions received from equity method investees in the statement of cash flows. This update is required to be applied using the retrospective transition method to each period presented unless it is impracticable to be applied retrospectively. In such situation, this guidance is to be applied prospectively. The accounting standard will be effective for reporting periods beginning after December 15, 2017. The Partnership is in the process of evaluating the impact that the new accounting guidance will have on its consolidated financial position, results of operations and cash flows. Business Combinations (ASU No. 2017-01) In January 2017, the FASB issued an accounting standard update to assist entities with evaluating when a set of transferred assets and activities is a business. The guidance requires an entity to evaluate if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets; if so, the set of transferred assets and activities is not a business. The guidance also requires a business to include at least one substantive process and narrows the definition of outputs by more closely aligning it with how outputs are described in ASC 606. The accounting standard will be effective for reporting periods beginning after December 15, 2017. The Partnership is in the process of evaluating the impact that the new accounting guidance will have on its consolidated financial position, results of operations and cash flows. Recently Adopted Accounting Standards Going Concern (ASU No. 2014-15) In August 2014, the FASB issued an accounting standard update providing guidance related to evaluating whether there is substantial doubt about the reporting entity's ability to continue as a going concern and about related financial statement note disclosures. Disclosures are required if there is substantial doubt as to the Partnership's continuation as a going concern within one year after the issue date of financial statements. The standard provides guidance for making the assessment, including consideration of management's plans which may alleviate doubt regarding the Partnership's ability to continue as a going concern. The accounting standard became effective for the annual reporting period ending after December 15, 2016, and all annual and interim periods thereafter. The Partnership adopted this accounting standard effective December 31, 2016 and the adoption did not have an impact on the Partnership's consolidated financial position, results of operations and cash flows. Amendments to the Consolidation Analysis (ASU No. 2015-02) In February 2015, the FASB issued an accounting standards update making certain changes to the current consolidation guidance. The amendments affect both the variable interest entity and voting interest entity consolidation models. The new standard changes the consideration of substantive rights, related party interests and fees paid to the decision maker when applying the variable interest entity consolidation model and eliminates certain guidance for limited partnerships and similar entities under the voting interest consolidation model. The accounting standard is effective for annual periods beginning after December 15, 2015. The Partnership adopted this accounting standard effective January 1, 2016, and the adoption did not have an impact on the Partnership's consolidated financial position, results of operations and cash flows. Effects on Historical Earnings per Unit of Master Limited Partnership Dropdown Transactions (ASU No. 2015-06) In April 2015, the FASB issued an accounting standard update requiring that the earnings of transferred net assets from a general partner prior to the dropdown date of the net assets to a master limited partnership be allocated entirely to the general partner when calculating earnings per unit under the two class method. As a result, previously reported earnings per unit of the limited partners will not change as a result of a dropdown transaction. The accounting standard is effective for annual periods beginning after December 15, 2015. The Partnership adopted this accounting standard effective January 1, 2016 and the adoption of this accounting standard did not have an impact on the Partnership's consolidated financial position, results of operations and cash flows. Balance Sheet Classification of Deferred Taxes (ASU No. 2015-17) In November 2015, the FASB issued an accounting standards update that requires all deferred tax assets and liabilities, along with any related valuation allowance, to be classified as noncurrent on the balance sheet. As a result, each jurisdiction will now only have one net noncurrent deferred tax asset or liability. The new guidance does not change the existing requirement that only permits offsetting within a jurisdiction. The accounting standard is required to be adopted for reporting periods beginning after December 15, 2016; however, early adoption of this standard is permitted. The Partnership elected to early adopt this accounting standard, to be applied prospectively, effective January 1, 2016. Consistent with the prospective application of this accounting standard, prior period comparative information was not adjusted. The early adoption of this accounting standard did not have an impact on the Partnership's consolidated financial position, results of operations and cash flows.

- Definition

The entire disclosure of changes in accounting principles, including adoption of new accounting pronouncements, that describes the new methods, amount and effects on financial statement line items.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Change in Accounting Principle
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
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+ Details

Accounts Receivable—Third Parties

12 Months Ended

Dec. 31, 2016

Accounts Receivable, Net [Abstract]

Accounts Receivable—Third Parties

Accounts receivable—third parties consist of the following:



	December 31,
	2016			2015
Trade customers	$	11,913		$	12,097
Allowance for doubtful accounts	(564		)	(170		)
	11,349			11,927
Other	736			—
Accounts receivable, net—third parties	$	12,085		$	11,927

Our allowance for doubtful accounts activity during the years ended December 31, 2016, 2015 and 2014 is set forth in the table below:



	Year Ended December 31,
	2016		2015		2014
Balance at January 1	$	170	$	—	$	2,105
Charged to Expense	394		170		65
Deductions ⁽¹⁾	—		—		(2,170		)
Balance at December 31	$	564	$	170	$	—

______________________________

(1) The 2014 deduction represents an adjustment for assets retained by Westlake pursuant to the IPO on August 4, 2014.

- Definition

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.

+ References + Details

Inventories

12 Months Ended

Dec. 31, 2016

Inventory, Net [Abstract]

Inventories

Inventories consist of the following:



	December 31,
	2016		2015
Finished products	$	3,610	$	3,527
Feedstock, additives and chemicals	324		352
Inventories	$	3,934	$	3,879

Property, Plant And Equipment

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment, Net [Abstract]

Property, Plant And Equipment

Property, Plant and Equipment

Property, plant and equipment consist of the following:



	December 31,
	2016			2015
Building and improvements	$	16,757		$	16,124
Plant and equipment	1,690,317			1,231,684
Other	72,215			67,353
	1,779,289			1,315,161
Less: Accumulated depreciation	(644,070		)	(601,980		)
	1,135,219			713,181
Construction in progress	87,019			307,288
Property, plant and equipment, net	$	1,222,238		$	1,020,469

Depreciation expense on property, plant and equipment of $77,444, $64,369 and $60,004 is included in cost of sales in the consolidated and combined statements of operations for the years ended December 31, 2016, 2015 and 2014, respectively.

Other Assets

12 Months Ended

Dec. 31, 2016

Other Assets [Abstract]

Other Assets

Other assets consist of the following:



	December 31, 2016							December 31, 2015
	Cost		Accumulated Amortization			Net		Cost		Accumulated Amortization			Net		Weighted Average Life
Goodwill	$	5,814	$	—		$	5,814	$	5,814	$	—		$	5,814
Deferred charges and other assets
Interest rate contract	290		—			290		436		—			436
Turnaround costs	154,453		(65,268		)	89,185		100,020		(67,767		)	32,253		6
Other	8,723		(3,187		)	5,536		8,710		(2,620		)	6,090		17
Total deferred charges and other assets	163,466		(68,455		)	95,011		109,166		(70,387		)	38,779
Other assets, net	$	169,280	$	(68,455	)	$	100,825	$	114,980	$	(70,387	)	$	44,593

Amortization expense on other assets of $20,766, $16,841 and $17,607 is included in the consolidated and combined statements of operations for the years ended December 31, 2016, 2015 and 2014, respectively.

Goodwill

The impairment test for the recorded goodwill was performed in October 2016 and did not indicate impairment of the goodwill. The fair value of the goodwill was calculated using both a discounted cash flow methodology and a market value methodology. The discounted cash flow projections were based on a nine-year forecast, from 2017 to 2025, to reflect the cyclicality of the Partnership's business. The forecast was based on (1) prices and spreads projected by IHS Chemical, a chemical industry organization offering market and business advisory services for the chemical market, for the same period, and (2) estimates by management, including their strategic and operational plans. Other significant assumptions used in the discounted cash flow projection included sales volumes based on current capacities. The future cash flows were discounted to present value using a discount rate of 8.8%. The significant assumptions used in determining the fair value of the reporting unit using the market value methodology include the determination of appropriate market comparables and the estimated multiples of EBITDA a willing buyer is likely to pay. Under the discounted cash flow methodology, even if the fair value of OpCo decreased by 10%, the carrying value of OpCo would not exceed its fair value.

Long-Term Debt

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Long-Term Debt

Long-term debt consists of the following:



	December 31,
	2016		2015
August 2013 Promissory Notes (variable interest rate of prime plus 1.5%, original scheduled maturity of August 1, 2023)	$	31,775	$	31,775
OpCo Revolver (variable interest rate of London Interbank Offered Rate ("LIBOR") plus 3.0%, original scheduled maturity of August 4, 2019)	427,513		216,890
MLP Revolver (variable interest rate of LIBOR plus 2.0%, original scheduled maturity of April 29, 2018)	135,341		135,341
Long-term debt payable to Westlake	$	594,629	$	384,006

In 2013, the August 2013 Promissory Notes were issued for capital expenditures incurred by Westlake on behalf of the Predecessor's operations. Proceeds drawn under the August 2013 Promissory Notes during 2014 were used to fund capital expenditures at the Predecessor's ethylene plants. In connection with the IPO, OpCo assumed the August 2013 Promissory Notes and used proceeds from the IPO to repay a portion of the balance it assumed. See Note 2 for a description of the August 2013 Promissory Notes and proceeds used to repay balances of such promissory notes assumed in connection with the IPO.

In connection with the IPO on August 4, 2014, OpCo entered into a $600,000 senior unsecured revolving credit facility agreement with Westlake (the "OpCo Revolver"). The OpCo Revolver accrues interest quarterly at a rate of LIBOR plus 3.0%, which may be paid-in-kind as an addition to the principal at OpCo's option. Proceeds drawn under the OpCo Revolver during 2016 were used to fund capital expenditures at OpCo's ethylene plants and to fund the working capital requirements.

On April 29, 2015, the Partnership entered into a $300,000 revolving credit facility agreement with Westlake (the "MLP Revolver") to fund the Partnership's purchase of an additional 2.7% newly-issued, limited partner interest in OpCo for $135,341. Borrowings under the MLP Revolver bear interest at LIBOR plus a spread ranging from 2.0% to 3.0% (depending on the Partnership's consolidated leverage ratio), payable quarterly. The MLP Revolver provides that the Partnership may pay all or a portion of the interest on any borrowings in kind, in which case any such amounts would be added to the principal amount of the loan. The MLP Revolver requires that the Partnership maintain a consolidated leverage ratio of either (1) during any one-year period following certain types of acquisitions (including acquisitions of additional interests in OpCo), 5.50:1.00 or less, or (2) during any other period, 4.50:1.00 or less. The MLP Revolver also contains certain other customary covenants. The repayment of borrowings under the MLP Revolver is subject to acceleration upon the occurrence of an event of default. During August 2015, the Partnership entered into an interest rate contract with Westlake to fix the LIBOR component of the interest rate for a portion of the MLP Revolver balance. The interest rate contract terminates on the earlier of the MLP Revolver maturity date or in August 2018. See Note 14 for additional information on the interest rate contract.

As of December 31, 2016, the Partnership was in compliance with all of the covenants under the August 2013 Promissory Notes, the OpCo Revolver and the MLP Revolver.

The weighted average interest rate on all long-term debt was 3.72% and 3.30% at December 31, 2016 and 2015, respectively.

As of December 31, 2016, the Partnership had no maturities of long-term debt until 2018. The MLP Revolver matures on April 29, 2018, the OpCo Revolver matures on August 4, 2019, and the August 2013 Promissory Notes mature on August 1, 2023.

Distributions and Net Income Per Limited Partner Unit

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Net Income Per Limited Partner Unit

On January 27, 2017, the board of directors of Westlake Chemical Partners GP LLC ("Westlake GP"), the Partnership's general partner, declared a quarterly cash distribution for the period from October 1, 2016 to December 31, 2016 of $0.3450 per unit, and of $142 to the holders of the Partnership's incentive distribution rights ("IDR Holders"). This distribution was paid on February 22, 2017 to unitholders of record on February 7, 2017.

The Partnership Agreement provides that the Partnership will distribute cash each quarter during the subordination period in the following manner: first, to the holders of common units, until each common unit has received the minimum quarterly distribution of $0.2750, plus any arrearages from prior quarters; second, to the holders of subordinated units, until each subordinated unit has received the minimum quarterly distribution of $0.2750; and third, to the holders of common and subordinated units, pro rata, until each unit has received a distribution of $0.3163. If cash distributions to the Partnership's unitholders exceed $0.3163 per common unit and subordinated unit in any quarter, the Partnership's unitholders and Westlake, as the holder of the Partnership's incentive distribution rights, will receive distributions according to the following percentage allocations:



	Marginal Percentage Interest in Distributions
Total Quarterly Distribution Per Unit	Unitholders		IDR Holders
Above $0.3163 up to $0.3438	85.0	%	15.0	%
Above $0.3438 up to $0.4125	75.0	%	25.0	%
Above $0.4125	50.0	%	50.0	%

For the three months ended December 31, 2016, the Partnership's distribution exceeded the $0.3163 per common and subordinated unit target, which resulted in distributions to the IDR Holders.

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



	Year Ended December 31
	2016		2015		2014
Net income attributable to the Partnership	$	40,940	$	39,831	$	13,577
Less:
Limited partners' distribution declared on common units	19,016		16,980		6,403
Limited partners' distribution declared on subordinated units	16,784		14,986		5,649
Distributions declared with respect to the incentive distribution rights	281		—		—
Net income in excess of distribution	$	4,859	$	7,865	$	1,525

Net income per unit applicable to common limited partner units and to subordinated limited partner units is computed by dividing the respective limited partners' interest in net income by the weighted-average number of common units and subordinated units outstanding for the period. Because the Partnership has more than one class of participating securities, it uses the two-class method when calculating the net income per unit applicable to limited partners. The classes of participating securities include common units, subordinated units and incentive distribution rights. Net income attributable to the Partnership is allocated to the unitholders in accordance with their respective ownership percentages in preparation of the consolidated and combined statements of changes in equity. However, when distributions related to the incentive distribution rights are made, net income equal to the amount of those distributions is first allocated to the general partner before the remaining net income is allocated to the unitholders based on their respective ownership percentages. Basic and diluted net income per unit is the same because the Partnership does not have any potentially dilutive units outstanding for the periods presented. Net income per unit is only calculated for the periods subsequent to the IPO as no units were outstanding prior to August 4, 2014.



	December 31, 2016
	Limited Partners' Common Units		Limited Partners' Subordinated Units		Incentive Distribution Rights		Total
Net income attributable to the Partnership:
Distribution	$	19,016	$	16,784	$	281	$	36,081
Net income in excess of distribution	2,581		2,278		—		4,859
Net income	$	21,597	$	19,062	$	281	$	40,940
Weighted average units outstanding:
Basic and diluted	14,373,615		12,686,115				27,059,730
Net income per limited partner unit:
Basic and diluted	$	1.50	$	1.50



	December 31, 2015
	Limited Partners' Common Units		Limited Partners' Subordinated Units		Incentive Distribution Rights		Total
Net income attributable to the Partnership:
Distribution	$	16,980	$	14,986	$	—	$	31,966
Net income in excess of distribution	4,178		3,687		—		7,865
Net income	$	21,158	$	18,673	$	—	$	39,831
Weighted average units outstanding:
Basic and diluted	14,373,615		12,686,115				27,059,730
Net income per limited partner unit:
Basic and diluted	$	1.47	$	1.47



	December 31, 2014
	Limited Partners' Common Units		Limited Partners' Subordinated Units		Incentive Distribution Rights		Total
Net income attributable to the Partnership:
Distribution	$	6,403	$	5,649	$	—	$	12,052
Net income in excess of distribution	810		715		—		1,525
Net income	$	7,213	$	6,364	$	—	$	13,577
Weighted average units outstanding:
Basic and diluted	14,373,615		12,686,115				27,059,730
Net income per limited partner unit:
Basic and diluted	$	0.50	$	0.50

Related Party Transactions

12 Months Ended

Dec. 31, 2016

Related Party Transactions

The Partnership and OpCo regularly enter into related party transactions with Westlake. See below for a description of transactions with related parties.

Sales to Related Parties

OpCo sells ethylene to Westlake under the Ethylene Sales Agreement. Additionally, the Partnership and OpCo from time to time provide other services or products for which it charges Westlake a fee. Prior to the IPO, the Predecessor sold the majority of its ethylene to Westlake for use in Westlake's downstream operations.

Sales to related parties were as follows:



	Year Ended December 31,
	2016		2015		2014
Net sales—Westlake	$	853,719	$	834,918	$	1,292,089

Under the Services and Secondment Agreement, OpCo uses a portion of its production capacity to process purge gas for Westlake. On August 4, 2016, OpCo and Westlake entered into an amendment to the Ethylene Sales Agreement in order to provide that certain of the pricing components that make up the price for ethylene sold thereunder would be modified to reflect the portion of OpCo's production capacity that is used to process Westlake's purge gas instead of producing ethylene and to clarify that costs specific to the processing of Westlake's purge gas would be recovered under the Services and Secondment Agreement, and not the Ethylene Sales Agreement.

Cost of Sales from Related Parties

Charges for goods and services purchased by the Partnership and OpCo from Westlake and included in cost of sales relate primarily to feedstock purchased under the Feedstock Supply Agreement and services provided under the Services and Secondment Agreement. Prior to the IPO, services provided by Westlake and included in cost of sales related primarily to services provided by employees of Westlake Management Services, Inc., a subsidiary of Westlake. The cost of services provided by employees of Westlake Management Services, Inc. was allocated to the Predecessor's operations primarily on the basis of direct usage.

Charges from related parties in cost of sales were as follows:



	Year Ended December 31,
	2016		2015		2014
Feedstock purchased from Westlake and included in cost of sales	$	287,778	$	307,582	$	155,232
Other charges from Westlake and included in cost of sales	85,872		74,050		60,264
Total	$	373,650	$	381,632	$	215,496

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

Charges for services purchased by the Partnership from Westlake and included in selling, general and administrative expenses primarily relate to services Westlake performs on behalf of the Partnership under the Omnibus Agreement, including the Partnership's finance, legal, information technology, human resources, communication, ethics and compliance and other administrative functions. Prior to the IPO, the Predecessor was allocated costs incurred by Westlake on its behalf for similar functions. These allocations were based primarily on the basis of direct usage when identifiable, with the remainder allocated on the basis of fixed assets, headcount or other measure.

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



	Year Ended December 31,
	2016		2015		2014
Services received from Westlake and included in selling, general and administrative expenses	$	21,971	$	20,681	$	21,302

Goods and Services from Related Parties Capitalized as Assets

Charges for goods and services purchased by the Partnership and OpCo from Westlake which were capitalized as assets relate primarily to the services of Westlake employees under the Services and Secondment Agreement. Prior to the IPO, salaries and benefits of Westlake Management Services, Inc. were allocated to the Predecessor primarily on the basis of direct usage.

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



	Year Ended December 31,
	2016		2015		2014
Goods and services purchased from Westlake and capitalized as assets	$	17,874	$	4,332	$	5,823

Accounts Receivable from and Accounts Payable to Related Parties

The Partnership's accounts receivable from Westlake result primarily from ethylene sales to Westlake, the shortfall recoverable from Westlake and a buyer deficiency fee, in each case under the Ethylene Sales Agreement. Under the Ethylene Sales Agreement, if production costs billed to Westlake on an annual basis are less than 95% of the actual production costs incurred by OpCo during the year, OpCo is entitled to recover the shortfall in the subsequent year. The shortfall is recognized in the period when such production activities occur. The shortfall recognized in 2016 is recoverable during 2017, per the Ethylene Sales Agreement. During 2016, Calvert City Olefins experienced a shutdown caused by a mechanical failure, which resulted in a force majeure event under the Ethylene Sales Agreement with Westlake. Based on the annual year-end measurement, a buyer deficiency fee of $13,106 was recognized as a receivable from Westlake and as a component of net sales in the consolidated financial statements as of and for the year ended December 31, 2016. The buyer deficiency fee was collected from Westlake in January 2017.

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

The related party accounts receivable and accounts payable balances were as follows:



	December 31,
	2016		2015
Accounts receivable, net—Westlake	$	126,977	$	39,655
Accounts payable—Westlake	12,130		15,550

Debt Payable to Related Parties

In connection with the IPO, OpCo assumed the August 2013 Promissory Notes and entered into a senior unsecured revolving credit facility with Westlake. In April 2015, the Partnership entered into an unsecured revolving credit facility with Westlake. See Note 8 for a description of related party debt payable balances. Interest on related party debt payable balances, net of capitalized interest, for the years ended December 31, 2016, 2015 and for the period from August 4, 2014 to December 31, 2014 was $12,607, $4,967 and $10,499, respectively, and are reflected as a component of other income (expense) in the consolidated and combined statements of operations. Interest capitalized as a component of property, plant and equipment on related party debt was $5,961 and $5,116 for the years ended December 31, 2016 and 2015, respectively. At December 31, 2016 and 2015, accrued interest on related party debt was $5,517 and $2,879, respectively, and is reflected as a component of accrued liabilities in the consolidated balance sheets.

Debt payable to related parties was as follows:



	December 31,
	2016		2015
Long-term debt payable to Westlake	$	594,629	$	384,006

General

OpCo, together with other subsidiaries of Westlake not included in these consolidated and combined financial statements, were guarantors under Westlake's revolving credit facility and the indentures governing its senior notes. During August 2016, OpCo and certain subsidiaries of Westlake were released from their guarantees.

As of December 31, 2015, Westlake had outstanding letters of credit totaling $30,098 under its revolving credit facility and $754,000 principal amount outstanding under its senior notes (less the unamortized discount and debt issuance costs of$774).

During August 2015, the Partnership entered into an interest rate contract with Westlake to fix the LIBOR component of the interest rate for a portion of the MLP Revolver balance. See Note 14 for additional information on the interest rate contract.

During the years ended December 31, 2016, 2015 and for the period from August 4, 2014 to December 31, 2014, the Partnership reimbursed $245, $1,033 and $0, respectively, to Westlake for certain state tax payments.

OpCo has entered into two site lease agreements with Westlake in connection with the IPO, and each has a term of 50 years. Pursuant to the site lease agreements, OpCo pays Westlake one dollar per site per year.

Partners' Equity	12 Months Ended
Partners' Equity	Dec. 31, 2016
Equity [Abstract]
Partners' Equity	Partners' Equity Common Unit As described below, the common unitholders have preference over subordinated unitholders on receipt of distributions, including, in certain circumstances, cash distributions upon liquidation, as set out in the Partnership's agreement of limited partnership (the "Partnership Agreement"). The common unitholders have limited rights on matters affecting Partnership's business, limited voting rights and are not entitled to elect the general partner or its directors. Subordinated Unit The subordinated unitholders have similar rights as the common unitholders. However, during the subordination period, the subordinated unitholders are not entitled to receive quarterly distributions from operating surplus until the common unitholders have received the minimum quarterly distribution from operating surplus and, among other things, in certain circumstances, are subordinated in the receipt of cash distributions upon liquidation. The subordination period will end on the first business day after the Partnership has earned and paid an aggregate amount of at least the minimum quarterly distribution multiplied by the total number of outstanding common and subordinated units for each of three consecutive, non-overlapping four-quarter periods ending on or after June 30, 2017, and there are no outstanding arrearages on the Partnership's common units. Notwithstanding the foregoing, the subordination period will end on the first business day after the Partnership has paid an aggregate amount of at least 150.0% of the minimum quarterly distribution on an annualized basis multiplied by the total number of outstanding common and subordinated units and have earned that amount plus the related distribution on the incentive distribution rights, for any four-quarter period ending on or after June 30, 2015, and there are no outstanding arrearages on Partnership's common units.

Accumulated Other Comprehensive Income

12 Months Ended

Dec. 31, 2016

Equity [Abstract]

Accumulated Other Comprehensive Income

Accumulated other comprehensive income or loss primarily reflects the effective portion of the gain or loss on derivative instrument designated and qualified as a cash flow hedge. Gain or loss amounts related to a cash flow hedge recorded in accumulated other comprehensive income or loss are reclassified to income in the same period in which the underlying hedged forecasted transaction affects income. If it becomes probable that a forecasted transaction will not occur, the related net gain or loss in accumulated other comprehensive income or loss is immediately reclassified into income.

Changes in accumulated other comprehensive income was as follows:



	Year Ended December 31,
	2016			2015
Balance at January 1	$	280		$	—
Interest rate contract - Other comprehensive income before reclassifications	(416		)	85
Interest rate contract - Amounts reclassified to net income	336			195
Balance at December 31	$	200		$	280

- Definition

The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e689-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
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-Section 45
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-URI http://asc.fasb.org/extlink&oid=66004124&loc=SL7669619-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Paragraph 1
-Subparagraph (SX 210.3-04)
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Reclassification Adjustments
-URI http://asc.fasb.org/extlink&oid=6522872

+ Details

Unit-Based Compensation

12 Months Ended

Dec. 31, 2016

Share-based Compensation [Abstract]

Unit-Based Compensation

Unit-based Compensation

The Westlake Chemical Partners LP Long-Term Incentive Plan (the "Plan") was adopted on July 15, 2014 and provides for grants of unit options, restricted units, phantom units, unit awards, distribution equivalent rights ("DERs") and other unit-based awards. The purpose of the Plan is to attract and retain the services of individuals who are essential for the growth and profitability of the Partnership and to encourage such individuals to devote their best efforts to advancing the business of the Partnership and its affiliates. Awards under the Plan are determined by the board of directors of the Partnership's general partner or a committee thereof (the "Committee"). Under the Plan, DERs may be granted, which represent a contingent right to receive an amount in cash, units, restricted units and/or phantom units, as determined by the Committee at its sole discretion, equal in value to the cash distributions made by the Partnership with respect to a common unit during the period such award is outstanding. The terms and conditions of each award are determined by the Committee. The maximum number of common units of the Partnership that may be delivered with respect to awards under the Plan is 1,270,000. The phantom units along with a corresponding number of DERs were granted to certain non-employee directors of the general partner of the Partnership during the years ended December 31, 2016, 2015 and the period from August 4, 2014 through December 31, 2014. These phantom units vest on the third anniversary of the grant date. There were no forfeitures under the Plan during 2016, 2015 and the period from August 4, 2014 through December 31, 2014. During 2016, the vesting of 5,543 phantom units was accelerated in connection with the retirement of one of our non-employee directors. The total fair value of phantom units that vested during the year ended December 31, 2016 was $123,221.

Non-vested phantom unit awards as of December 31, 2016 and 2015 and awards granted during the respective periods were as follows:



	Number of Units		Weighted Average Fair Value
Non-vested balance at December 31, 2014	4,404		$	29.49
Granted	12,559		20.57
Non-vested balance at December 31, 2015	16,963		22.89
Granted	9,900		22.91
Vested	(5,543	)	23.38
Non-vested balance at December 31, 2016	21,320		22.77

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

The awards, which are classified as liability awards for financial accounting purposes, are re-measured at each reporting date until they vest. The total units available for grant at December 31, 2016 were 1,248,680. The total compensation cost recognized during the years ended December 31, 2016, 2015 and for the period from August 4, 2014 through December 31, 2014 was $194, $75 and $15, respectively, and is included in selling, general and administrative expenses and classified as a liability in the consolidated and combined financial statements of the Partnership. The unrecognized compensation cost associated with all grants under the Plan at December 31, 2016 was $300,296 and the weighted average remaining term of the units at December 31, 2016 was 1.96 years.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

Derivative Instruments

12 Months Ended

Dec. 31, 2016

Derivative Instruments and Hedges, Assets [Abstract]

Derivative Instruments

Commodity Risk Management

The Predecessor used derivative instruments to reduce price volatility risk on raw materials and products, as a substantial portion of its raw materials and products were commodities whose prices fluctuate as market supply and demand fundamentals change. The Predecessor employed strategies to protect against such instability, including ethylene product feedstock flexibility. The Predecessor did not use derivative instruments to engage in speculative activities. The Contributed Assets did not include the entity engaged in commodity risk management activities or any of its open derivative positions. The Partnership has not engaged in any hedging activity and did not use any derivative instruments related to the commodities in the period subsequent to the IPO through December 31, 2014 or during the years ended December 31, 2015 and 2016.

For derivative instruments that are designated and qualify as fair value hedges, the gains or losses on the derivative instruments, as well as the offsetting losses or gains on the hedged items attributable to the hedged risk, are included in cost of sales in the consolidated and combined statements of operations. There were no derivative instruments that were designated as fair value hedges for the years ended December 31, 2016 and 2015.

Gains and losses from changes in the fair value of derivative instruments that are not designated as hedging instruments were included in gross profit in the consolidated and combined statements of operations for the years ended December 31, 2015 and 2014. The Partnership had no derivative instruments that were not designated as hedging instruments subsequent to the IPO through December 31, 2014, or during 2015 and 2016. The impact of derivative instruments that have not been designated as hedges in the consolidated and combined statements of operations for the year ended December 31, 2014 was as follows:

There was no open derivative position related to commodities at December 31, 2016 or 2015.

Interest Rate Risk Management

During August 2015, the Partnership entered into an interest rate contract with Westlake designed to reduce the risks of variability of the interest rate under the MLP Revolver. The interest rate contract fixed the LIBOR component of the interest rate for a portion of the MLP Revolver balance. This contract was designated as a cash flow hedge. With the exception of this interest rate contract, the Partnership did not have any other derivative financial instruments during the years ended December 31, 2016 and 2015. For the year ended December 31, 2014, neither the Partnership nor the Predecessor had any interest rate contracts.

The fair value of the derivative instrument on the Partnership's consolidated balance sheet as of December 31, 2016 and 2015 was as follows:



	Derivative Asset
Derivative in Cash Flow Hedging Relationship	Balance Sheet Location	Fair Value as of December 31, 2016		Fair Value as of December 31, 2015
Interest rate contract	Deferred charges and other assets, net	$	290	$	436

The following tables present the effect of the derivative instrument designated as cash flow hedge on the consolidated statements of operations and the consolidated statements of comprehensive income for the years ended December 31, 2016 and 2015:



Derivative in Cash Flow Hedging Relationship	Location of Gain (Loss) Recognized in Statement of Operations	Year Ended December 31, 2016			Year Ended December 31, 2015
Interest rate contract—Loss reclassified from accumulated other comprehensive income to net income	Interest expense	$	(336	)	$	(195	)



Derivative in Cash Flow Hedging Relationship	Year Ended December 31, 2016			Year Ended December 31, 2015
Derivative in Cash Flow Hedging Relationship	Year Ended December 31, 2016			Year Ended December 31, 2015
Interest rate contract—Adjustments to fair value recognized in other comprehensive income	$	(416	)	$	85

There was no material ineffectiveness with regard to the Partnership and Predecessor's qualifying hedges for the years ended December 31, 2016, 2015 and 2014.

See Note 15 for the fair value of derivative instruments.

- Definition

The entire disclosure for derivative instruments and hedging activities including, but not limited to, risk management strategies, non-hedging derivative instruments, assets, liabilities, revenue and expenses, and methodologies and assumptions used in determining the amounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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+ Details

Fair Value Measurements

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Fair Value Measurements

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

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

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

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

The following table summarizes, by level within the fair value hierarchy, the Partnership's asset under the interest rate contract that was accounted for at fair value on a recurring basis at December 31, 2016.



	December 31, 2016
	Level 2		Total
Derivative instruments
Asset—Interest rate contract	$	290	$	290



	December 31, 2015
	Level 2		Total
Derivative instruments
Asset—Interest rate contract	$	436	$	436

The fair value of the Level 2 interest rate contract is determined using standard valuation methodologies which incorporate relevant contract terms along with readily available market data (i.e. the 3 month LIBOR forward curve). There were no transfers in and out of Levels 1 and 2 of the fair value hierarchy during 2016.

In addition to the above, the Partnership has other financial assets and liabilities subject to fair value measures. These financial assets and liabilities include cash and cash equivalents, accounts receivable, net, accounts payable and long-term debt payable to Westlake, all of which are recorded at carrying value. The amounts reported in the consolidated balance sheets for accounts receivable, net and accounts payable approximate their fair value due to the short maturities of these instruments. The carrying and fair values of the Partnership's long-term debt at December 31, 2016 and December 31, 2015 are summarized in the table below. The Partnership's long-term debt includes the August 2013 Promissory Notes, the OpCo Revolver and the MLP Revolver. The fair value of debt is determined based on the present value of expected future cash flows using a discounted cash flow methodology. Because the Partnership's valuation methodology used for long-term debt requires the use of significant unobservable inputs, the inputs used to measure the fair value of the Partnership's long-term debt are classified as Level 3 within the fair value hierarchy. Inputs used to estimate the fair values of the Partnership's long-term debt include the selection of an appropriate discount rate.



	December 31, 2016				December 31, 2015
	Carrying Value		Fair Value		Carrying Value	Fair Value
August 2013 Promissory Notes	$	31,775	$	31,775	31,775	31,775
OpCo Revolver	427,513		442,716		216,890	215,738
MLP Revolver	135,341		134,835		135,341	130,439

- Definition

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

+ References + Details

Income Taxes

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Income Taxes

The components of income tax disaggregated between the Partnership and the Predecessor are as follows:



	Partnership							Predecessor
	Year Ended December 31, 2016		Year Ended December 31, 2015			Period from August 4, 2014 to December 31, 2014		Period from January 1, 2014 to August 3, 2014
Current
Federal	$	—	$	—		$	—	$	168,773
State and local	691		1,128			800		21,207
	691		1,128			800		189,980
Deferred
Federal	—		—			—		6,890
State and local	344		(456		)	265		1,453
	344		(456		)	265		8,343
Total provision	$	1,035	$	672		$	1,065	$	198,323

The reconciliation of income tax expense at the U.S. statutory rate to the income tax expense disaggregated between the Partnership and the Predecessor is as follows:



	Partnership									Predecessor
	Year Ended December 31, 2016			Year Ended December 31, 2015			Period from August 4, 2014 to December 31, 2014			Period from January 1, 2014 to August 3, 2014
Provision for federal income tax, at statutory rate	$	124,054		$	124,083		$	52,343		$	195,880
State income tax provision, net of federal income tax effect	1,035			672			1,065			14,729
Partnership income not subject to entity-level federal income tax	(124,054		)	(124,083		)	(52,343		)	—
Manufacturing deduction	—			—			—			(12,214		)
Other, net	—			—			—			(72		)
Total provision	$	1,035		$	672		$	1,065		$	198,323

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



	December 31,
	2016			2015
Property, plant and equipment	$	(1,488	)	$	(1,291	)
Turnaround costs	(248		)	(101		)
Total deferred tax liabilities	$	(1,736	)	$	(1,392	)

Balance sheet classifications
Noncurrent deferred tax liability	$	(1,736	)	$	(1,392	)
Total deferred tax liabilities	$	(1,736	)	$	(1,392	)

Supplemental Information	12 Months Ended
Supplemental Information	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Information	Supplemental Information Accrued Liabilities Accrued liabilities were $15,717 and $23,407 at December 31, 2016 and 2015, respectively. Accruals related to accrued interest, capital expenditures, and maintenance expenses, which are components of accrued liabilities, were $5,517, $2,647 and $2,586 at December 31, 2016, respectively, and were $2,879, $14,745 and $2,949 at December 31, 2015, respectively. No other component of accrued liabilities was more than five percent of total current liabilities. Cash Flow Information Non-cash Operating Activity The Predecessor settled $9,315 of its total interest expense incurred on long-term debt payable to Westlake as an addition to principal on debt outstanding in 2014. Non-cash Investing Activity The change in capital expenditure accrual increasing additions to property, plant and equipment was $18,113 for the year ended December 31, 2016 and the change in capital expenditure accrual reducing additions to property, plant and equipment was $14,552 and $418 for the years ended December 31, 2015 and 2014, respectively. Non-cash Financing Activity Related party notes payable to Westlake of $238,600 were deemed settled through net investment in 2014. The non-cash settlement was recorded as an increase in Westlake's net investment in the Predecessor. No cash was transferred in connection with the deemed settlement of these notes. Interest and Income Taxes Interest paid by the Partnership, net of interest capitalized, was $9,901, $9,538 and $1,366 for the years ended December 31, 2016, 2015 and 2014, respectively. Income tax paid by the Partnership was $633 and $1,264 for the years ended December 31, 2016 and 2015, respectively, of which $388 and $231 was paid directly to the tax authorities for the years ended December 31, 2016 and 2015, and $245 and $1,033 was paid to Westlake as reimbursements for the years ended December 31, 2016 and 2015. No income tax payments were made during 2014 by the Partnership.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2016

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

The Partnership is subject to environmental laws and regulations that can impose civil and criminal sanctions and that may require the Partnership to mitigate the effects of contamination caused by the release or disposal of hazardous substances into the environment. These laws include the federal Clean Air Act, the federal Water Pollution Control Act, the Resource Conservation and Recovery Act ("RCRA"), the Comprehensive Environmental Response, Compensation, and Liability Act ("CERCLA"), the Toxic Substances Control Act and various other federal, state and local laws and regulations. Under CERCLA, an owner or operator of property may be held strictly liable for remediating contamination without regard to whether that person caused the contamination, and without regard to whether the practices that resulted in the contamination were legal at the time they occurred. Because the Partnership's production sites have a history of industrial use, it is impossible to predict precisely what effect these legal requirements will have on the Partnership. Westlake will indemnify the Partnership for liabilities that occurred or existed prior to August 4, 2014.

Potential Flare Modifications. For several years, the EPA has been conducting an enforcement initiative against petroleum refineries and petrochemical plants with respect to emissions from flares. On April 21, 2014, Westlake received a Clean Air Act Section 114 Information Request from the EPA which sought information regarding flares at the Calvert City and Lake Charles facilities. The EPA has informed Westlake that the information provided leads the EPA to believe that some of the flares are out of compliance with applicable standards. The EPA has indicated that it is seeking a consent decree with that would obligate Westlake to take corrective actions relating to the alleged noncompliance. Westlake believes the resolution of these matters may require the payment of a monetary sanction in excess of $100.

Louisiana Notice of Violations. The Louisiana Department of Environmental Quality ("LDEQ") has issued notices of violations ("NOVs") regarding the Partnership's assets, and those of Westlake, for various air compliance issues. The Partnership and Westlake are working with LDEQ to settle these claims, and a global settlement of all claims is being discussed. Westlake has reached a verbal agreement with the LDEQ to settle various NOVs in two separate settlements for a combined $192 in civil penalties.

In addition to the matters described above, the Partnership is involved in various legal proceedings incidental to the conduct of its business. The Partnership does not believe that any of these legal proceedings will have a material adverse effect on its financial condition, results of operations or cash flows.

Other Commitments

The Partnership is obligated under various long-term and short-term noncancelable operating leases, primarily related to rail car leases and land. Several of the leases provide for renewal terms. At December 31, 2016, future minimum lease commitments were as follows:



2017	$	1,144
2018	907
2019	839
2020	771
2021	656
Thereafter	383
	$	4,700

Rental expense was approximately $2,542, $3,125 and $3,558 for the years ended December 31, 2016, 2015 and 2014, respectively.

The Partnership has various purchase commitments for its capital projects and for materials, supplies and services incident to the ordinary conduct of business.

Major Customer and Concentration Risk	12 Months Ended
Major Customer and Concentration Risk	Dec. 31, 2016
Risks and Uncertainties [Abstract]
Major Customer and Concentration of Credit Risk	Major Customer and Concentration of Credit Risk During the years ended December 31, 2016, 2015 and 2014, Westlake accounted for approximately 86.5%, 82.9% and 73.8%, respectively, of the Partnership's and the Predecessor's net sales.

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Distribution On January 27, 2017, the Board of Directors of the Partnership's general partner announced a quarterly distribution for the period from October 1, 2016 through December 31, 2016 of $0.3450 per unit and $142 to IDR Holders, which was paid on February 22, 2017 to unitholders of record as of February 7, 2017. General Subsequent events were evaluated through the date on which the financial statements were issued.

Quarterly Financial Information (Unaudited)

12 Months Ended

Dec. 31, 2016

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information (Unaudited)



	Three Months Ended
	March 31, 2016		June 30, 2016		September 30, 2016		December 31, 2016
Net sales	$	252,604	$	210,841	$	229,354	$	293,937
Gross profit	110,414		88,381		86,801		105,735
Income from operations	104,317		82,533		81,013		98,581
Net income	102,771		81,192		75,859		93,581
Net income attributable to Westlake Chemical Partners LP	12,084		9,344		8,661		10,851
Net income attributable to Westlake Chemical Partners LP
Basic and diluted earnings per common unitholder	$	0.45	$	0.34	$	0.32	$	0.39
Basic and diluted earnings per subordinated unitholder	$	0.45	$	0.34	$	0.32	$	0.39

	Three Months Ended
	March 31, 2015		June 30, 2015		September 30, 2015		December 31, 2015

Net sales	$	258,391	$	251,705	$	248,619	$	248,506
Gross profit	96,227		94,528		94,145		97,982
Income from operations	90,227		88,533		88,314		92,258
Net income	88,389		87,243		87,046		91,175
Net income attributable to Westlake Chemical Partners LP	8,500		10,443		10,103		10,785
Net income attributable to Westlake Chemical Partners LP
Basic and diluted earnings per common unitholder	$	0.31	$	0.39	$	0.37	$	0.40
Basic and diluted earnings per subordinated unitholder	$	0.31	$	0.39	$	0.37	$	0.40

Description Of Business And Significant Accounting Policies (Policy)

12 Months Ended

Dec. 31, 2016

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Description Of Business

Description of Business

Basis of Presentation

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


•	The consolidated statement of operations for the year ended December 31, 2014 consists of the consolidated results of the Partnership for the period from August 4, 2014 through December 31, 2014 and the combined results of the Predecessor for the period from January 1, 2014 through August 3, 2014.


•	The consolidated statement of cash flows for the year ended December 31, 2014 consists of the consolidated results of the Partnership for the period from August 4, 2014 through December 31, 2014 and the combined results of the Predecessor for the period from January 1, 2014 through August 3, 2014.

•

Cash And Cash Equivalents

Cash and Cash Equivalents

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

Allowance For Doubtful Accounts

Allowance for Doubtful Accounts

Inventories

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

Property, Plant and Equipment

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



Classification		Years

Buildings and improvements		25
Plant and equipment		25
Ethylene pipeline		35
Other		3-10

Impairment Of Long-Lived Assets and Intangible Assets

Impairment of Long-Lived Assets

Impairment of Goodwill and Intangible Assets

Turnaround Costs

Exchanges

Concentration Of Credit Risk

Concentration of Credit Risk

Revenue Recognition

Net Income per Unit

Derivative Instruments

Environmental Costs

Fair Value Of Financial Instruments

Fair Value of Financial Instruments

Use of Estimates

Certain other assets (see Note 7) are amortized over periods ranging from five to 15 years using the straight-line method.

Comprehensive Income

Other Comprehensive Income

The Partnership has reported no comprehensive income for the year ended December 31, 2014 due to the absence of items of other comprehensive income.

Description Of Business And Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Property, Plant and Equipment

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



Classification		Years

Buildings and improvements		25
Plant and equipment		25
Ethylene pipeline		35
Other		3-10

Schedule Of Estimated Useful Lives Of Assets

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



Classification		Years

Buildings and improvements		25
Plant and equipment		25
Ethylene pipeline		35
Other		3-10

Accounts Receivable—Third Parties (Tables)

12 Months Ended

Dec. 31, 2016

Accounts Receivable, Net [Abstract]

Schedule Of Accounts Receivable

Accounts receivable—third parties consist of the following:



	December 31,
	2016			2015
Trade customers	$	11,913		$	12,097
Allowance for doubtful accounts	(564		)	(170		)
	11,349			11,927
Other	736			—
Accounts receivable, net—third parties	$	12,085		$	11,927

Our allowance for doubtful accounts activity during the years ended December 31, 2016, 2015 and 2014 is set forth in the table below:



	Year Ended December 31,
	2016		2015		2014
Balance at January 1	$	170	$	—	$	2,105
Charged to Expense	394		170		65
Deductions ⁽¹⁾	—		—		(2,170		)
Balance at December 31	$	564	$	170	$	—

______________________________

(1) The 2014 deduction represents an adjustment for assets retained by Westlake pursuant to the IPO on August 4, 2014.

Inventories (Tables)

12 Months Ended

Dec. 31, 2016

Inventory, Net [Abstract]

Schedule Of Inventory

Inventories consist of the following:



	December 31,
	2016		2015
Finished products	$	3,610	$	3,527
Feedstock, additives and chemicals	324		352
Inventories	$	3,934	$	3,879

Property, Plant And Equipment (Tables)

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment, Net [Abstract]

Schedule Of Property, Plant And Equipment

Property, plant and equipment consist of the following:



	December 31,
	2016			2015
Building and improvements	$	16,757		$	16,124
Plant and equipment	1,690,317			1,231,684
Other	72,215			67,353
	1,779,289			1,315,161
Less: Accumulated depreciation	(644,070		)	(601,980		)
	1,135,219			713,181
Construction in progress	87,019			307,288
Property, plant and equipment, net	$	1,222,238		$	1,020,469

Other Assets (Tables)

12 Months Ended

Dec. 31, 2016

Other Assets [Abstract]

Schedule Of Other Assets

Other assets consist of the following:



	December 31, 2016							December 31, 2015
	Cost		Accumulated Amortization			Net		Cost		Accumulated Amortization			Net		Weighted Average Life
Goodwill	$	5,814	$	—		$	5,814	$	5,814	$	—		$	5,814
Deferred charges and other assets
Interest rate contract	290		—			290		436		—			436
Turnaround costs	154,453		(65,268		)	89,185		100,020		(67,767		)	32,253		6
Other	8,723		(3,187		)	5,536		8,710		(2,620		)	6,090		17
Total deferred charges and other assets	163,466		(68,455		)	95,011		109,166		(70,387		)	38,779
Other assets, net	$	169,280	$	(68,455	)	$	100,825	$	114,980	$	(70,387	)	$	44,593

Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Schedule Of Long-Term Debt

Long-term debt consists of the following:



	December 31,
	2016		2015
August 2013 Promissory Notes (variable interest rate of prime plus 1.5%, original scheduled maturity of August 1, 2023)	$	31,775	$	31,775
OpCo Revolver (variable interest rate of London Interbank Offered Rate ("LIBOR") plus 3.0%, original scheduled maturity of August 4, 2019)	427,513		216,890
MLP Revolver (variable interest rate of LIBOR plus 2.0%, original scheduled maturity of April 29, 2018)	135,341		135,341
Long-term debt payable to Westlake	$	594,629	$	384,006

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21538-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
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-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28541-108399

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644

+ Details

Distributions and Net Income Per Limited Partner Unit (Tables)

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Schedule of Incentive Distributions Made to Managing Members or General Partners by Distribution

If cash distributions to the Partnership's unitholders exceed $0.3163 per common unit and subordinated unit in any quarter, the Partnership's unitholders and Westlake, as the holder of the Partnership's incentive distribution rights, will receive distributions according to the following percentage allocations:



	Marginal Percentage Interest in Distributions
Total Quarterly Distribution Per Unit	Unitholders		IDR Holders
Above $0.3163 up to $0.3438	85.0	%	15.0	%
Above $0.3438 up to $0.4125	75.0	%	25.0	%
Above $0.4125	50.0	%	50.0	%

Schedule of Earnings Per Share, Basic and Diluted



	Year Ended December 31
	2016		2015		2014
Net income attributable to the Partnership	$	40,940	$	39,831	$	13,577
Less:
Limited partners' distribution declared on common units	19,016		16,980		6,403
Limited partners' distribution declared on subordinated units	16,784		14,986		5,649
Distributions declared with respect to the incentive distribution rights	281		—		—
Net income in excess of distribution	$	4,859	$	7,865	$	1,525



	December 31, 2016
	Limited Partners' Common Units		Limited Partners' Subordinated Units		Incentive Distribution Rights		Total
Net income attributable to the Partnership:
Distribution	$	19,016	$	16,784	$	281	$	36,081
Net income in excess of distribution	2,581		2,278		—		4,859
Net income	$	21,597	$	19,062	$	281	$	40,940
Weighted average units outstanding:
Basic and diluted	14,373,615		12,686,115				27,059,730
Net income per limited partner unit:
Basic and diluted	$	1.50	$	1.50



	December 31, 2015
	Limited Partners' Common Units		Limited Partners' Subordinated Units		Incentive Distribution Rights		Total
Net income attributable to the Partnership:
Distribution	$	16,980	$	14,986	$	—	$	31,966
Net income in excess of distribution	4,178		3,687		—		7,865
Net income	$	21,158	$	18,673	$	—	$	39,831
Weighted average units outstanding:
Basic and diluted	14,373,615		12,686,115				27,059,730
Net income per limited partner unit:
Basic and diluted	$	1.47	$	1.47



	December 31, 2014
	Limited Partners' Common Units		Limited Partners' Subordinated Units		Incentive Distribution Rights		Total
Net income attributable to the Partnership:
Distribution	$	6,403	$	5,649	$	—	$	12,052
Net income in excess of distribution	810		715		—		1,525
Net income	$	7,213	$	6,364	$	—	$	13,577
Weighted average units outstanding:
Basic and diluted	14,373,615		12,686,115				27,059,730
Net income per limited partner unit:
Basic and diluted	$	0.50	$	0.50

Related Party Transactions (Tables)

12 Months Ended

Dec. 31, 2016

Schedule of Related Party Transactions

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



	Year Ended December 31,
	2016		2015		2014
Services received from Westlake and included in selling, general and administrative expenses	$	21,971	$	20,681	$	21,302

Sales to related parties were as follows:



	Year Ended December 31,
	2016		2015		2014
Net sales—Westlake	$	853,719	$	834,918	$	1,292,089

Debt payable to related parties was as follows:



	December 31,
	2016		2015
Long-term debt payable to Westlake	$	594,629	$	384,006

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



	Year Ended December 31,
	2016		2015		2014
Goods and services purchased from Westlake and capitalized as assets	$	17,874	$	4,332	$	5,823

Charges from related parties in cost of sales were as follows:



	Year Ended December 31,
	2016		2015		2014
Feedstock purchased from Westlake and included in cost of sales	$	287,778	$	307,582	$	155,232
Other charges from Westlake and included in cost of sales	85,872		74,050		60,264
Total	$	373,650	$	381,632	$	215,496

The related party accounts receivable and accounts payable balances were as follows:



	December 31,
	2016		2015
Accounts receivable, net—Westlake	$	126,977	$	39,655
Accounts payable—Westlake	12,130		15,550

Accumulated Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2016

Equity [Abstract]

Schedule of Accumulated Other Comprehensive Income

Changes in accumulated other comprehensive income was as follows:



	Year Ended December 31,
	2016			2015
Balance at January 1	$	280		$	—
Interest rate contract - Other comprehensive income before reclassifications	(416		)	85
Interest rate contract - Amounts reclassified to net income	336			195
Balance at December 31	$	200		$	280

Unit-Based Compensation Nonvested phantom units (Tables)

12 Months Ended

Dec. 31, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Nonvested Restricted Stock Units Activity

Non-vested phantom unit awards as of December 31, 2016 and 2015 and awards granted during the respective periods were as follows:



	Number of Units		Weighted Average Fair Value
Non-vested balance at December 31, 2014	4,404		$	29.49
Granted	12,559		20.57
Non-vested balance at December 31, 2015	16,963		22.89
Granted	9,900		22.91
Vested	(5,543	)	23.38
Non-vested balance at December 31, 2016	21,320		22.77

Derivative Instruments (Tables)

12 Months Ended

Dec. 31, 2016

Derivative Instruments and Hedges, Assets [Abstract]

Impact Of Derivative Instruments Not Designated As Fair Value Hedges

The impact of derivative instruments that have not been designated as hedges in the consolidated and combined statements of operations for the year ended December 31, 2014 was as follows:

Fair Values Of Derivative Instruments In Consolidated Balance Sheets

The fair value of the derivative instrument on the Partnership's consolidated balance sheet as of December 31, 2016 and 2015 was as follows:



	Derivative Asset
Derivative in Cash Flow Hedging Relationship	Balance Sheet Location	Fair Value as of December 31, 2016		Fair Value as of December 31, 2015
Interest rate contract	Deferred charges and other assets, net	$	290	$	436

Derivative Instruments, Gain (Loss)



Derivative in Cash Flow Hedging Relationship	Location of Gain (Loss) Recognized in Statement of Operations	Year Ended December 31, 2016			Year Ended December 31, 2015
Interest rate contract—Loss reclassified from accumulated other comprehensive income to net income	Interest expense	$	(336	)	$	(195	)



Derivative in Cash Flow Hedging Relationship	Year Ended December 31, 2016			Year Ended December 31, 2015
Derivative in Cash Flow Hedging Relationship	Year Ended December 31, 2016			Year Ended December 31, 2015
Interest rate contract—Adjustments to fair value recognized in other comprehensive income	$	(416	)	$	85

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Schedule Of Assets And Liabilities On A Recurring Basis



	December 31, 2016
	Level 2		Total
Derivative instruments
Asset—Interest rate contract	$	290	$	290



	December 31, 2015
	Level 2		Total
Derivative instruments
Asset—Interest rate contract	$	436	$	436

Schedule Of Carrying And Fair Values Of Long-Term Debt

The carrying and fair values of the Partnership's long-term debt at December 31, 2016 and December 31, 2015 are summarized in the table below. The Partnership's long-term debt includes the August 2013 Promissory Notes, the OpCo Revolver and the MLP Revolver. The fair value of debt is determined based on the present value of expected future cash flows using a discounted cash flow methodology. Because the Partnership's valuation methodology used for long-term debt requires the use of significant unobservable inputs, the inputs used to measure the fair value of the Partnership's long-term debt are classified as Level 3 within the fair value hierarchy. Inputs used to estimate the fair values of the Partnership's long-term debt include the selection of an appropriate discount rate.



	December 31, 2016				December 31, 2015
	Carrying Value		Fair Value		Carrying Value	Fair Value
August 2013 Promissory Notes	$	31,775	$	31,775	31,775	31,775
OpCo Revolver	427,513		442,716		216,890	215,738
MLP Revolver	135,341		134,835		135,341	130,439

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Schedule Of The Provision For (Benefit From) Income Taxes

The components of income tax disaggregated between the Partnership and the Predecessor are as follows:



	Partnership							Predecessor
	Year Ended December 31, 2016		Year Ended December 31, 2015			Period from August 4, 2014 to December 31, 2014		Period from January 1, 2014 to August 3, 2014
Current
Federal	$	—	$	—		$	—	$	168,773
State and local	691		1,128			800		21,207
	691		1,128			800		189,980
Deferred
Federal	—		—			—		6,890
State and local	344		(456		)	265		1,453
	344		(456		)	265		8,343
Total provision	$	1,035	$	672		$	1,065	$	198,323

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

The reconciliation of income tax expense at the U.S. statutory rate to the income tax expense disaggregated between the Partnership and the Predecessor is as follows:



	Partnership									Predecessor
	Year Ended December 31, 2016			Year Ended December 31, 2015			Period from August 4, 2014 to December 31, 2014			Period from January 1, 2014 to August 3, 2014
Provision for federal income tax, at statutory rate	$	124,054		$	124,083		$	52,343		$	195,880
State income tax provision, net of federal income tax effect	1,035			672			1,065			14,729
Partnership income not subject to entity-level federal income tax	(124,054		)	(124,083		)	(52,343		)	—
Manufacturing deduction	—			—			—			(12,214		)
Other, net	—			—			—			(72		)
Total provision	$	1,035		$	672		$	1,065		$	198,323

Schedule Of Deferred Tax Assets And Liabilities

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



	December 31,
	2016			2015
Property, plant and equipment	$	(1,488	)	$	(1,291	)
Turnaround costs	(248		)	(101		)
Total deferred tax liabilities	$	(1,736	)	$	(1,392	)

Balance sheet classifications
Noncurrent deferred tax liability	$	(1,736	)	$	(1,392	)
Total deferred tax liabilities	$	(1,736	)	$	(1,392	)

Commitments And Contingencies (Tables)

12 Months Ended

Dec. 31, 2016

Commitments and Contingencies Disclosure [Abstract]

Future Minimum Lease Commitments

At December 31, 2016, future minimum lease commitments were as follows:



2017	$	1,144
2018	907
2019	839
2020	771
2021	656
Thereafter	383
	$	4,700

Quarterly Financial Information (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2016

Quarterly Financial Information Disclosure [Abstract]

Summary Of Quarterly Financial Information



	Three Months Ended
	March 31, 2016		June 30, 2016		September 30, 2016		December 31, 2016
Net sales	$	252,604	$	210,841	$	229,354	$	293,937
Gross profit	110,414		88,381		86,801		105,735
Income from operations	104,317		82,533		81,013		98,581
Net income	102,771		81,192		75,859		93,581
Net income attributable to Westlake Chemical Partners LP	12,084		9,344		8,661		10,851
Net income attributable to Westlake Chemical Partners LP
Basic and diluted earnings per common unitholder	$	0.45	$	0.34	$	0.32	$	0.39
Basic and diluted earnings per subordinated unitholder	$	0.45	$	0.34	$	0.32	$	0.39

	Three Months Ended
	March 31, 2015		June 30, 2015		September 30, 2015		December 31, 2015

Net sales	$	258,391	$	251,705	$	248,619	$	248,506
Gross profit	96,227		94,528		94,145		97,982
Income from operations	90,227		88,533		88,314		92,258
Net income	88,389		87,243		87,046		91,175
Net income attributable to Westlake Chemical Partners LP	8,500		10,443		10,103		10,785
Net income attributable to Westlake Chemical Partners LP
Basic and diluted earnings per common unitholder	$	0.31	$	0.39	$	0.37	$	0.40
Basic and diluted earnings per subordinated unitholder	$	0.31	$	0.39	$	0.37	$	0.40

Description Of Business And Significant Accounting Policies (Narrative) (Details)				12 Months Ended
	Apr. 29, 2015 USD ($)	Apr. 01, 2015	Aug. 04, 2014 production_facility shares	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest				$ 353,323,000	$ 354,133,000	$ 0
Threshold period past due accounts receivable reviewed				90 days
Capitalized interest				$ 5,961,000	5,116,000	$ 2,638,000
Goodwill				$ 5,814,000	$ 5,814,000
Amortization period, minimum (in years)				3 years
Amortization period, maximum (in years)				6 years
Other assets amortization period, minimum (in years)				5 years
Other assets amortization period, maximum (in years)				15 years
Affiliated Entity [Member] \| Westlake [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Capitalized interest				$ 5,961,000
Affiliated Entity [Member] \| Westlake Chemical OpCo LP [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Partnership's ownership interest (percent)		13.30%	10.60%
Additional ownership interest acquired	2.70%	2.70%	4.80%
Amount paid to purchase additional limited partner interest	$ 135,341,000
Limited Liability Company [Member] \| Westlake Chemical OpCo GP LLC [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Partnership's ownership interest (percent)			100.00%
Westlake [Member] \| Majority-Owned Subsidiary, Unconsolidated [Member] \| Westlake Chemical OpCo LP [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Partnership's ownership interest (percent)		86.70%
Westlake Chemical OpCo LP [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of Production Facilities \| production_facility			3
Limited Partner [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of units sold in public offering \| shares			12,937,500
Limited Partner [Member] \| Westlake [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Partnership's ownership interest (percent)			5.80%
Predecessor [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest							$ 0

Description Of Business And Significant Accounting Policies (Schedule Of Estimated Useful Lives Of Assets) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Capitalized interest	$ 5,961,000	$ 5,116,000	$ 2,638,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ 353,323,000	$ 354,133,000	$ 0
Buildings And Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	25 years
Plant And Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	25 years
Ethylene Pipeline [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	35 years
Minimum [Member] \| Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	3 years
Maximum [Member] \| Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	10 years
Westlake [Member] \| Affiliated Entity [Member]
Property, Plant and Equipment [Line Items]
Capitalized interest	$ 5,961,000

Initial Public Offering and Purchase of Additional Interests (Details)				5 Months Ended	12 Months Ended
	Apr. 29, 2015 USD ($)	Apr. 01, 2015	Aug. 04, 2014 USD ($) lease lb $ / shares $ / lb shares	Dec. 31, 2014 USD ($)	Dec. 31, 2016 USD ($) lb $ / lb shares	Dec. 31, 2015 USD ($) shares	Aug. 05, 2014 USD ($)
Limited Partners' Capital Account [Line Items]
Net proceeds from issuance of common units					$ 0	$ 0
Payments of unit issuance costs			$ 24,412,000
Westlake Chemical OpCo LP [Member] \| Loans Payable [Member] \| 2013 Promissory Note [Member]
Limited Partners' Capital Account [Line Items]
Debt assumed by acquiree							$ 167,116,000
Westlake Chemical OpCo LP [Member] \| IPO [Member]
Limited Partners' Capital Account [Line Items]
Net proceeds from issuance of common units			286,088,000
Westlake Chemical OpCo LP [Member] \| IPO [Member] \| Preformation Capital Expenditure [Member]
Limited Partners' Capital Account [Line Items]
Use of proceeds from public offering			151,729,000
Westlake Chemical OpCo LP [Member] \| IPO [Member] \| Cash Reserve Turnaround [Member]
Limited Partners' Capital Account [Line Items]
Use of proceeds from public offering			55,419,000
Westlake Chemical OpCo LP [Member] \| IPO [Member] \| Intercompany Debt [Member]
Limited Partners' Capital Account [Line Items]
Use of proceeds from public offering			$ 78,940,000
Westlake [Member]
Limited Partners' Capital Account [Line Items]
Excess cash paid over carrying value of partnership interest				$ 242,572,000
Common units [Member] \| Westlake [Member]
Limited Partners' Capital Account [Line Items]
Units outstanding \| shares			1,436,115
Subordinated units [Member] \| Westlake [Member]
Limited Partners' Capital Account [Line Items]
Units outstanding \| shares			12,686,115
Westlake [Member]
Limited Partners' Capital Account [Line Items]
Number of units sold in public offering \| shares			12,937,500
Price per unit (usd per unit) \| $ / shares			$ 24.00
Price per unit, net of underwriting discount (usd per unit) \| $ / shares			$ 22.53
Westlake [Member] \| Over-Allotment Option [Member]
Limited Partners' Capital Account [Line Items]
Number of units sold in public offering \| shares			1,687,500
Westlake [Member] \| Westlake [Member]
Limited Partners' Capital Account [Line Items]
Partnership's ownership interest (percent)			5.80%
Westlake Chemical OpCo LP [Member] \| Affiliated Entity [Member]
Limited Partners' Capital Account [Line Items]
Partnership's ownership interest (percent)		13.30%	10.60%
Additional ownership interest acquired	2.70%	2.70%	4.80%
Amount paid to purchase additional limited partner interest	$ 135,341,000
Carrying value of additional partnership interest purchased			$ 43,516,000
Westlake Chemical OpCo LP [Member] \| Ethylene Sales Agreement [Member]
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Exchange agreement amount of purchase agreement \| lb					200,000,000
Purchase commitment, fixed margin on variable pricing \| $ / lb					0.006
Westlake Chemical OpCo LP [Member] \| Ethylene Sales Agreement [Member] \| Investee [Member]
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Minimum percentage required to be purchased					95.00%
Westlake Chemical OpCo LP [Member] \| Westlake [Member] \| Majority-Owned Subsidiary, Unconsolidated [Member]
Limited Partners' Capital Account [Line Items]
Partnership's ownership interest (percent)		86.70%
Westlake Chemical OpCo LP [Member] \| Westlake [Member] \| Ethylene Sales Agreement [Member] \| Investee [Member]
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Term of sales agreement			12 years
Minimum percentage required to be purchased			95.00%
Maximum mass required to be purchased \| lb			3,800,000,000
Number of years used to calculate average expenses			5 years
Purchase commitment, fixed margin on variable pricing \| $ / lb			0.10
Purchase commitment, renewal term			12 months
Westlake Chemical OpCo LP [Member] \| Westlake [Member] \| Excess Production Option [Member] \| Investee [Member]
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Percentage of excess production that can be purchased			95.00%
Purchase commitment, fixed margin on variable pricing \| $ / lb			0.10
Westlake Chemical OpCo LP [Member] \| Westlake [Member] \| Feedstock Supply Agreement [Member] \| Investee [Member]
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Related party transactions, term of agreements			12 months
Westlake Chemical OpCo LP [Member] \| Westlake [Member] \| Services And Secondment Agreement [Member] \| Investee [Member]
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Related party transactions, term of agreements			12 years
Period of default in performance that can allow a party to terminate agreement			30 days
Westlake Chemical OpCo LP [Member] \| Westlake [Member] \| Site Lease Agreement [Member] \| Investee [Member]
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Number of lease agreements \| lease			2
Operating lease, rental amount			$ 1
Term of operating lease			50 years
Westlake [Member] \| MLP Revolver [Member]
Long-term Commitment (Excluding Unconditional Purchase Obligation) [Abstract]
Maximum borrowing capacity	$ 300,000,000
Westlake [Member] \| Common units [Member]
Limited Partners' Capital Account [Line Items]
Units outstanding \| shares					1,436,115	143,611
Westlake [Member] \| Subordinated units [Member]
Limited Partners' Capital Account [Line Items]
Units outstanding \| shares					12,686,115	12,686,115

Accounts Receivable—Third Parties (Schedule Of Accounts Receivable) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts Receivable, Net [Abstract]
Trade customers	$ 11,913	$ 12,097
Allowance for doubtful accounts	(564)	(170)
Trade Customer Receivable Net Current	11,349	11,927
Other Receivables, Net, Current	736	0
Accounts receivable, net—third parties	12,085	11,927
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning balance	170	0	$ 2,105
Charged to Expense	394	170	65
Deductions	0	0	(2,170)
Ending balance	$ 564	$ 170	$ 0

Inventories (Schedule Of Inventory) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Inventory, Net [Abstract]
Finished products	$ 3,610	$ 3,527
Feedstock, additives, and chemicals	324	352
Inventories	$ 3,934	$ 3,879

Property, Plant And Equipment (Schedule Of Property, Plant And Equipment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment, Net [Abstract]
Building and improvements	$ 16,757	$ 16,124
Plant and equipment	1,690,317	1,231,684
Other	72,215	67,353
Property, plant and equipment, gross	1,779,289	1,315,161
Less: Accumulated depreciation	(644,070)	(601,980)
Property, plant and equipment, net, before construction in progress	1,135,219	713,181
Construction in progress	87,019	307,288
Property, plant and equipment, net	1,222,238	1,020,469
Depreciation expense	$ 77,444	$ 64,369	$ 60,004

Other Assets (Schedule Of Intangible and Other Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Schedule of Finite-Lived And Indefinite-Lived Intangible Assets [Line Items]
Goodwill, Cost	$ 5,814	$ 5,814
Goodwill, Net	5,814	5,814
Interest Rate Contract, Gross	290	436
Other Assets [Line Items]
Interest rate contract	290	436
Turnaround costs, Cost	154,453	100,020
Turnaround costs, Accumulated Amortization	(65,268)	(67,767)
Turnaround costs, Net	89,185	32,253
Other, Costs	8,723	8,710
Other, Accumulated Amortization	(3,187)	(2,620)
Other, Net	5,536	6,090
Total deferred charges and other assets, Cost	163,466	109,166
Total deferred charges and other assets, Accumulated Amortization	(68,455)	(70,387)
Total deferred charges and other assets, Net	95,011	38,779
Other assets, Cost	169,280	114,980
Other assets, Accumulated Amortization	(68,455)	(70,387)
Total other assets, net	$ 100,825	$ 44,593
Deferred Turnaround Costs [Member]
Other Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	6 years
Other Amortizable Assets [Member]
Other Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	17 years

Other Assets (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
Other Assets (Narrative) (Details) - USD ($) $ in Thousands	Oct. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Discounted cash flow projections period	9 years
Rate used to discount future cash flows for goodwill impairment test	8.80%
Percentage future cash flows of segment could decrease by and not be impaired		10.00%
Other Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization		$ 20,766	$ 16,841	$ 17,607

Long-Term Debt (Schedule of Long-term Debt) (Details) - USD ($) $ in Thousands				12 Months Ended
	Apr. 29, 2015	Apr. 01, 2015	Aug. 04, 2014	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Long-term debt				$ 594,629	$ 384,006
Weighted average interest rate on all long-term debt					3.30%
Predecessor [Member]
Related Party Transaction [Line Items]
Long-term debt					$ 384,006
Limited Partner [Member] \| Senior Notes [Member] \| 2013 Promissory Note [Member]
Related Party Transaction [Line Items]
Long-term debt				$ 31,775	$ 31,775
Limited Partner [Member] \| Senior Notes [Member] \| 2013 Promissory Note [Member] \| Prime Rate [Member]
Related Party Transaction [Line Items]
Basis spread on variable rate, percent				1.50%	1.50%
Limited Partner [Member] \| Senior Notes [Member] \| 2013 Promissory Note [Member] \| Predecessor [Member]
Related Party Transaction [Line Items]
Long-term debt					$ 31,775
Limited Partner [Member] \| Senior Unsecured Revolving Credit Facility [Member] \| OpCo Revolver [Member]
Related Party Transaction [Line Items]
Long-term debt				$ 427,513	$ 216,890
Limited Partner [Member] \| Senior Unsecured Revolving Credit Facility [Member] \| OpCo Revolver [Member] \| LIBOR [Member]
Related Party Transaction [Line Items]
Basis spread on variable rate, percent				3.00%	3.00%
Limited Partner [Member] \| Senior Unsecured Revolving Credit Facility [Member] \| OpCo Revolver [Member] \| Predecessor [Member]
Related Party Transaction [Line Items]
Long-term debt					$ 216,890
Limited Partner [Member] \| Senior Unsecured Revolving Credit Facility [Member] \| MLP Revolver [Member]
Related Party Transaction [Line Items]
Long-term debt				$ 135,341	$ 135,341
Minimum [Member] \| Limited Partner [Member] \| Line of Credit [Member] \| MLP Revolver [Member] \| LIBOR [Member]
Related Party Transaction [Line Items]
Basis spread on variable rate, percent				2.00%	2.00%
Weslake [Member] \| MLP Revolver [Member]
Related Party Transaction [Line Items]
Maximum borrowing capacity	$ 300,000
Weslake [Member] \| Limited Partner [Member] \| OpCo Revolver [Member] \| Westlake Chemical OpCo LP [Member]
Related Party Transaction [Line Items]
Maximum borrowing capacity			$ 600,000
Weslake [Member] \| Limited Partner [Member] \| Line of Credit [Member] \| OpCo Revolver [Member] \| Westlake Chemical OpCo LP [Member] \| LIBOR [Member]
Related Party Transaction [Line Items]
Basis spread on variable rate, percent				3.00%
Weslake [Member] \| Limited Partner [Member] \| Line of Credit [Member] \| MLP Revolver [Member]
Related Party Transaction [Line Items]
Maximum consolidated leverage ratio during one year following acquisitions	5.50
Leverage capital ratio required during other periods	4.50
Weslake [Member] \| Affiliated Entity [Member]
Related Party Transaction [Line Items]
Long-term debt				$ 594,629	$ 384,006
Weslake [Member] \| Minimum [Member] \| Limited Partner [Member] \| Line of Credit [Member] \| MLP Revolver [Member] \| LIBOR [Member]
Related Party Transaction [Line Items]
Basis spread on variable rate, percent	2.00%
Weslake [Member] \| Maximum [Member] \| Limited Partner [Member] \| Line of Credit [Member] \| MLP Revolver [Member] \| LIBOR [Member]
Related Party Transaction [Line Items]
Basis spread on variable rate, percent	3.00%
Westlake Chemical OpCo LP [Member] \| Affiliated Entity [Member]
Related Party Transaction [Line Items]
Additional ownership interest	2.70%	2.70%	4.80%
Amount paid to purchase additional limited partner interest	$ 135,341

Distributions and Net Income Per Limited Partner Unit (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Jan. 27, 2017	Dec. 31, 2016
Westlake Chemical OpCo LP [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Distribution declared per unit (usd per share)	$ 0.3450
Cash Distribution [Member] \| IDR Holders [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Incentive distribution	$ 142
Common units [Member] \| Cash Distribution [Member]
Subsequent Event [Line Items]
Minimum Quarterly Distribution Per Unit		$ 0.2750
Subordinated units [Member] \| Cash Distribution [Member]
Subsequent Event [Line Items]
Minimum Quarterly Distribution Per Unit		0.2750
Common and Subordinated units [Member] \| Cash Distribution [Member]
Subsequent Event [Line Items]
Minimum quarterly distribution per unit (usd per share)		$ 0.3163

Distributions and Net Income Per Limited Partner Unit (Incentive Distribution Rights) (Details)	12 Months Ended
	Dec. 31, 2016 $ / shares
Above $0.3163 up to $0.3438 [Member] \| Unit Holders [Member]
Distribution Made to Limited Partner [Line Items]
Marginal Percentage Interest in Distributions	85.00%
Above $0.3163 up to $0.3438 [Member] \| IDR Holders [Member]
Distribution Made to Limited Partner [Line Items]
Marginal Percentage Interest in Distributions	15.00%
Above $0.3438 up to $0.4125 [Member] \| Unit Holders [Member]
Distribution Made to Limited Partner [Line Items]
Marginal Percentage Interest in Distributions	75.00%
Above $0.3438 up to $0.4125 [Member] \| IDR Holders [Member]
Distribution Made to Limited Partner [Line Items]
Marginal Percentage Interest in Distributions	25.00%
Above $0.4125 [Member] \| Unit Holders [Member]
Distribution Made to Limited Partner [Line Items]
Marginal Percentage Interest in Distributions	50.00%
Above $0.4125 [Member] \| IDR Holders [Member]
Distribution Made to Limited Partner [Line Items]
Marginal Percentage Interest in Distributions	50.00%
Minimum [Member] \| Above $0.3163 up to $0.3438 [Member]
Distribution Made to Limited Partner [Line Items]
Quarterly distribution per unit threshold (usd per share)	$ 0.3163
Minimum [Member] \| Above $0.3438 up to $0.4125 [Member]
Distribution Made to Limited Partner [Line Items]
Quarterly distribution per unit threshold (usd per share)	0.3438
Minimum [Member] \| Above $0.4125 [Member]
Distribution Made to Limited Partner [Line Items]
Quarterly distribution per unit threshold (usd per share)	0.4125
Maximum [Member] \| Above $0.3163 up to $0.3438 [Member]
Distribution Made to Limited Partner [Line Items]
Quarterly distribution per unit threshold (usd per share)	0.3438
Maximum [Member] \| Above $0.3438 up to $0.4125 [Member]
Distribution Made to Limited Partner [Line Items]
Quarterly distribution per unit threshold (usd per share)	$ 0.4125

Distributions and Net Income Per Limited Partner Unit (Income In Excess Of Distribution) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								5 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Distribution declared										$ 36,081	$ 31,966	$ 12,052
Net income subsequent to the IPO in excess of distribution										4,859	7,865	1,525
Limited partners' interest in net income subsequent to IPO	$ 10,851	$ 8,661	$ 9,344	$ 12,084	$ 10,785	$ 10,103	$ 10,443	$ 8,500	$ 13,577	$ 40,940	$ 39,831	13,577
Distributions per common unit (usd per unit)									$ 0.45	$ 1.29	$ 1.15
Common units [Member]
Distribution declared										$ 19,016	$ 16,980	6,403
Net income subsequent to the IPO in excess of distribution										2,581	4,178	810
Limited partners' interest in net income subsequent to IPO										21,597	21,158	7,213
Subordinated units [Member]
Distribution declared										16,784	14,986	5,649
Net income subsequent to the IPO in excess of distribution										2,278	3,687	715
Limited partners' interest in net income subsequent to IPO										19,062	18,673	6,364
IDR Holders [Member]
Distributions declared with respect to the incentive distribution rights										281	0	0
Net income subsequent to the IPO in excess of distribution										0	0	0
Limited partners' interest in net income subsequent to IPO										281	0	0
Cash Distribution [Member] \| IDR Holders [Member]
Distributions declared with respect to the incentive distribution rights										$ 281	$ 0	$ 0

Distributions and Net Income Per Limited Partner Unit (Basic and Diluted Income Per Limited Partner Unit) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								5 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Limited Partners' Capital Account [Line Items]
Distribution										$ 36,081	$ 31,966	$ 12,052
Net income in excess of distribution										4,859	7,865	1,525
Limited partners' interest in net income subsequent to IPO	$ 10,851	$ 8,661	$ 9,344	$ 12,084	$ 10,785	$ 10,103	$ 10,443	$ 8,500	$ 13,577	$ 40,940	$ 39,831	$ 13,577
Weighted average units outsanding:
Basic and diluted (units)										27,059,730	27,059,730	27,059,730
IDR Holders [Member]
Limited Partners' Capital Account [Line Items]
Distributions declared with respect to the incentive distribution rights										$ 281	$ 0	$ 0
Net income in excess of distribution										0	0	0
Limited partners' interest in net income subsequent to IPO										281	0	0
IDR Holders [Member] \| Cash Distribution [Member]
Limited Partners' Capital Account [Line Items]
Distributions declared with respect to the incentive distribution rights										281	0	0
Limited Partners' Common Units [Member]
Limited Partners' Capital Account [Line Items]
Distribution										19,016	16,980	6,403
Net income in excess of distribution										2,581	4,178	810
Limited partners' interest in net income subsequent to IPO										$ 21,597	$ 21,158	$ 7,213
Weighted average units outsanding:
Basic and diluted (units)										14,373,615	14,373,615	14,373,615
Net income per limited partner unit:
Income per limited partner unit (usd per unit)	$ 0.39	$ 0.32	$ 0.34	$ 0.45	$ 0.40	$ 0.37	$ 0.39	$ 0.31	$ 0.50	$ 1.50	$ 1.47	$ 0.50
Limited Partners' Subordinated Units [Member]
Limited Partners' Capital Account [Line Items]
Distribution										$ 16,784	$ 14,986	$ 5,649
Net income in excess of distribution										2,278	3,687	715
Limited partners' interest in net income subsequent to IPO										$ 19,062	$ 18,673	$ 6,364
Weighted average units outsanding:
Basic and diluted (units)										12,686,115	12,686,115	12,686,115
Net income per limited partner unit:
Income per limited partner unit (usd per unit)	$ 0.39	$ 0.32	$ 0.34	$ 0.45	$ 0.40	$ 0.37	$ 0.39	$ 0.31	$ 0.50	$ 1.50	$ 1.47	$ 0.50

Related Party Transactions (Sales to Related Parties) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Net sales - Westlake	$ 853,719	$ 834,918
Predecessor [Member]
Related Party Transaction [Line Items]
Net sales - Westlake			$ 1,292,089
Affiliated Entity [Member] \| Westlake [Member]
Related Party Transaction [Line Items]
Net sales - Westlake	$ 853,719	$ 834,918
Affiliated Entity [Member] \| Westlake [Member] \| Predecessor [Member]
Related Party Transaction [Line Items]
Net sales - Westlake			$ 1,292,089

Related Party Transactions (Cost of Sales from Related Parties) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Cost of sales	$ 595,405	$ 624,339
Predecessor [Member]
Related Party Transaction [Line Items]
Cost of sales			$ 1,003,888
Affiliated Entity [Member] \| Westlake [Member]
Related Party Transaction [Line Items]
Feedstock purchased from Westlake and included in cost of sales	287,778	307,582
Other charges from Westlake and included in cost of sales	85,872	74,050
Cost of sales	$ 373,650	$ 381,632
Affiliated Entity [Member] \| Westlake [Member] \| Predecessor [Member]
Related Party Transaction [Line Items]
Feedstock purchased from Westlake and included in cost of sales			155,232
Other charges from Westlake and included in cost of sales			60,264
Cost of sales			$ 215,496

Related Party Transactions (Services from Related Parties Included in SG&A Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Services received from Westlake and included in selling, general and administrative expenses	$ 24,887	$ 23,550
Predecessor [Member]
Related Party Transaction [Line Items]
Services received from Westlake and included in selling, general and administrative expenses			$ 29,256
Affiliated Entity [Member] \| Westlake [Member]
Related Party Transaction [Line Items]
Services received from Westlake and included in selling, general and administrative expenses	$ 21,971	$ 20,681
Affiliated Entity [Member] \| Westlake [Member] \| Predecessor [Member]
Related Party Transaction [Line Items]
Services received from Westlake and included in selling, general and administrative expenses			$ 21,302

Related Party Transactions (Goods and Services from Related Parties that have been Capitalized) (Details) - Affiliated Entity [Member] - Westlake [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Goods and services purchased from Westlake and capitalized as assets	$ 17,874	$ 4,332
Predecessor [Member]
Related Party Transaction [Line Items]
Goods and services purchased from Westlake and capitalized as assets			$ 5,823

Related Party Transactions (Accounts Receivable from and Accounts Payable to Related Parties) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Accounts receivable, net—Westlake	$ 126,977	$ 39,655
Accounts payable—Westlake	12,130	$ 15,550
Affiliated Entity [Member] \| Westlake [Member]
Related Party Transaction [Line Items]
Accounts receivable, net—Westlake	126,977
Accounts payable—Westlake	$ 12,130
Ethylene Sales Agreement [Member] \| Investee [Member] \| Westlake Chemical OpCo LP [Member]
Related Party Transaction [Line Items]
Minimum percentage required to be purchased	95.00%
Deficiency amount	$ 13,106

Related Party Transactions (Debt Payable to Related Parties) (Details) - USD ($) $ in Thousands	5 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Interest on related party debt payable		$ 12,607	$ 4,967
Interest capitalized		5,961	5,116	$ 2,638
Accrued interest on related party debt		5,517	2,879
Long-term debt payable to Westlake		594,629	384,006
Predecessor [Member]
Related Party Transaction [Line Items]
Interest on related party debt payable				$ 10,499
Long-term debt payable to Westlake			384,006
Affiliated Entity [Member] \| Westlake [Member]
Related Party Transaction [Line Items]
Interest capitalized		5,961
Long-term debt payable to Westlake		594,629	384,006
Accrued Liabilities [Member] \| Affiliated Entity [Member] \| Westlake [Member]
Related Party Transaction [Line Items]
Accrued interest on related party debt		5,517	2,879
Other Nonoperating Income (Expense) [Member] \| Affiliated Entity [Member] \| Westlake [Member]
Related Party Transaction [Line Items]
Interest on related party debt payable	$ 10,499	$ 12,607	$ 4,967

Related Party Transactions (General) (Details)		5 Months Ended	12 Months Ended
Related Party Transactions (General) (Details)	Aug. 04, 2014 USD ($) lease	Dec. 31, 2014 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Related Party Transaction [Line Items]
Income Taxes Paid			$ 633,000	$ 1,264,000	$ 0
Westlake [Member] \| Senior Notes [Member]
Related Party Transaction [Line Items]
Outstanding debt				754,000,000
Unamortized discount				774,000
Westlake [Member] \| Revolving Credit Facility [Member]
Related Party Transaction [Line Items]
Outstanding letters of credit				30,098,000
Affiliated Entity [Member] \| Reimbursement to Parent for State Tax [Member] \| Westlake [Member]
Related Party Transaction [Line Items]
Income Taxes Paid		$ 0	$ 245,000	$ 1,033,000
Investee [Member] \| Westlake [Member] \| Site Lease Agreement [Member] \| Westlake Chemical OpCo LP [Member]
Related Party Transaction [Line Items]
Number of lease agreements \| lease	2
Term of operating lease	50 years
Operating lease, rental amount	$ 1

Partners' Equity (Incentive Distribution Rights) (Details)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Percentage of minimum quarterly distribution partnership must pay to end subordination period	150.00%

Accumulated Other Comprehensive Income (Details) - Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	$ 280	$ 0
Interest rate contract - Other comprehensive income before reclassifications	(416)	85
Interest rate contract - Amounts reclassified to net income	336	195
Balance at end of period	$ 200	$ 280

Unit-Based Compensation (Details) $ / shares in Units, $ in Thousands	5 Months Ended	12 Months Ended
	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) director $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Jul. 15, 2014 shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition		1 year 11 months 16 days
Phantom Share Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Beginning balance		16,963	4,404
Granted		9,900	12,559
Vested		(5,543)
Ending balance	4,404	21,320	16,963
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted Average Fair Value, beginning balance (usd per share) \| $ / shares		$ 22.89	$ 29.49
Weighted Average Grant Date Fair Value, Granted (usd per share) \| $ / shares		22.91	20.57
Weighted Average Grant Date Fair Value, Vested (usd per share) \| $ / shares		23.38
Weighted Average Fair Value, ending balance (usd per share) \| $ / shares	$ 29.49	$ 22.77	$ 22.89
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value \| $		$ 123,221
Westlake Chemical Partners LP Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Number of units authorized				1,270,000
Total units available for grant		1,248,680
Unrecognized compensation cost \| $		$ 300,296
Westlake Chemical Partners LP Long-Term Incentive Plan [Member] \| Selling, General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Total compensation cost \| $	$ 15	$ 194	$ 75
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Deferred Compensation Arrangement with Individual, Number of Directors That Retired in Period \| director		1

Derivative Instruments (Narrative) (Details)	12 Months Ended
Derivative Instruments (Narrative) (Details)	Dec. 31, 2016 USD ($) derivative	Dec. 31, 2015 USD ($) derivative	Dec. 31, 2014 USD ($)
Derivative [Line Items]
Number of contracts	0	0
Ineffective portion of a derivative instrument \| $	$ 0	$ 0
Derivatives Not Designated As Hedging Instrument [Member]
Derivative [Line Items]
Number of contracts	0	0
Fair Value Hedging [Member] \| Designated as Fair Value Hedges [Member]
Derivative [Line Items]
Number of contracts	0	0
Predecessor [Member]
Derivative [Line Items]
Ineffective portion of a derivative instrument \| $			$ 0

Derivative Instruments (Fair Values Of Derivative Instruments In Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Cash Flow Hedging [Member] \| Other Assets [Member] \| Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Fair Value, Net	$ 290	$ 436

Derivative Instruments (Impact Of Derivative Instruments Designated As Fair Value Hedges) (Details) - Cash Flow Hedging [Member] - Interest Rate Contract [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Loss Recognized in Other Comprehensive Income (Loss), Effective Portion	$ (416)	$ 85
Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion	$ (336)	$ (195)

Derivative Instruments (Impact Of Derivative Instruments Not Designated As Fair Value Hedges) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2014 USD ($)
Commodity forward contracts [Member] \| Derivatives Not Designated As Hedging Instrument [Member] \| Cost of Sales [Member] \| Predecessor [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivative	$ (9,244)

Fair Value Measurements (Schedule Of Assets And Liabilities On A Recurring Basis) (Details) - Fair Value, Measurements, Recurring [Member] - Interest Rate Contract [Member] - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Derivative Assets, at Fair Value	$ 290	$ 436
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Derivative Assets, at Fair Value	$ 290	$ 436

Fair Value Measurements (Schedule Of Carrying And Fair Values Of Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 594,629	$ 384,006
2013 Promissory Note [Member] \| Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	31,775	31,775
OpCo Revolver [Member] \| Senior Unsecured Revolving Credit Facility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	442,716	215,738
MLP Revolver [Member] \| Senior Unsecured Revolving Credit Facility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	134,835	130,439
Limited Partner [Member] \| 2013 Promissory Note [Member] \| Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	31,775	31,775
Limited Partner [Member] \| OpCo Revolver [Member] \| Senior Unsecured Revolving Credit Facility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	427,513	216,890
Limited Partner [Member] \| MLP Revolver [Member] \| Senior Unsecured Revolving Credit Facility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 135,341	$ 135,341

Income Taxes (Schedule Of The Provision For (Benefit From) Income Taxes) (Details) - USD ($) $ in Thousands	5 Months Ended	7 Months Ended	12 Months Ended
	Dec. 31, 2014	Aug. 03, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Entity Information [Line Items]
Federal	$ 0		$ 0	$ 0
State and local	800		691	1,128
Total Current	800		691	1,128
Federal	0		0	0
State and local	265		344	(456)
Total deferred	265		344	(456)
Total provision	$ 1,065		$ 1,035	$ 672
Predecessor [Member]
Entity Information [Line Items]
Federal		$ 168,773
State and local		21,207
Total Current		189,980
Federal		6,890
State and local		1,453
Total deferred		8,343			$ 8,608
Total provision		$ 198,323			$ 199,388

Income Taxes (Reconciliation Of Taxes Computed At The Statutory Rate To Income Tax Expense) (Details) - USD ($) $ in Thousands	5 Months Ended	7 Months Ended	12 Months Ended
	Dec. 31, 2014	Aug. 03, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Entity Information [Line Items]
Provision for federal income tax, at statutory rate	$ 52,343		$ 124,054	$ 124,083
State income tax provision, net of federal income tax effect	1,065		1,035	672
Partnership income not subject to entity-level tax	(52,343)		(124,054)	(124,083)
Manufacturing deduction	0		0	0
Other, net	0		0	0
Total provision	$ 1,065		$ 1,035	$ 672
Predecessor [Member]
Entity Information [Line Items]
Provision for federal income tax, at statutory rate		$ 195,880
State income tax provision, net of federal income tax effect		14,729
Partnership income not subject to entity-level tax		0
Manufacturing deduction		(12,214)
Other, net		(72)
Total provision		$ 198,323			$ 199,388

Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	5 Months Ended	7 Months Ended	12 Months Ended
	Dec. 31, 2014	Aug. 03, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Entity Information [Line Items]
Federal	$ 0		$ 0	$ 0
Property, plant and equipment			(1,488)	(1,291)
Turnaround costs			(248)	(101)
Deferred tax liabilities-total			(1,736)	(1,392)
Balance sheet classifications
Noncurrent deferred tax liability			(1,736)	(1,392)
State and local	800		691	1,128
Current Income Tax Expense (Benefit)	800		691	1,128
Federal	0		0	0
State and local	265		344	(456)
Deferred Income Tax Expense (Benefit)	265		344	(456)
Total provision	$ 1,065		$ 1,035	$ 672
Predecessor [Member]
Entity Information [Line Items]
Federal		$ 168,773
Balance sheet classifications
State and local		21,207
Current Income Tax Expense (Benefit)		189,980
Federal		6,890
State and local		1,453
Deferred Income Tax Expense (Benefit)		8,343			$ 8,608
Total provision		$ 198,323			$ 199,388

Supplemental Information (Accrued Liabilities and Other Income, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accrued Liabilities
Accrued liabilities	$ 15,717	$ 23,407
Accrued interest	5,517	2,879
Accrual related to capital expenditures	2,647	14,745
Accrued maintenance expense	$ 2,586	$ 2,949

Supplemental Information (Cash Flow Information) (Details) - USD ($)	5 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Reduction in capital expenditure accrual		$ 18,113,000	$ (14,552,000)	$ (418,000)
Interest Paid, Net		9,901,000	9,538,000	1,366,000
Income Taxes Paid		633,000	1,264,000	0
Westlake [Member] \| Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party notes payable deemed settled through net investment				238,600,000
Cash transferred in related party notes payable settlement			0
Predecessor [Member] \| Westlake [Member] \| Affiliated Entity [Member]
Related Party Transaction [Line Items]
Interest incurred, added to principal on promissory notes outstanding				$ 9,315,000
State and Local Jurisdiction [Member]
Related Party Transaction [Line Items]
Income Taxes Paid		388,000	231,000
Reimbursement to Parent for State Tax [Member] \| Westlake [Member] \| Affiliated Entity [Member]
Related Party Transaction [Line Items]
Income Taxes Paid	$ 0	$ 245,000	$ 1,033,000

Commitments And Contingencies (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) settlement	Apr. 21, 2014 USD ($)
Settled Litigation [Member]
Loss Contingencies [Line Items]
Number of claims settled \| settlement	2
Amount of settlements	$ 192
Unfavorable Regulatory Action [Member] \| Pending Litigation [Member]
Loss Contingencies [Line Items]
Estimate of possible loss		$ 100

Commitments And Contingencies (Future Minimum Lease Commitments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
2017	$ 1,144
2018	907
2019	839
2020	771
2021	656
Thereafter	383
Total future minimum lease commitments	4,700
Approximate rental expense	$ 2,542	$ 3,125	$ 3,558

Major Customer and Concentration Risk (Details)	12 Months Ended
Major Customer and Concentration Risk (Details)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net sales [Member] \| Customer Concentration Risk [Member] \| Westlake [Member] \| Affiliated Entity [Member]
Concentration Risk [Line Items]
Concentration risk percentage	86.50%	82.90%	73.80%

Subsequent Events (Details) - Subsequent Event [Member] $ / shares in Units, $ in Thousands	Jan. 27, 2017 USD ($) $ / shares
Westlake Chemical OpCo LP [Member]
Subsequent Event [Line Items]
Distribution declared per unit (usd per share) \| $ / shares	$ 0.3450
Cash Distribution [Member] \| IDR Holders [Member]
Subsequent Event [Line Items]
Incentive distribution \| $	$ 142

Quarterly Financial Information (Unaudited) (Summary Of Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								5 Months Ended	7 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Aug. 03, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net sales	$ 293,937	$ 229,354	$ 210,841	$ 252,604	$ 248,506	$ 248,619	$ 251,705	$ 258,391			$ 986,736	$ 1,007,221
Gross profit	105,735	86,801	88,381	110,414	97,982	94,145	94,528	96,227			391,331	382,882
Income from operations	98,581	81,013	82,533	104,317	92,258	88,314	88,533	90,227			366,444	359,332
Net income	93,581	75,859	81,192	102,771	91,175	87,046	87,243	88,389	$ 148,486	$ 361,334	353,403	353,853
Net income attributable to Westlake Chemical Partners LP	$ 10,851	$ 8,661	$ 9,344	$ 12,084	$ 10,785	$ 10,103	$ 10,443	$ 8,500	$ 13,577		40,940	39,831	$ 13,577
Common units [Member]
Net income attributable to Westlake Chemical Partners LP											$ 21,597	$ 21,158	$ 7,213
Basic and diluted earnings per common unit holder (usd per unit)	$ 0.39	$ 0.32	$ 0.34	$ 0.45	$ 0.40	$ 0.37	$ 0.39	$ 0.31	$ 0.50		$ 1.50	$ 1.47	$ 0.50
Subordinated units [Member]
Net income attributable to Westlake Chemical Partners LP											$ 19,062	$ 18,673	$ 6,364
Basic and diluted earnings per common unit holder (usd per unit)	$ 0.39	$ 0.32	$ 0.34	$ 0.45	$ 0.40	$ 0.37	$ 0.39	$ 0.31	$ 0.50		$ 1.50	$ 1.47	$ 0.50
Predecessor [Member]
Net sales													$ 1,749,700
Gross profit													745,812
Income from operations													716,556
Net income										$ 361,334	$ 0	$ 0	$ 509,820