Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Weighted Average Number of Limited Partnership and General Partnership Unit Outstanding, Basic and Diluted	35,194,545	35,188,189	35,194,545	34,251,005
Net sales—Westlake	$ 217,763	$ 216,678	$ 660,022	$ 703,765
Total net sales	231,969	249,925	721,018	819,073
Cost of sales	131,578	156,706	427,049	543,242
Gross profit	100,391	93,219	293,969	275,831
Selling, general and administrative expenses	6,255	6,822	18,590	21,434
Income from operations	94,136	86,397	275,379	254,397
Other income (expense)
Interest expense—Westlake	(2,320)	(4,411)	(9,701)	(15,436)
Other income, net	17	565	725	2,533
Income before income taxes	91,833	82,551	266,403	241,494
Income tax provision (benefit)	(15)	72	408	509
Net income	91,848	82,479	265,995	240,985
Less: Net income attributable to noncontrolling interest in OpCo	73,313	67,557	214,853	197,375
Net income attributable to Westlake Chemical Partners LP and limited partners' interest in net income	$ 18,535	$ 14,922	$ 51,142	$ 43,610
Common units [Member]
Weighted Average Number of Limited Partnership and General Partnership Unit Outstanding, Basic and Diluted	35,194,545	35,188,189	35,194,545	34,251,005
Other income (expense)
Net income attributable to Westlake Chemical Partners LP and limited partners' interest in net income	$ 18,535	$ 14,922	$ 51,142	$ 43,610
Net Income (Loss), Per Outstanding Limited Partnership Unit, Basic, Net of Tax	$ 0.53	$ 0.42	$ 1.45	$ 1.27
Common units [Member] | Publicly and Privately Held [Member]
Weighted Average Number of Limited Partnership and General Partnership Unit Outstanding, Basic and Diluted	21,072,315	21,065,959	21,072,315	20,128,775
Common units [Member] | Westlake [Member]
Weighted Average Number of Limited Partnership and General Partnership Unit Outstanding, Basic and Diluted	14,122,230	14,122,230	14,122,230	14,122,230
Net co-product, ethylene and other sales—third parties
Total net sales	$ 14,206	$ 33,247	$ 60,996	$ 115,308