Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net sales—Westlake	$ 257,040	$ 235,031
Total net sales	299,086	284,272
Cost of sales	208,432	191,767
Gross profit	90,654	92,505
Selling, general and administrative expenses	6,973	7,133
Income from operations	83,681	85,372
Other income (expense)
Interest expense—Westlake	(5,900)	(4,866)
Other income, net	815	491
Income before income taxes	78,596	80,997
Income tax provision	200	283
Net income	78,396	80,714
Less: Net income attributable to noncontrolling interest in OpCo	63,441	68,419
Net income attributable to Westlake Chemical Partners LP	$ 14,955	$ 12,295
Weighted average limited partner units outstanding (basic and diluted)
Weighted average limited partner units outstanding (basic and diluted) (in shares)	32,345,398	32,236,449
Common units [Member]
Other income (expense)
Net income attributable to Westlake Chemical Partners LP	$ 14,955	$ 11,562
Net income per limited partner unit attributable to Westlake Chemical Partners LP (basic and diluted)
Income per limited partner unit (usd per share)	$ 0.46	$ 0.36
Weighted average limited partner units outstanding (basic and diluted)
Weighted average limited partner units outstanding (basic and diluted) (in shares)	32,345,398	32,236,449
Common units [Member] | Publicly and Privately Held [Member]
Weighted average limited partner units outstanding (basic and diluted)
Weighted average limited partner units outstanding (basic and diluted) (in shares)	18,223,168	18,115,036
Common units [Member] | Westlake [Member]
Weighted average limited partner units outstanding (basic and diluted)
Weighted average limited partner units outstanding (basic and diluted) (in shares)	14,122,230	14,122,230
Product and Service, Other [Member]
Total net sales	$ 42,046	$ 49,241