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