Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Net sales	$ 1,086,061	$ 1,185,002	$ 2,061,248	$ 2,288,533
Cost of sales	844,695	831,821	1,564,297	1,650,806
Gross profit	241,366	353,181	496,951	637,727
Selling, general and administrative expenses	61,428	57,807	114,737	113,073
Income from operations	179,938	295,374	382,214	524,654
Other income (expense)
Interest expense	(5,915)	(8,958)	(12,600)	(18,549)
Other income, net	8,181	22,058	10,826	31,154
Income before income taxes	182,204	308,474	380,440	537,259
Provision for income taxes	66,584	98,413	135,884	176,791
Net income	115,620	210,061	244,556	360,468
Net income attributable to noncontrolling interests	4,496	4,966	10,304	9,031
Net income attributable to Westlake Chemical Corporation	$ 111,124	$ 205,095	$ 234,252	$ 351,437
Earnings per common share attributable to Westlake Chemical Corporation
Basic (usd per share)	$ 0.85	$ 1.55	$ 1.80	$ 2.65
Diluted (usd per share)	$ 0.85	$ 1.54	$ 1.79	$ 2.64
Weighted average shares outstanding:
Basic	129,583,224	132,538,123	129,886,594	132,625,857
Diluted	129,980,527	133,044,975	130,290,521	133,124,697
Dividends per common share	$ 0.1815	$ 0.1650	$ 0.3630	$ 0.3300