Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Net sales	$ 1,279,028	$ 1,188,037	$ 3,340,276	$ 3,476,570
Cost of sales	1,076,895	876,761	2,641,192	2,527,567
Gross profit	202,133	311,276	699,084	949,003
Selling, general and administrative expenses	72,729	57,248	179,757	170,321
Transaction and integration-related costs	82,841	0	90,550	0
Income from operations	46,563	254,028	428,777	778,682
Other income (expense)
Interest expense	(24,366)	(8,211)	(36,966)	(26,760)
Other income, net	41,265	2,636	52,091	33,790
Income before income taxes	63,462	248,453	443,902	785,712
(Benefit from) provision for income taxes	(6,552)	60,033	129,332	236,824
Net income	70,014	188,420	314,570	548,888
Net income attributable to noncontrolling interests	4,352	4,816	14,656	13,847
Net income attributable to Westlake Chemical Corporation	$ 65,662	$ 183,604	$ 299,914	$ 535,041
Earnings per common share attributable to Westlake Chemical Corporation:
Basic (usd per share)	$ 0.51	$ 1.39	$ 2.31	$ 4.04
Diluted (usd per share)	$ 0.51	$ 1.39	$ 2.29	$ 4.02
Weighted average common shares outstanding:
Basic (in shares)	128,793,661	131,664,296	129,519,577	132,301,814
Diluted (in shares)	129,379,956	132,121,235	130,103,897	132,786,534
Dividends per common share (usd per share)	$ 0.1906	$ 0.1815	$ 0.5536	$ 0.5115