Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
Net sales	$ 1,185,002	$ 998,576	$ 2,288,533	$ 2,026,252
Cost of sales	831,821	692,605	1,650,806	1,433,271
Gross profit	353,181	305,971	637,727	592,981
Selling, general and administrative expenses	57,807	39,183	113,073	78,138
Income from operations	295,374	266,788	524,654	514,843
Other income (expense)
Interest expense	(8,958)	(9,539)	(18,549)	(18,696)
Other income, net	22,058	4,601	31,154	7,110
Income before income taxes	308,474	261,850	537,259	503,257
Provision for income taxes	98,413	92,407	176,791	175,782
Net income	210,061	169,443	360,468	327,475
Net income attributable to noncontrolling interests	4,966	0	9,031	0
Net income attributable to Westlake Chemical Corporation	$ 205,095	$ 169,443	$ 351,437	$ 327,475
Earnings per common share attributable to Westlake Chemical Corporation
Basic (usd per share)	$ 1.55	$ 1.27	$ 2.65	$ 2.45
Diluted (usd per share)	$ 1.54	$ 1.26	$ 2.64	$ 2.44
Weighted average shares outstanding:
Basic	132,538,123	133,223,705	132,625,857	133,148,398
Diluted	133,044,975	133,767,890	133,124,697	133,690,836
Dividends per common share	$ 0.1650	$ 0.1260	$ 0.3300	$ 0.2520