Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Income Statement [Abstract]
Net sales	$ 1,253,227		$ 1,004,165		$ 3,279,479		$ 2,807,859
Cost of sales	891,707		699,694		2,324,978		2,002,092
Gross profit	361,520		304,471		954,501		805,767
Selling, general and administrative expenses	54,759		37,869		132,897		109,883
Income from operations	306,761		266,602		821,604		695,884
Other income (expense)
Interest expense	(9,486)		(3,297)		(28,182)		(14,921)
Other (expense) income, net	(2,670)		(287)		4,440		3,137
Income before income taxes	294,605		263,018		797,862		684,100
Provision for income taxes	124,449		92,728		300,231		244,647
Net income	170,156		170,290		497,631		439,453
Net income attributable to noncontrolling interests	2,399		0		2,399		0
Net income to Westlake Chemical Corporation	$ 167,757		$ 170,290		$ 495,232		$ 439,453
Earnings per share:
Basic	$ 1.26	[1]	$ 1.28	[1]	$ 3.71	[1]	$ 3.29	[1]
Diluted	$ 1.25	[1]	$ 1.27	[1]	$ 3.69	[1]	$ 3.27	[1]
Weighted average shares outstanding:
Basic	133,299,458	[1]	133,257,494	[1]	133,199,304	[1]	133,256,054	[1]
Diluted	133,846,059	[1]	133,811,108	[1]	133,743,145	[1]	133,806,758	[1]
Dividends per common share	$ 0.1650		$ 0.1125		$ 0.4170		$ 0.3000

[1] Share amounts and per share data for the three and nine months ended September 30, 2013 have been restated to reflect the effect of a two-for-one stock split on March 18, 2014. See Note 1 for additional information.