Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 144,710	$ 128,936
Pension and other post-retirement benefits liability
Amortization of benefits liability	572	334
Income tax provision on pension and other post-retirement benefits liability	(171)	(128)
Foreign currency translation	19,126	22,805
Income tax provision on foreign currency translation	(1,782)	0
Net unrealized holding gains (losses) on investments
Unrealized holding gains on investments	0	24,428
Reclassification of net realized gains to net income	0	(52)
Income tax provision on available-for-sale investments	0	(8,758)
Other	(75)	0
Other comprehensive income, net of income taxes	17,670	38,629
Comprehensive income	162,380	167,565
Comprehensive income attributable to noncontrolling interests, net of tax of $813 and $0 for March 31, 2017 and 2016, respectively.	6,520	5,808
Comprehensive income attributable to Westlake Chemical Corporation	$ 155,860	$ 161,757