Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 170,156	$ 170,290	$ 497,631	$ 439,453
Pension and other post-retirement reserves adjustment (excluding amortization)	31	489	62	978
Pension and other post-retirement benefits liability
Amortization of benefits liability	240	695	685	2,004
Income tax provision on pension and other post-retirement benefits liability	(81)	(78)	(240)	(394)
Foreign currency translation adjustments	(37,792)	546	(37,882)	(844)
Available-for-sale investments
Unrealized holding gains on investments	2,129	205	6,960	205
Reclassification of net realized gains to net income	0	0	1,212	0
Income tax provision on available-for-sale investments	(766)	(74)	(2,066)	(74)
Other comprehensive (loss) income	(36,301)	805	(33,817)	(81)
Comprehensive income	133,855	171,095	463,814	439,372
Comprehensive income attributable to noncontrolling interests, net of tax	2,399	0	2,399	0
Comprehensive income attributable to Westlake Chemical Corporation	$ 131,456	$ 171,095	$ 461,415	$ 439,372