Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 685,016us-gaap_ProfitLoss	$ 610,425us-gaap_ProfitLoss	$ 385,555us-gaap_ProfitLoss
Pension and other post-retirement benefits liability
Pension and other post-retirement reserves adjustment (excluding amortization)	(25,766)	12,969	(4,301)
Amortization of benefits liability	924	2,712	2,340
Income tax (provision) benefit on pension and other post-retirement benefits liability	8,096	(6,026)	753
Foreign currency translation adjustments	(60,128)	(1,607)	623
Available-for-sale investments
Unrealized holding gains on investments	1,301	256	14,582
Reclassification of net realized loss (gains) to net income	(1,212)	19	(16,429)
Income tax (provision) benefit on available-for-sale investment	32	99	(662)
Other comprehensive (loss) income	(76,817)	8,224	(1,770)
Comprehensive income	608,199	618,649	383,785
Comprehensive income attributable to noncontrolling interests, net of tax	6,493	0	0
Comprehensive income attributable to Westlake Chemical Corporation	$ 601,706us-gaap_ComprehensiveIncomeNetOfTax	$ 618,649us-gaap_ComprehensiveIncomeNetOfTax	$ 383,785us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amortization of benefits liability included in other comprehensive income, before tax.

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