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Description Of Business And Significant Accounting Policies (Narrative) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Aug. 04, 2014
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Undistributed earnings included in retained earnings	$ 5,619
Capitalized interest	7,059us-gaap_InterestCostsCapitalized	25,932us-gaap_InterestCostsCapitalized	7,706us-gaap_InterestCostsCapitalized
Goodwill	$ 62,016us-gaap_Goodwill	$ 62,016us-gaap_Goodwill	$ 29,990us-gaap_Goodwill
Amortization period, minimum (in years)	3 years
Amortization period, maximum (in years)	6 years
Other assets amortization period, minimum (in years)	2 years
Other assets amortization period, maximum (in years)	20 years
Subsidiaries [Member] \| Limited Partner [Member] \| IPO [Member] \| Westlake Chemical Partners LP [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of units sold in public offering				12,937,500
Limited partner interest				10.60%
Westlake Chemical OpCo LP [Member] \| Limited Partner [Member] \| IPO [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Limited partner interest				89.40%
Westlake Chemical OpCo LP [Member] \| Subsidiaries [Member] \| Louisiana
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of production facilities	2
Westlake Chemical OpCo LP [Member] \| Subsidiaries [Member] \| Kentucky
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of production facilities	1
Westlake Chemical OpCo LP [Member] \| Subsidiaries [Member] \| Limited Partner [Member] \| IPO [Member] \| Subsidiary of Common Parent [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Limited partner interest				10.60%