Guarantor Disclosures (Condensed Consolidating Financial Information Statement Of Operations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010		Sep. 30, 2010		Jun. 30, 2010		Mar. 31, 2010		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 859,175	$ 968,372	$ 925,049	$ 867,252	$ 795,387		$ 779,677		$ 818,389		$ 778,334		$ 3,619,848	[1]	$ 3,171,787	[1]	$ 2,325,723	[1]
Cost of sales													3,060,842		2,689,104		2,130,595
Gross profit	77,260	147,067	167,095	167,584	164,124		134,855		126,024		57,680		559,006		482,683		195,128
Selling, general and administrative expenses													112,210		104,319		87,871
Income from operations	50,459	117,331	138,369	140,637	137,052		107,346		99,537		34,429		446,796		378,364		107,257
Interest expense													(50,992)		(39,875)		(34,957)
Other income, (expense), net													5,628		4,471		6,453
Income before income taxes													401,432		342,960		78,753
(Benefit from) provision for income taxes													142,466		121,567		25,758
Equity in net income of subsidiaries
Net income	26,443	67,930	81,049	83,544	84,073	[2]	62,731	[2]	56,942	[2]	17,647	[2]	258,966		221,393		52,995
Westlake Chemical Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales
Cost of sales
Gross profit
Selling, general and administrative expenses													3,762		4,257		4,185
Income from operations													(3,762)		(4,257)		(4,185)
Interest expense													(50,919)		(39,829)		(34,864)
Other income, (expense), net													10,217		15,045		14,843
Income before income taxes													(44,464)		(29,041)		(24,206)
(Benefit from) provision for income taxes													(11,835)		(2,471)		(6,314)
Equity in net income of subsidiaries													291,595		247,963		70,887
Net income													258,966		221,393		52,995
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales													3,581,470		3,130,513		2,289,953
Cost of sales													3,024,419		2,653,234		2,099,795
Gross profit													557,051		477,279		190,158
Selling, general and administrative expenses													102,989		95,441		80,213
Income from operations													454,062		381,838		109,945
Interest expense													(73)		(46)		(93)
Other income, (expense), net													(4,212)		(12,715)		(12,981)
Income before income taxes													449,777		369,077		96,871
(Benefit from) provision for income taxes													155,313		122,541		31,620
Equity in net income of subsidiaries
Net income													294,464		246,536		65,251
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales													42,202		44,006		38,980
Cost of sales													40,247		38,602		34,010
Gross profit													1,955		5,404		4,970
Selling, general and administrative expenses													5,459		4,621		3,473
Income from operations													(3,504)		783		1,497
Interest expense
Other income, (expense), net													(377)		2,141		4,591
Income before income taxes													(3,881)		2,924		6,088
(Benefit from) provision for income taxes													(1,012)		1,497		452
Equity in net income of subsidiaries
Net income													(2,869)		1,427		5,636
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales													(3,824)		(2,732)		(3,210)
Cost of sales													(3,824)		(2,732)		(3,210)
Gross profit
Selling, general and administrative expenses
Income from operations
Interest expense
Other income, (expense), net
Income before income taxes
(Benefit from) provision for income taxes
Equity in net income of subsidiaries													(291,595)		(247,963)		(70,887)
Net income													$ (291,595)		$ (247,963)		$ (70,887)

[1] Revenues are attributed to countries based on location of customer.

[2] Basic and diluted earnings per common share ("EPS") for each quarter is computed using the weighted average shares outstanding during that quarter, while EPS for the year is computed using the weighted average shares outstanding for the year. As a result, the sum of the EPS for each of the four quarters may not equal the EPS for the year.