Guarantor Disclosures (Condensed Consolidating Financial Information Balance Sheet) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 825,901	$ 630,299	$ 245,592	$ 90,239
Accounts receivable, net	407,372	362,863
Inventories	490,777	450,028
Prepaid expenses and other current assets	12,495	15,482
Deferred income taxes	19,611	17,288
Total current assets	1,756,156	1,475,960
Property, plant and equipment, net	1,232,066	1,170,334
Equity investments	46,741	46,314
Restricted cash	96,283	150,288
Other assets, net	135,575	111,248
Total assets	3,266,821	2,954,144
Accounts payable	227,034	204,774
Accrued liabilities	137,561	118,804
Total current liabilities	364,595	323,578
Long-term debt	764,563	764,482
Deferred income taxes	330,791	315,518
Other liabilities	50,560	45,496
Stockholders' equity	1,756,312	1,505,070	1,284,982	1,239,060
Total liabilities and stockholders' equity	3,266,821	2,954,144
Westlake Chemical Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	803,320	611,158	232,802	88,368
Accounts receivable, net		128,628
Inventories
Prepaid expenses and other current assets	363	162
Deferred income taxes	430	357
Total current assets	804,113	740,305
Property, plant and equipment, net
Equity investments	2,597,598	2,320,094
Restricted cash	96,283	150,288
Other assets, net	17,650	16,897
Total assets	3,515,644	3,227,584
Accounts payable	1,005,529	952,000
Accrued liabilities	76	16,868
Total current liabilities	1,005,605	968,868
Long-term debt	753,674	753,593
Deferred income taxes
Other liabilities	53	53
Stockholders' equity	1,756,312	1,505,070
Total liabilities and stockholders' equity	3,515,644	3,227,584
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	2,517	53	77	69
Accounts receivable, net	1,384,705	1,302,314
Inventories	478,229	437,130
Prepaid expenses and other current assets	10,332	13,763
Deferred income taxes	19,049	16,771
Total current assets	1,894,832	1,770,031
Property, plant and equipment, net	1,223,073	1,159,051
Equity investments	53,912	53,274
Restricted cash
Other assets, net	132,968	108,352
Total assets	3,304,785	3,090,708
Accounts payable	210,476	189,852
Accrued liabilities	120,656	228,364
Total current liabilities	331,132	418,216
Long-term debt	10,889	10,889
Deferred income taxes	336,165	320,813
Other liabilities	50,458	45,435
Stockholders' equity	2,576,141	2,295,355
Total liabilities and stockholders' equity	3,304,785	3,090,708
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	20,064	19,088	12,713	1,802
Accounts receivable, net	949	2,086
Inventories	12,548	12,898
Prepaid expenses and other current assets	1,800	1,557
Deferred income taxes	132	160
Total current assets	35,493	35,789
Property, plant and equipment, net	8,993	11,283
Equity investments	35,650	35,588
Restricted cash
Other assets, net	2,467	3,769
Total assets	82,603	86,429
Accounts payable	3,748	4,541
Accrued liabilities	2,392	2,121
Total current liabilities	6,140	6,662
Long-term debt	11,500	11,500
Deferred income taxes	636	972
Other liabilities	49	8
Stockholders' equity	64,278	67,287
Total liabilities and stockholders' equity	82,603	86,429
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents
Accounts receivable, net	(978,282)	(1,070,165)
Inventories
Prepaid expenses and other current assets
Deferred income taxes
Total current assets	(978,282)	(1,070,165)
Property, plant and equipment, net
Equity investments	(2,640,419)	(2,362,642)
Restricted cash
Other assets, net	(17,510)	(17,770)
Total assets	(3,636,211)	(3,450,577)
Accounts payable	(992,719)	(941,619)
Accrued liabilities	14,437	(128,549)
Total current liabilities	(978,282)	(1,070,168)
Long-term debt	(11,500)	(11,500)
Deferred income taxes	(6,010)	(6,267)
Other liabilities
Stockholders' equity	(2,640,419)	(2,362,642)
Total liabilities and stockholders' equity	$ (3,636,211)	$ (3,450,577)