Guarantor Disclosures (Condensed Consolidating Financial Information Balance Sheet) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 461,301	$ 790,078	$ 825,901	$ 630,299
Marketable securities	239,388	124,873
Accounts receivable, net	428,457	400,159
Inventories	471,879	399,298
Prepaid expenses and other current assets	13,888	14,700
Deferred income taxes	34,169	22,305
Total current assets	1,649,082	1,751,413
Property, plant and equipment, net	2,088,014	1,510,048
Equity investments	66,875	43,736
Other assets, net	256,938	106,999
Total assets	4,060,909	3,412,196
Accounts payable, current	249,613	217,050
Accrued liabilities	155,245	181,460
Total current liabilities	404,858	398,510
Long-term debt	763,879	763,761
Deferred income taxes	437,976	326,290
Other liabilities	35,593	51,379
Stockholders' equity	2,418,603	1,872,256	1,756,312	1,505,070
Total liabilities and stockholders' equity	4,060,909	3,412,196
Westlake Chemical Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	420,948	753,881	803,320	611,158
Marketable securities	239,388	124,873
Accounts receivable, net	3,879	7,933
Inventories	0	0
Prepaid expenses and other current assets	778	389
Deferred income taxes	441	431
Total current assets	665,434	887,507
Property, plant and equipment, net	0	0
Equity investments	2,815,752	3,018,926
Other assets, net	15,393	17,033
Total assets	3,496,579	3,923,466
Accounts payable, current	316,652	1,285,530
Accrued liabilities	8,334	12,808
Total current liabilities	324,986	1,298,338
Long-term debt	752,990	752,872
Deferred income taxes	0	0
Other liabilities	0	0
Stockholders' equity	2,418,603	1,872,256
Total liabilities and stockholders' equity	3,496,579	3,923,466
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	6,227	6,973	2,517	53
Marketable securities	0	0
Accounts receivable, net	738,156	1,675,274
Inventories	456,306	385,140
Prepaid expenses and other current assets	11,312	11,386
Deferred income taxes	33,422	21,581
Total current assets	1,245,423	2,100,354
Property, plant and equipment, net	2,081,091	1,502,902
Equity investments	100,326	65,448
Other assets, net	246,125	94,678
Total assets	3,672,965	3,763,382
Accounts payable, current	223,134	192,443
Accrued liabilities	161,140	178,915
Total current liabilities	384,274	371,358
Long-term debt	10,889	10,889
Deferred income taxes	443,026	331,320
Other liabilities	35,533	51,312
Stockholders' equity	2,799,243	2,998,503
Total liabilities and stockholders' equity	3,672,965	3,763,382
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	34,126	29,224	20,064	19,088
Marketable securities	0	0
Accounts receivable, net	2,755	2,959
Inventories	15,573	14,158
Prepaid expenses and other current assets	1,798	2,925
Deferred income taxes	306	293
Total current assets	54,558	49,559
Property, plant and equipment, net	6,923	7,146
Equity investments	31,518	32,923
Other assets, net	1,199	1,252
Total assets	94,198	90,880
Accounts payable, current	10,649	13,969
Accrued liabilities	1,282	852
Total current liabilities	11,931	14,821
Long-term debt	0	0
Deferred income taxes	729	934
Other liabilities	60	67
Stockholders' equity	81,478	75,058
Total liabilities and stockholders' equity	94,198	90,880
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	0	0	0	0
Marketable securities	0	0
Accounts receivable, net	(316,333)	(1,286,007)
Inventories	0	0
Prepaid expenses and other current assets	0	0
Deferred income taxes	0	0
Total current assets	(316,333)	(1,286,007)
Property, plant and equipment, net	0	0
Equity investments	(2,880,721)	(3,073,561)
Other assets, net	(5,779)	(5,964)
Total assets	(3,202,833)	(4,365,532)
Accounts payable, current	(300,822)	(1,274,892)
Accrued liabilities	(15,511)	(11,115)
Total current liabilities	(316,333)	(1,286,007)
Long-term debt	0	0
Deferred income taxes	(5,779)	(5,964)
Other liabilities	0	0
Stockholders' equity	(2,880,721)	(3,073,561)
Total liabilities and stockholders' equity	$ (3,202,833)	$ (4,365,532)