Westlake (WLK) 10-Q 7 Nov 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 31, 2014
Document Documentand Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'WLK	'
Entity Registrant Name	'WESTLAKE CHEMICAL CORP	'
Entity Central Index Key	'0001262823	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	133,082,630

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets	'	'
Cash and cash equivalents	$813,468	$461,301
Marketable Securities, Current	0	239,388
Accounts receivable, net	592,964	428,457
Inventories	500,552	471,879
Prepaid expenses and other current assets	18,884	13,888
Deferred income taxes	26,080	34,169
Total current assets	1,951,948	1,649,082
Property, plant and equipment, net	2,710,475	2,088,014
Equity investments	70,828	66,875
Other assets, net	'	'
Intangible assets, net	222,728	159,046
Deferred charges and other assets	170,304	97,892
Total other assets, net	393,032	256,938
Total assets	5,126,283	4,060,909
Current liabilities	'	'
Accounts payable	263,365	249,613
Accrued liabilities	309,671	155,245
Total current liabilities	573,036	404,858
Long-term debt	763,968	763,879
Deferred income taxes	513,773	437,976
Other liabilities	153,158	35,593
Total liabilities	2,003,935	1,642,306
Commitments and contingencies (Notes 7 and 15)	'	'
Stockholders' equity	'	'
Preferred stock, $0.01 par value, 50,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.01 par value, 300,000,000 shares authorized; 134,680,164 and 134,580,208 shares issued at September 30, 2014 and December 31, 2013, respectively (Note 1)	1,347	1,346
Common stock, held in treasury, at cost; 1,220,544 and 1,252,922 shares at September 30, 2014 and December 31, 2013, respectively (Note 1)	-53,248	-46,220
Additional paid-in capital	527,992	511,432
Retained earnings	2,394,203	1,954,661
Accumulated other comprehensive loss	-36,433	-2,616
Total Westlake Chemical Corporation stockholders' equity	2,833,861	2,418,603
Noncontrolling interests	288,487	0
Total equity	3,122,348	2,418,603
Total liabilities and equity	$5,126,283	$4,060,909

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]	'	'
Preferred stock, par value	$0.01	$0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	300,000,000	150,000,000
Common stock, shares issued	134,680,164	134,580,208
Common stock, held in treasury	1,220,544	1,252,922

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended				9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Income Statement [Abstract]	'		'		'		'
Net sales	$1,253,227		$1,004,165		$3,279,479		$2,807,859
Cost of sales	891,707		699,694		2,324,978		2,002,092
Gross profit	361,520		304,471		954,501		805,767
Selling, general and administrative expenses	54,759		37,869		132,897		109,883
Income from operations	306,761		266,602		821,604		695,884
Other income (expense)	'		'		'		'
Interest expense	-9,486		-3,297		-28,182		-14,921
Other (expense) income, net	-2,670		-287		4,440		3,137
Income before income taxes	294,605		263,018		797,862		684,100
Provision for income taxes	124,449		92,728		300,231		244,647
Net income	170,156		170,290		497,631		439,453
Net income attributable to noncontrolling interests	2,399		0		2,399		0
Net income to Westlake Chemical Corporation	$167,757		$170,290		$495,232		$439,453
Earnings per share:	'		'		'		'
Basic	$1.26	[1]	$1.28	[1]	$3.71	[1]	$3.29	[1]
Diluted	$1.25	[1]	$1.27	[1]	$3.69	[1]	$3.27	[1]
Weighted average shares outstanding:	'		'		'		'
Basic	133,299,458	[1]	133,257,494	[1]	133,199,304	[1]	133,256,054	[1]
Diluted	133,846,059	[1]	133,811,108	[1]	133,743,145	[1]	133,806,758	[1]
Dividends per common share	$0.17		$0.11		$0.42		$0.30
[1]	Share amounts and per share data for the three and nine months ended September 30, 2013 have been restated to reflect the effect of a two-for-one stock split on MarchB 18, 2014. See Note 1 for additional information.

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]	'	'	'	'
Net income	$170,156	$170,290	$497,631	$439,453
Pension and other post-retirement reserves adjustment (excluding amortization)	31	489	62	978
Pension and other post-retirement benefits liability	'	'	'	'
Amortization of benefits liability	240	695	685	2,004
Income tax provision on pension and other post-retirement benefits liability	-81	-78	-240	-394
Foreign currency translation adjustments	-37,792	546	-37,882	-844
Available-for-sale investments	'	'	'	'
Unrealized holding gains on investments	2,129	205	6,960	205
Reclassification of net realized gains to net income	0	0	1,212	0
Income tax provision on available-for-sale investments	-766	-74	-2,066	-74
Other comprehensive (loss) income	-36,301	805	-33,817	-81
Comprehensive income	133,855	171,095	463,814	439,372
Comprehensive income attributable to noncontrolling interests, net of tax	2,399	0	2,399	0
Comprehensive income attributable to Westlake Chemical Corporation	$131,456	$171,095	$461,415	$439,372

Consolidated_Statements_of_Cha

Consolidated Statements of Changes in Stockholders' Equity Statement (USD $)	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Benefits Liability Net Of Tax [Member]	Cumulative Foreign Currency Exchange [Member]	Unrealized Holding Losses On Investments Net Of Tax [Member]	Noncontrolling Interest [Member]
In Thousands, except Share data
Amount, beginning balance at Dec. 31, 2012	$1,872,256	$1,345	($13,302)	$495,581	$1,399,472	($16,351)	$5,511	$0	$0
Number of Shares, beginning balance at Dec. 31, 2012	'	134,374,448	568,986	'	'	'	'	'	'
Net income	610,425	'	'	'	610,425	'	'	'	0
Other comprehensive (loss) income	8,224	'	'	'	'	9,655	-1,607	176	0
Common stock repurchased, shares	'	'	683,936	'	'	'	'	'	'
Common stock repurchased	-32,918	'	-32,918	'	'	'	'	'	0
Shares issued - stock- based compensation, shares	3,437	1	'	3,436	'	'	'	'	'
Shares issued - stock- based compensation	'	225,924	'	'	'	'	'	'	'
Stock-based compensation, net of tax on stock options exercised, shares	'	-20,164	'	'	'	'	'	'	'
Stock-based compensation, net of tax on stock options exercised	12,415	'	'	12,415	'	'	'	'	'
Dividends paid	-55,236	'	'	'	-55,236	'	'	'	'
Amount, ending balance at Dec. 31, 2013	2,418,603	1,346	-46,220	511,432	1,954,661	-6,696	3,904	176	0
Number of Shares, ending balance at Dec. 31, 2013	'	134,580,208	1,252,922	'	'	'	'	'	'
Net income	497,631	'	'	'	495,232	'	'	'	2,399
Net income	495,232	'	'	'	'	'	'	'	'
Other comprehensive (loss) income	-33,817	'	'	'	'	383	-37,882	3,682	0
Common stock repurchased, shares	'	'	104,163	'	'	'	'	'	'
Common stock repurchased	-9,495	'	-9,495	'	'	'	'	'	0
Shares issued - stock- based compensation, shares	5,502	1	2,467	3,034	'	'	'	'	'
Shares issued - stock- based compensation	'	124,566	-136,541	'	'	'	'	'	'
Stock-based compensation, net of tax on stock options exercised, shares	'	-24,610	'	'	'	'	'	'	'
Stock-based compensation, net of tax on stock options exercised	13,526	'	'	13,526	'	'	'	'	'
Dividends paid	-55,690	'	'	'	-55,690	'	'	'	'
Issuance of Westlake Chemical Partners LP common units	286,088	'	'	'	'	'	'	'	286,088
Amount, ending balance at Sep. 30, 2014	$3,122,348	$1,347	($53,248)	$527,992	$2,394,203	($6,313)	($33,978)	$3,858	$288,487
Number of Shares, ending balance at Sep. 30, 2014	'	134,680,164	1,220,544	'	'	'	'	'	'

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities	'	'
Net income	$497,631	$439,453
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation and amortization	148,394	116,294
Provision for doubtful accounts	295	3,600
Amortization of debt issuance costs	1,172	1,093
Stock-based compensation expense	6,856	4,804
Loss from disposition of fixed assets	2,635	4,679
Deferred income taxes	34,459	83,443
Windfall tax benefits from share-based payment arrangements	-6,670	-5,056
(Income) loss from equity method investments, net of dividends	-3,199	1,586
Other gains, net	-495	0
Changes in operating assets and liabilities	'	'
Accounts receivable	6,055	-18,874
Inventories	80,492	-26,325
Prepaid expenses and other current assets	458	-5,038
Accounts payable	-98,769	19,518
Accrued liabilities	111,965	-15,755
Other, net	-5,155	-55,922
Net cash provided by operating activities	776,124	547,500
Cash flows from investing activities	'	'
Acquisition of business, net of cash acquired	-611,087	-178,309
Additions to equity investments	0	-23,338
Additions to property, plant and equipment	-311,183	-498,290
Construction of assets pending sale-leaseback	0	-136
Proceeds from disposition of assets	145	78
Proceeds from repayment of loan acquired	45,923	0
Proceeds from repayment of loan to affiliate	0	167
Proceeds from sale and maturities of securities	342,045	239,764
Purchase of securities and other investments	-117,332	-232,286
Settlements of derivative instruments	-689	-2,297
Net cash used for investing activities	-652,178	-694,647
Cash flows from financing activities	'	'
Capitalized debt issuance costs	-1,167	'
Dividends paid	-55,690	-40,204
Net proceeds from issuance of Westlake Chemical Partners LP common units	286,088	0
Proceeds from exercise of stock options	5,502	3,182
Repurchase of common stock for treasury	-9,495	-19,409
Windfall tax benefits from share-based payment arrangements	6,670	5,056
Net cash provided by financing activities	231,908	-51,375
Effect of exchange rate changes on cash	-3,687	0
Net increase in cash and cash equivalents	352,167	-198,522
Cash and cash equivalents at beginning of period	461,301	790,078
Cash and cash equivalents at end of period	$813,468	$591,556

Basis_of_Financial_Statements

Basis of Financial Statements	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of Financial Statements	'
	Basis of Financial Statements
	The accompanying unaudited consolidated interim financial statements were prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the "SEC") for interim periods. Accordingly, certain information and footnotes required for complete financial statements under generally accepted accounting principles in the United States ("U.S. GAAP") have not been included. These interim consolidated financial statements should be read in conjunction with the December 31, 2013 financial statements and notes thereto of Westlake Chemical Corporation (the "Company") included in the annual report on Form 10-K for the fiscal year ended December 31, 2013 (the "2013 Form 10-K"), filed with the SEC on February 21, 2014. These financial statements have been prepared in conformity with the accounting principles and practices as disclosed in the notes to the consolidated financial statements of the Company for the fiscal year ended December 31, 2013.
	In the opinion of the Company's management, the accompanying unaudited consolidated interim financial statements reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair statement of the Company's financial position as of September 30, 2014, its results of operations for the three and nine months ended September 30, 2014 and 2013 and the changes in its cash position for the nine months ended September 30, 2014 and 2013.
	Results of operations and changes in cash position for the interim periods presented are not necessarily indicative of the results that will be realized for the fiscal year ending December 31, 2014 or any other interim period. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.
	On February 14, 2014, the Company's Board of Directors authorized a two-for-one split of the Company's common stock. Stockholders of record as of February 28, 2014 were entitled to one additional share for every share outstanding, which was distributed on March 18, 2014. The total number of authorized common stock shares and associated par value were unchanged by this stock split. All share amounts and per share data included in the accompanying consolidated financial statements and related notes have been restated to reflect the effect of the stock split.
	In March 2014, the Company formed Westlake Chemical Partners LP ("WLKP") to operate, acquire and develop ethylene production facilities and related assets. On August 4, 2014, WLKP closed its initial public offering of 12,937,500 common units. See Note 19 for additional information. The Company consolidates WLKP and records a noncontrolling interest for the interest in WLKP not owned by the Company.
	Recent Accounting Pronouncements
	Revenue from Contracts with Customers
	In May 2014, the Financial Accounting Standards Board ("FASB") issued an accounting standards update on a comprehensive new revenue recognition standard that will supersede the existing revenue recognition guidance. The new accounting guidance creates a framework by which an entity will allocate the transaction price to separate performance obligations and recognize revenue when each performance obligation is satisfied. Under the new standard, entities will be required to use judgment and make estimates, including identifying performance obligations in a contract, estimating the amount of variable consideration to include in the transaction price, allocating the transaction price to each separate performance obligation and determining when an entity satisfies its performance obligations. The standard allows for either "full retrospective" adoption, meaning that the standard is applied to all of the periods presented with a cumulative catch-up as of the earliest period presented, or "modified retrospective" adoption, meaning the standard is applied only to the most current period presented in the financial statements with a cumulative catch-up as of the current period. The accounting standard will be effective for reporting periods beginning after December 15, 2016. The Company is in the process of evaluating the impact that the new accounting guidance will have on its consolidated financial position, results of operations and cash flows.
	Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern
	In August 2014, the FASB issued an accounting standards update on management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern. The new accounting guidance requires management to perform interim and annual assessments of an entity's ability to continue as a going concern within one year of the date the financial statements are issued. An entity must provide certain disclosures if "conditions or events raise substantial doubt about the entity's ability to continue as a going concern." The accounting standard will be effective for reporting periods ending after December 15, 2016 and is not expected to have an impact on the Company's consolidated financial position, results of operations and cash flows.

Financial_Instruments

Financial Instruments	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Financial Instruments	'
	Financial Instruments
	Cash Equivalents
	The Company had $747,008 and $263,967 of held-to-maturity securities with original maturities of three months or less, primarily consisting of corporate debt securities, classified as cash equivalents at September 30, 2014 and December 31, 2013, respectively. The Company's investments in held-to-maturity securities are held at amortized cost, which approximates fair value.
	Available-for-Sale Marketable Securities
	Investments in available-for-sale securities were classified as follows:
		September 30,				December 31,
		2014				2013
	Current	$	—			$	239,388
	Non-current	21,066				—
	Total available-for-sale securities	$	21,066			$	239,388
	The cost, gross unrealized gains, gross unrealized losses and fair value of the Company’s available-for-sale securities were as follows:
			September 30, 2014
			Cost				Gross		Gross			Fair Value
							Unrealized		Unrealized
							Gains		Losses
	Equity securities		$	15,044			$	6,022	$	—		$	21,066
	Total available-for-sale securities		$	15,044			$	6,022	$	—		$	21,066
			December 31, 2013
			Cost				Gross		Gross			Fair Value
							Unrealized		Unrealized
							Gains		Losses (1)
	Debt securities
	Corporate bonds		$	108,300			$	340	$	(69	)	$	108,571
	U.S. government debt (2)		106,335				60		(79		)	106,316
	Asset-backed securities		24,478				34		(11		)	24,501
	Total available-for-sale securities		$	239,113			$	434	$	(159	)	$	239,388
	_____________
	-1	All unrealized loss positions were held at a loss for less than 12 months.
	-2	U.S. Treasury obligations, U.S. government agency obligations and U.S government agency mortgage-backed securities.
	As of September 30, 2014 and December 31, 2013, net unrealized gains on the Company's available-for-sale securities of $3,858 and $176, respectively, net of income tax expense of $2,164 and $99, respectively, were recorded in accumulated other comprehensive income. See Note 10 for the fair value hierarchy of the Company’s available-for-sale securities.
	The proceeds from sales and maturities of available-for-sale securities and the gross realized gains and losses included in the consolidated statement of operations are reflected in the table below. The cost of securities sold was determined using the specific identification method. There were no sales or maturities of available-for-sale securities during the three and nine months ended September 30, 2013.
			Nine Months Ended September 30,
			2014
	Proceeds from sales and maturities of securities		$	342,045
	Gross realized gains		$	1,311
	Gross realized losses		$	(99	)

Accounts_Receivable

Accounts Receivable	9 Months Ended
	Sep. 30, 2014
Accounts Receivable, Net [Abstract]	'
Accounts Receivable	'
	Accounts Receivable
	Accounts receivable consist of the following:
		September 30,			December 31,
		2014			2013
	Trade customers	$	576,735		$	410,302
	Affiliates	631			315
	Allowance for doubtful accounts	(13,772		)	(11,741		)
		563,594			398,876
	Federal and state taxes	5,374			20,820
	Other	23,996			8,761
	Accounts receivable, net	$	592,964		$	428,457

Inventories

Inventories	9 Months Ended
	Sep. 30, 2014
Inventory Disclosure [Abstract]	'
Inventories	'
	Inventories
	Inventories consist of the following:
		September 30,		December 31,
		2014		2013
	Finished products	$	268,969	$	232,658
	Feedstock, additives and chemicals	166,268		180,646
	Materials and supplies	65,315		58,575
	Inventories	$	500,552	$	471,879

Property_Plant_and_Equipment

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment	'
	Property, Plant and Equipment
	As of September 30, 2014, the Company had property, plant and equipment, net totaling $2,710,475. The Company assesses these assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable, including when negative conditions such as significant current or projected operating losses exist. Other factors considered by the Company when determining if an impairment assessment is necessary include, but are not limited to, significant changes or projected changes in supply and demand fundamentals (which would have a negative impact on operating rates or margins), new technological developments, new competitors with significant raw material or other cost advantages, adverse changes associated with the U.S. and world economies and uncertainties associated with governmental actions. Long-lived assets assessed for impairment are grouped at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities.
	Depreciation expense on property, plant and equipment of $45,080 and $32,460 is included in cost of sales in the consolidated statements of operations for the three months ended September 30, 2014 and 2013, respectively. Depreciation expense on property, plant and equipment of $123,000 and $95,995 is included in cost of sales in the consolidated statements of operations for the nine months ended September 30, 2014 and 2013, respectively.

Other_Assets

Other Assets	9 Months Ended
	Sep. 30, 2014
Other Assets [Abstract]	'
Other Assets	'
	Other Assets
	Amortization expense on intangible and other assets of $9,283 and $8,634 is included in the consolidated statements of operations for the three months ended September 30, 2014 and 2013, respectively. Amortization expense on intangible and other assets of $26,566 and $21,392 is included in the consolidated statements of operations for the nine months ended September 30, 2014 and 2013, respectively.
	Goodwill
	Goodwill for the Olefins segment was $29,990 at September 30, 2014 and December 31, 2013. Goodwill for the Vinyls segment was $32,026 at September 30, 2014 and December 31, 2013. There were no changes in the carrying amount of goodwill by operating segments for the nine months ended September 30, 2014.

LongTerm_Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Long-Term Debt	'
	Long-Term Debt
	Long-term debt consists of the following:
		September 30,		December 31,
		2014		2013
	3.60% senior notes due 2022	$	249,079	$	248,990
	6 ½% senior notes due 2029	100,000		100,000
	6 ¾% senior notes due 2032	250,000		250,000
	6 ½% senior notes due 2035 (the "6 ½% GO Zone Senior Notes Due 2035")	89,000		89,000
	6 ½% senior notes due 2035 (the "6 ½% IKE Zone Senior Notes Due 2035")	65,000		65,000
	Loan related to tax-exempt waste disposal revenue bonds due 2027	10,889		10,889
	Long-term debt, net	$	763,968	$	763,879
	Revolving Credit Facility
	The Company has a $400,000 senior secured revolving credit facility. In July 2014, the Company entered into a third amendment and restatement to the revolving credit facility. The amendment and restatement extended the scheduled maturity date of the facility from September 16, 2016 to July 17, 2019, reduced the interest rate and facility fee payable under the facility and amended the covenants restricting the Company’s ability to make distributions and acquisitions and make investments, among other things. The facility includes a provision permitting the Company to increase the size of the facility, up to four times, in increments of at least $25,000 each (up to a maximum of $200,000) under certain circumstances if lenders agree to commit to such an increase.
	At September 30, 2014, the Company had no borrowings outstanding under the revolving credit facility. Any borrowings under the facility will bear interest at either LIBOR plus a spread ranging from 1.75% to 1.25%, provided that so long as the Company is rated investment grade, the margin for LIBOR loans will not exceed 1.50%, or a base rate plus a spread ranging from 0.50% to 0.00%. The revolving credit facility also requires an unused commitment fee of 0.25% per annum. All interest rates under the facility are subject to monthly grid pricing adjustments based on prior month average daily loan availability. The revolving credit facility matures on July 17, 2019. As of September 30, 2014, the Company had outstanding letters of credit totaling $32,399 and borrowing availability of $367,601 under the revolving credit facility.
	The Company's revolving credit facility generally restricts the Company's ability to make distributions unless, on a pro forma basis after giving effect to the distribution, the borrowing availability under the facility equals or exceeds the greater of (1) 20% of the commitments under the facility and (2) $80,000; or the borrowing availability under the facility equals or exceeds the greater of (1) 15% of the commitments under the facility and (2) $60,000, and the Company's fixed charge coverage ratio is at least 1.0:1. However, the Company may make specified distributions up to an aggregate of $75,000, to be increased by 5% in 2015, and in each fiscal year thereafter, on an aggregate basis, for each fiscal year.
	In order to make acquisitions or investments, the Company's revolving credit facility generally provides that (1) the Company must maintain a minimum borrowing availability of at least the greater of $60,000 or 15% of the total bank commitments under its revolving credit facility or (2) the Company must maintain a minimum borrowing availability of at least the greater of $50,000 or 12.5% of the total bank commitments under its revolving credit facility and meet a minimum fixed charge coverage ratio of 1.0:1 under its revolving credit facility. Notwithstanding the foregoing, the Company may make investments in the aggregate up to the greater of $50,000 and 1.25% of tangible assets and acquisitions in the aggregate up to the greater of $100,000 and 2.5% of tangible assets, if, on a pro forma basis after giving effect to the acquisition or investment, either (X) the borrowing availability under the facility equals or exceeds the greater of (A) 12.5% of the total bank commitments under the facility and (B) $50,000, but is less than the greater of (A) 15% of the total bank commitments and (B) $60,000, or (Y) the Company's fixed charge coverage ratio is at least 1.0:1.
	The revolving credit facility contains other customary covenants and events of default that impose significant operating and financial restrictions on the Company. These restrictions, among other things, limit the occurrence of additional indebtedness and the Company's ability to create liens, to engage in certain affiliate transactions and to engage in sale-leaseback transactions.

StockBased_Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock-Based Compensation	'
	Stock-Based Compensation
	Under the Westlake Chemical Corporation 2013 Omnibus Incentive Plan (as amended and restated, the "2013 Plan"), all employees and nonemployee directors of the Company, as well as certain individuals who have agreed to become the Company's employees, are eligible for awards. Shares of common stock may be issued as authorized in the 2013 Plan. At the discretion of the administrator of the 2013 Plan, employees and nonemployee directors may be granted awards in the form of stock options, stock appreciation rights, stock awards, restricted stock units or cash awards (any of which may be a performance award). Total stock-based compensation expense related to the 2013 Plan was $2,346 and $1,680 for the three months ended September 30, 2014 and 2013, respectively, and $6,856 and $4,804 for the nine months ended September 30, 2014 and 2013, respectively.

Derivative_Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Instruments	'
	Derivative Instruments
	Commodity Risk Management
	The Company uses derivative instruments to reduce price volatility risk on raw materials and products as a substantial portion of its raw materials and products are commodities whose prices fluctuate as market supply and demand fundamentals change. Business strategies to protect against such instability include ethylene product feedstock flexibility and moving downstream into the olefins and vinyls products where pricing is more stable. The Company does not use derivative instruments to engage in speculative activities.
	For derivative instruments that are designated and qualify as fair value hedges, the gains or losses on the derivative instruments, as well as the offsetting losses or gains on the hedged items attributable to the hedged risk, were included in cost of sales in the consolidated statements of operations for the three and nine months ended September 30, 2013. The Company had no derivative instruments that were designated as fair value hedges for the three and nine months ended September 30, 2014.
	Gains and losses from changes in the fair value of derivative instruments that are not designated as hedging instruments were included in gross profit in the consolidated statements of operations for the three and nine months ended September 30, 2014 and 2013.
	The exposure on commodity derivatives used for price risk management includes the risk that the counterparty will not pay if the market declines below the established fixed price. In such case, the Company would lose the benefit of the derivative differential on the volume of the commodities covered. In any event, the Company would continue to receive the market price on the actual volume hedged. The Company also bears the risk that it could lose the benefit of market improvements over the fixed derivative price for the term and volume of the derivative instruments (as such improvements would accrue to the benefit of the counterparty).
	Disclosures related to the Company's derivative assets and derivative liabilities subject to enforceable master netting arrangements have not been presented as they are not material to the Company's consolidated balance sheets at September 30, 2014 and December 31, 2013.
	The fair values of derivative instruments in the Company's consolidated balance sheets were as follows:
		Derivative Assets
		Balance Sheet Location	Fair Value as of
			September 30,			December 31,
			2014			2013
	Not designated as hedging instruments
	Commodity forward contracts	Accounts receivable, net	$	451		$	296
	Total derivative assets		$	451		$	296
		Derivative Liabilities
		Balance Sheet Location	Fair Value as of
			September 30,			December 31,
			2014			2013
	Not designated as hedging instruments
	Commodity forward contracts	Accrued liabilities	$	6,477		$	176
	Total derivative liabilities		$	6,477		$	176
	The following tables reflect the impact of derivative instruments designated as fair value hedges and the related hedged item on the Company's consolidated statements of operations. For the three and nine months ended September 30, 2013, there was no material ineffectiveness with regard to the Company's qualifying fair value hedges.
	Derivatives in Fair Value	Location of Gain (Loss)	Three Months Ended September 30,						Nine Months Ended September 30,
	Hedging Relationships	Recognized in
		Income on Derivative	2014			2013			2014			2013
	Commodity forward contracts	Cost of sales	$	—		$	(232	)	$	—		$	(342	)
	Hedged Items in Fair Value	Location of Gain (Loss)	Three Months Ended September 30,						Nine Months Ended September 30,
	Hedging Relationships	Recognized in
		Income on Hedged Items	2014			2013			2014			2013
	Firm commitment designated	Cost of sales	$	—		$	236		$	—		$	15
	as the hedged item
	The impact of derivative instruments that have not been designated as hedges on the Company's consolidated statements of operations were as follows:
	Derivatives Not Designated as	Location of Gain (Loss)	Three Months Ended September 30,						Nine Months Ended September 30,
	Hedging Instruments	Recognized in
		Income on Derivative	2014			2013			2014			2013
	Commodity forward contracts	Gross profit	$	(6,937	)	$	4,854		$	(7,308	)	$	9,897
	See Note 10 for the fair value of the Company's derivative instruments.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Fair Value Measurements
	The Company reports certain assets and liabilities at fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). Under the accounting guidance for fair value measurements, inputs used to measure fair value are classified in one of three levels:
	Level 1: Quoted market prices in active markets for identical assets or liabilities.
	Level 2: Observable market-based inputs or unobservable inputs that are corroborated by market data.
	Level 3: Unobservable inputs that are not corroborated by market data.
	The following tables summarize, by level within the fair value hierarchy, the Company's assets and liabilities that were accounted for at fair value on a recurring basis:
		30-Sep-14
		Level 1			Level 2			Total
	Derivative instruments
	Risk management assets - Commodity forward contracts	$	428		$	23		$	451
	Risk management liabilities - Commodity forward contracts	(119		)	(6,358		)	(6,477		)
	Available-for-sale marketable securities	21,066			—			21,066
		December 31, 2013
		Level 1			Level 2			Total
	Derivative instruments
	Risk management assets - Commodity forward contracts	$	48		$	248		$	296
	Risk management liabilities - Commodity forward contracts	—			(176		)	(176		)
	Available-for-sale marketable securities	91,595			147,793			239,388
	The Level 2 measurements for the Company's commodity contracts are derived using forward curves supplied by industry-recognized and unrelated third-party services. The Level 2 measurements for the Company's available-for-sale securities are derived using market-based pricing provided by unrelated third-party services.
	There were no transfers in or out of Levels 1 and 2 of the fair value hierarchy for the nine months ended September 30, 2014 and 2013.
	In addition to the financial assets and liabilities above, the Company has other financial assets and liabilities subject to fair value measures. These financial assets and liabilities include cash and cash equivalents, accounts receivable, net, accounts payable and long-term debt, all of which are recorded at carrying value. The amounts reported in the consolidated balance sheets for cash and cash equivalents, accounts receivable, net and accounts payable approximate their fair value due to the short maturities of these instruments. The carrying and fair values of the Company's long-term debt are summarized in the table below. The Company's long-term debt instruments are publicly-traded. A market approach, based upon quotes from financial reporting services, is used to measure the fair value of the Company's long-term debt. Because the Company's long-term debt instruments may not be actively traded, the inputs used to measure the fair value of the Company's long-term debt are classified as Level 2 inputs within the fair value hierarchy.
		30-Sep-14						December 31, 2013
		Carrying			Fair			Carrying			Fair
		Value			Value			Value			Value
	3.60% senior notes due 2022	$	249,079		$	247,633		$	248,990		$	236,905
	6 ½% senior notes due 2029	100,000			114,624			100,000			109,490
	6 ¾% senior notes due 2032	250,000			275,313			250,000			265,148
	6 ½% GO Zone Senior Notes Due 2035	89,000			101,855			89,000			94,606
	6 ½% IKE Zone Senior Notes Due 2035	65,000			74,389			65,000			69,094
	Loan related to tax-exempt waste disposal revenue	10,889			10,889			10,889			10,889
	bonds due 2027

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	The effective income tax rate was 37.6% for the nine months ended September 30, 2014. The effective income tax rate for the 2014 period was above the U.S. federal statutory rate of 35.0% primarily due to state income taxes, partially offset by the domestic manufacturing deduction. The effective income tax rate was 35.8% for the nine months ended September 30, 2013. The effective income tax rate for the 2013 period was above the U.S. federal statutory rate of 35.0% primarily due to state income taxes, partially offset by the domestic manufacturing deduction.
	There was no material change to the total gross unrecognized tax benefits for the nine months ended September 30, 2014. Management anticipates that all of the gross unrecognized tax benefits of $2,501 will be recognized within the next twelve months due to expiring statutes of limitations. The impact from the recognition of these tax benefits on the Company's effective tax rate is expected to be immaterial.
	The Company recognizes penalties and interest accrued related to unrecognized tax benefits in income tax expense. As of September 30, 2014, the Company had no material accrued interest and penalties related to uncertain tax positions.
	The Company files income tax returns in the U.S. federal jurisdiction, various states and foreign jurisdictions. The Company is no longer subject to examinations by tax authorities before the year 2007.

Earnings_per_Share

Earnings per Share	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Earnings per Share	'
	Earnings per Share
	The Company has unvested shares of restricted stock and restricted stock units outstanding that are considered participating securities and, therefore, computes basic and diluted earnings per share under the two-class method. Basic earnings per share for the periods are based upon the weighted average number of shares of common stock outstanding during the periods. Diluted earnings per share include the effect of certain stock options.
			Three Months Ended September 30,						Nine Months Ended September 30,
			2014			2013			2014			2013
	Net income attributable to Westlake Chemical		$	167,757		$	170,290		$	495,232		$	439,453
	Corporation
	Less:
	Net income attributable to participating securities		(353		)	(587		)	(1,099		)	(1,691		)
	Net income attributable to common shareholders		$	167,404		$	169,703		$	494,133		$	437,762
	The following table reconciles the denominator for the basic and diluted earnings per share computations shown in the consolidated statements of operations:
			Three Months Ended September 30,						Nine Months Ended September 30,
			2014			2013			2014			2013
	Weighted average common shares—basic (1)		133,299,458			133,257,494			133,199,304			133,256,054
	Plus incremental shares from:
	Assumed exercise of options (1)		546,601			553,614			543,841			550,704
	Weighted average common shares—diluted (1)		133,846,059			133,811,108			133,743,145			133,806,758
	Earnings per common share attributable to
	Westlake Chemical Corporation : (1)
	Basic		$	1.26		$	1.28		$	3.71		$	3.29
	Diluted		$	1.25		$	1.27		$	3.69		$	3.27
	_____________
	-1	Share amounts and per share data for the three and nine months ended September 30, 2013 have been restated to reflect the effect of a two-for-one stock split on March 18, 2014. See Note 1 for additional information.
	There were no options excluded from the computation of diluted earnings per share for the three and nine months ended September 30, 2014. Excluded from the computation of diluted earnings per share for the three and nine months ended September 30, 2013 are options to purchase 137,324 and 115,518 shares of common stock, respectively. These options were outstanding during the periods reported but were excluded because the effect of including them would have been antidilutive.

Pension_and_PostRetirement_Ben

Pension and Post-Retirement Benefit Costs	9 Months Ended
	Sep. 30, 2014
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]	'
Pension and Post-Retirement Benefit Costs	'
	Pension and Post-Retirement Benefit Costs
	Components of net periodic benefit cost are as follows:
		Three Months Ended September 30,										Nine Months Ended September 30,
		Pension						Post-retirement				Pension						Post-retirement
								Healthcare										Healthcare
		2014			2013			2014		2013		2014			2013			2014		2013
	Service cost	$	331		$	275		$	6	$	2	$	498		$	815		$	16	$	7
	Interest cost	1,138			515			185		147		2,309			1,531			548		442
	Expected return on	(777		)	(713		)	—		—		(2,363		)	(2,140		)	—		—
	plan assets
	Amortization of prior	74			74			13		21		223			223			38		63
	service cost
	Amortization of net loss	71			510			82		90		204			1,449			220		269
	Net periodic benefit cost	$	837		$	661		$	286	$	260	$	871		$	1,878		$	822	$	781
	The Company contributed $2,447 and $776 to the Salaried pension plan in the first nine months of 2014 and 2013, respectively, and contributed $916 and $640 to the Wage pension plan in the first nine months of 2014 and 2013, respectively. The Company expects to make additional contributions of $330 to the Salaried pension plan and $290 to the Wage pension plan during the fiscal year ending December 31, 2014.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Accumulated Other Comprehensive Income	'
	Accumulated Other Comprehensive Loss
	Changes in accumulated other comprehensive income (loss) by component for the nine months ended September 30, 2014 and 2013 were as follows:
			Benefits				Cumulative				Net Unrealized				Total
			Liability,				Foreign				Holding Gains
			Net of Tax				Currency				on Investments,
							Exchange				Net of Tax
	Balances at December 31, 2013		$	(6,696	)		$	3,904			$	176			$	(2,616	)
	Other comprehensive (loss) income before		(39		)		(37,882		)		4,459				(33,462		)
	reclassifications
	Amounts reclassified from accumulated other		422				—				(777		)		(355		)
	comprehensive loss
	Net other comprehensive income (loss) for the period		383				(37,882		)		3,682				(33,817		)
	Balances at September 30, 2014		$	(6,313	)		$	(33,978	)		$	3,858			$	(36,433	)
			Benefits				Cumulative				Net Unrealized				Total
			Liability,				Foreign				Holding Gains
			Net of Tax				Currency				on Investments,
							Exchange				Net of Tax
	Balances at December 31, 2012		$	(16,351	)		$	5,511			$	—			$	(10,840	)
	Other comprehensive (loss) income before		(601		)		(844		)		131				(1,314		)
	reclassifications
	Amounts reclassified from accumulated other		1,233				—				—				1,233
	comprehensive loss
	Net other comprehensive income (loss) for the period		632				(844		)		131				(81		)
	Balances at September 30, 2013		$	(15,719	)		$	4,667			$	131			$	(10,921	)
	The following table provides the details of the amounts reclassified from accumulated other comprehensive income (loss) into net income in the consolidated statements of operations for the three and nine months ended September 30, 2014 and 2013:
	Details about Accumulated Other Comprehensive		Location of Reclassification		Three Months Ended September 30,								Nine Months Ended September 30,
	Income (Loss) Components		(Income (Expense)) in
			Consolidated Statements
			of Operations		2014				2013				2014				2013
	Amortization of pension and
	other post-retirement items
	Prior service costs		-1		$	(87	)		$	(95	)		$	(261	)		$	(286	)
	Net loss		-1		(153		)		(600		)		(424		)		(1,718		)
					(240		)		(695		)		(685		)		(2,004		)
			Provision for income		92				267				263				771
			taxes
					(148		)		(428		)		(422		)		(1,233		)
	Net unrealized gains on
	available-for-sale
	investments
	Realized gain on		Other income, net		—				—				1,212				—
	available-for-sale
	investments
			Provision for income		—				—				(435		)		—
			taxes
					—				—				$	777			$	—
	Total reclassifications for				$	(148	)		$	(428	)		$	355			$	(1,233	)
	the period
	_____________
	-1	These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. For additional information, please read Note 10 (Employee Benefits) to the financial statements included in the 2013 Form 10-K.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	The Company is subject to environmental laws and regulations that can impose civil and criminal sanctions and that may require it to mitigate the effects of contamination caused by the release or disposal of hazardous substances into the environment. Under one law, the U.S. Comprehensive Environmental Response, Compensation, and Liability Act ("CERCLA"), an owner or operator of property may be held strictly liable for remediating contamination without regard to whether that person caused the contamination, and without regard to whether the practices that resulted in the contamination were legal at the time they occurred. Because several of the Company's production sites have a history of industrial use, it is impossible to predict precisely what effect these legal requirements will have on the Company.
	Contract Disputes with Goodrich and PolyOne. In connection with the 1990 and 1997 acquisitions of the Goodrich Corporation ("Goodrich") chemical manufacturing complex in Calvert City, Kentucky, Goodrich agreed to indemnify the Company for any liabilities related to preexisting contamination at the complex. For its part, the Company agreed to indemnify Goodrich for post-closing contamination caused by the Company's operations. The soil and groundwater at the complex, which does not include the Company's nearby polyvinyl chloride ("PVC") facility, had been extensively contaminated under Goodrich's operations. In 1993, Goodrich spun off the predecessor of PolyOne Corporation ("PolyOne"), and that predecessor assumed Goodrich's indemnification obligations relating to preexisting contamination.
	In 2003, litigation arose among the Company, Goodrich and PolyOne with respect to the allocation of the cost of remediating contamination at the site. The parties settled this litigation in December 2007 and the case was dismissed. In the settlement the parties agreed that, among other things: (1) PolyOne would pay 100% of the costs (with specified exceptions), net of recoveries or credits from third parties, incurred with respect to environmental issues at the Calvert City site from August 1, 2007 forward; (2) either the Company or PolyOne might, from time to time in the future (but not more than once every five years), institute an arbitration proceeding to adjust that percentage; and (3) the Company and PolyOne would negotiate a new environmental remediation utilities and services agreement to cover the Company's provision to, or on behalf of, PolyOne of certain environmental remediation services at the site. The current environmental remediation activities at the Calvert City complex do not have a specified termination date but are expected to last for the foreseeable future. The costs incurred by the Company that have been invoiced to PolyOne to provide the environmental remediation services were $3,284 in 2013. By letter dated March 16, 2010, PolyOne notified the Company that it was initiating an arbitration proceeding under the settlement agreement. In this proceeding, PolyOne seeks to readjust the percentage allocation of costs and to recover approximately $1,400 from the Company in reimbursement of previously paid remediation costs. The arbitration is currently stayed.
	State Administrative Proceedings. There are several administrative proceedings in Kentucky involving the Company, Goodrich and PolyOne related to the same manufacturing complex in Calvert City. In 2003, the Kentucky Environmental and Public Protection Cabinet (the "Cabinet") re-issued Goodrich's Resource Conservation and Recovery Act ("RCRA") permit which requires Goodrich to remediate contamination at the Calvert City manufacturing complex. Both Goodrich and PolyOne challenged various terms of the permit in an attempt to shift Goodrich's clean-up obligations under the permit to the Company. The Company intervened in the proceedings. The Cabinet has suspended all corrective action under the RCRA permit in deference to a remedial investigation and feasibility study ("RIFS") being conducted, under the auspices of the U.S. Environmental Protection Agency ("EPA"), pursuant to an Administrative Settlement Agreement ("AOC"), which became effective on December 9, 2009. See "Federal Administrative Proceedings" below. The proceedings have been postponed. Periodic status conferences will be held to evaluate whether additional proceedings will be required.
	Federal Administrative Proceedings. In May 2009, the Cabinet sent a letter to the EPA requesting the EPA's assistance in addressing contamination at the Calvert City site under CERCLA. In its response to the Cabinet also in May 2009, the EPA stated that it concurred with the Cabinet's request and would incorporate work previously conducted under the Cabinet's RCRA authority into the EPA's cleanup efforts under CERCLA. Since 1983, the EPA has been addressing contamination at an abandoned landfill adjacent to the Company's plant which had been operated by Goodrich and which was being remediated pursuant to CERCLA. During the past three years, the EPA has directed Goodrich and PolyOne to conduct additional investigation activities at the landfill and at the Company's plant. In June 2009, the EPA notified the Company that the Company may have potential liability under section 107(a) of CERCLA at its plant site. Liability under section 107(a) of CERCLA is strict and joint and several. The EPA also identified Goodrich and PolyOne, among others, as potentially responsible parties at the plant site. The Company negotiated, in conjunction with the other potentially responsible parties, the AOC and an order to conduct the RIFS. On July 12, 2013, the parties submitted separate draft RIFS reports to the EPA. The EPA has hired a contractor to complete the remedial investigation report.
	Monetary Relief. Except as noted above with respect to the settlement of the contract litigation among the Company, Goodrich and PolyOne, none of the court, the Cabinet nor the EPA has established any allocation of the costs of remediation among the various parties that are involved in the judicial and administrative proceedings discussed above. At this time, the Company is not able to estimate the loss or reasonable possible loss, if any, on the Company's financial statements that could result from the resolution of these proceedings. Any cash expenditures that the Company might incur in the future with respect to the remediation of contamination at the complex would likely be spread out over an extended period. As a result, the Company believes it is unlikely that any remediation costs allocable to it will be material in terms of expenditures made in any individual reporting period.
	In addition to the matters described above, the Company is involved in various routine legal proceedings incidental to the conduct of its business. The Company does not believe that any of these routine legal proceedings will have a material adverse effect on its financial condition, results of operations or cash flows.

Share_Capital

Share Capital	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Share Capital	'
	Share Capital
	Common Stock
	On May 16, 2014, the stockholders of the Company approved an amendment to the Company's Amended and Restated Certificate of Incorporation to increase the Company's authorized shares of common stock from 150,000,000 shares to 300,000,000 shares, par value $0.01 per share. The Company is now authorized to issue 300,000,000 shares of common stock, par value $0.01 per share, of which 134,680,164 and 134,580,208 shares (on a post-split basis) were issued as of September 30, 2014 and December 31, 2013, respectively. Each share of common stock entitles the holder to one vote on all matters on which holders are permitted to vote, including the election of directors.
	Stock Repurchase Program
	In August 2011, the Company's Board of Directors authorized a stock repurchase program of the Company’s common stock totaling $100,000 (the "2011 Program"). Purchases under the 2011 Program began in September 2011. As of September 30, 2014 and December 31, 2013, the Company had repurchased 1,357,085 and 1,252,922 shares, respectively, of its common stock (on a post-split basis) under this program. Shares repurchased under the 2011 Program are held by the Company as treasury stock and may be used for general corporate purposes, including for the 2013 Omnibus Incentive Plan. Beginning in May 2014, the Company began issuing treasury shares to employees and nonemployee directors for options exercised and for the settlement of restricted stock units. The cost of treasury shares issued was determined using the specific identification method.

Supplemental_Information

Supplemental Information	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Supplemental Information	'
	Supplemental Information
	Other Liabilities
	Other liabilities were $153,158 and $35,593 at September 30, 2014 and December 31, 2013, respectively. Non-current pension obligation, which is a component of other liabilities, was $117,293 and $8,710 at September 30, 2014 and December 31, 2013, respectively. No other component of other liabilities was more than five percent of total liabilities.

Segment_Information

Segment Information	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Segment Information	'
	Segment Information
	The Company operates in two principal operating segments: Olefins and Vinyls. These segments are strategic business units that offer a variety of different products. The Company manages each segment separately as each business requires different technology and marketing strategies.
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Net external sales
	Olefins
	Polyethylene	$	498,450		$	460,105		$	1,461,097		$	1,294,566
	Styrene, feedstock and other	204,647			219,234			663,851			590,959
	Total Olefins	703,097			679,339			2,124,948			1,885,525
	Vinyls
	PVC, caustic soda and other	416,771			212,041			776,060			612,391
	Building products	133,359			112,785			378,471			309,943
	Total Vinyls	550,130			324,826			1,154,531			922,334
		$	1,253,227		$	1,004,165		$	3,279,479		$	2,807,859
	Intersegment sales
	Olefins	$	26,518		$	85,454		$	118,153		$	230,607
	Vinyls	355			403			1,029			1,111
		$	26,873		$	85,857		$	119,182		$	231,718
	Income (loss) from operations
	Olefins	$	259,277		$	237,239		$	770,267		$	585,958
	Vinyls	59,445			39,554			76,460			136,123
	Corporate and other	(11,961		)	(10,191		)	(25,123		)	(26,197		)
		$	306,761		$	266,602		$	821,604		$	695,884
	Depreciation and amortization
	Olefins	$	26,443		$	26,515		$	79,811		$	76,415
	Vinyls	27,336			14,089			68,127			39,507
	Corporate and other	141			124			456			372
		$	53,920		$	40,728		$	148,394		$	116,294
	Other income (expense), net
	Olefins	$	1,609		$	728		$	4,262		$	5,889
	Vinyls	1,189			(742		)	942			(1,687		)
	Corporate and other	(5,468		)	(273		)	(764		)	(1,065		)
		$	(2,670	)	$	(287	)	$	4,440		$	3,137
	Provision for (benefit from) income taxes
	Olefins	$	105,030		$	82,553		$	282,082		$	208,170
	Vinyls	21,761			10,710			22,121			44,120
	Corporate and other	(2,342		)	(535		)	(3,972		)	(7,643		)
		$	124,449		$	92,728		$	300,231		$	244,647
	Capital expenditures
	Olefins	$	48,519		$	27,577		$	121,041		$	105,656
	Vinyls	44,067			172,565			187,449			391,864
	Corporate and other	1,685			276			2,693			770
		$	94,271		$	200,418		$	311,183		$	498,290
	A reconciliation of total segment income from operations to consolidated income before income taxes is as follows:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Income from operations	$	306,761		$	266,602		$	821,604		$	695,884
	Interest expense	(9,486		)	(3,297		)	(28,182		)	(14,921		)
	Other (expense) income, net	(2,670		)	(287		)	4,440			3,137
	Income before income taxes	$	294,605		$	263,018		$	797,862		$	684,100
		September 30,			December 31,
		2014			2013
	Total assets
	Olefins	$	1,740,878		$	1,557,510
	Vinyls	2,898,250			1,740,595
	Corporate and other	487,155			762,804
		$	5,126,283		$	4,060,909

Westlake_Chemical_Partners_LP

Westlake Chemical Partners LP	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Westlake Chemical Partners LP	'
	Westlake Chemical Partners LP
	Westlake Chemical Partners LP ("WLKP") is a publicly traded master limited partnership that was formed by the Company to operate, acquire and develop ethylene production facilities and related assets.
	Initial Public Offering of WLKP
	On August 4, 2014, WLKP completed its initial public offering of 12,937,500 common units at a price of $24.00 per unit, which included 1,687,500 units purchased by the underwriters pursuant to the exercise in full of their over-allotment option. Net proceeds to WLKP from the sale of the units was approximately $286,088, net of underwriting discounts, structuring fees and offering expenses (the "Offering Costs") of approximately $24,412. At the consummation of the offering, WLKP's assets consist of a 10.6% limited partner interest in Westlake Chemical OpCo LP ("OpCo"), as well as the general partner interest in OpCo. The Company retained an 89.4% limited partner interest in OpCo and a significant interest in WLKP. The Company consolidates WLKP for financial reporting purposes as the Company has a controlling financial interest. The initial public offering represented the sale of 47.8% of the common and subordinated units in WLKP. OpCo used the net proceeds from the purchase of its limited partner interest to establish a cash reserve of approximately $55,419 for turnaround expenditures, to reimburse approximately $151,729 for capital expenditures incurred by the Company with respect to certain of the assets contributed to OpCo and to repay intercompany debt to the Company of approximately $78,940.
	The following table is a reconciliation of proceeds from the initial public offering:
	Total proceeds from the initial public offering	$	310,500
	Less: Offering Costs	(24,412		)
	Net proceeds from the initial public offering	286,088
	Less: Cash retained by OpCo	(55,419		)
	Net proceeds distributed to the Company from the initial public offering	$	230,669

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Acquisition	'
	Acquisition
	On July 31, 2014, the Company acquired all the equity interests in German-based Vinnolit Holdings GmbH and its subsidiary companies ("Vinnolit") from several entities associated with Advent International Corporation (the "Sellers"). Vinnolit is headquartered in Ismaning, Germany and is an integrated global leader in specialty PVC resins, with a combined annual capacity of 1.7 billion pounds of PVC, including specialty paste and suspension grades, 1.5 billion pounds of vinyl chloride monomer ("VCM") and 1.0 billion pounds of caustic soda. The Vinnolit acquisition comprised six production facilities located in Burghausen, Gendorf, Cologne, Knapsack and Schkopau in Germany and Hillhouse in the United Kingdom. The Company also acquired Vinnolit's technical centers, including a research and development facility in Gendorf and an applications laboratory in Burghausen. The Company’s management believes that this strategic acquisition will enhance its strategy of integration and expansion into new markets and specialty products, in addition to growing the Company's global presence with a footprint in Europe and surrounding markets.
	The purchase price of $736,224 was paid with available cash on hand. The acquisition is being accounted for under the acquisition method of accounting. The assets acquired and liabilities assumed and the results of operations of this acquired business are included in the Vinyls segment.
	The acquired business contributed net sales and net loss of $195,477 and $2,992, respectively, to the Company for the period from July 31, 2014 to September 30, 2014. The following unaudited consolidated pro forma information presents consolidated information as if the acquisition had occurred on January 1, 2013:
			Pro Forma
			Nine Months Ended
			September 30,
			2014			2013
	Net sales		$	4,016,935		$	3,747,619
	Net income		$	550,667		$	480,964
	Net income attributable to noncontrolling interests		2,399			—
	Net income attributable to Westlake Chemical Corporation		$	548,268		$	480,964
	Earnings per common share attributable to Westlake Chemical Corporation:
	Basic		$	4.11		$	3.59
	Diluted		$	4.09		$	3.58
	The pro forma amounts above have been calculated after applying the Company’s accounting policies and adjusting the Vinnolit results to reflect (1) the additional depreciation and amortization that would have been charged assuming the fair value adjustments to property, plant and equipment and intangible assets had been applied from January 1, 2013; (2) the elimination of interest expense assuming the long-term debt paid off on behalf of the Sellers as of the acquisition date had been retired as of January 1, 2013; (3) the elimination of transaction-related costs; and (4) an adjustment to tax-effect the aforementioned pro forma adjustments using an estimated aggregate statutory income tax rate of the jurisdictions to which the above adjustments relate. The pro forma amounts do not include any potential synergies, cost savings or other expected benefits of the Vinnolit acquisition, are presented for illustrative purposes only and are not necessarily indicative of results that would have been achieved if the acquisition had occurred as of January 1, 2013 or of future operating performance.
	For the nine months ended September 30, 2014, the Company recognized $11,235 of transaction-related costs. These costs are included in general and administrative expenses and other income, net in the consolidated statement of operations for the nine months ended September 30, 2014. The transaction-related costs included in other income, net pertained to losses incurred on forward foreign exchange contracts for the purchase consideration of Vinnolit.
	The following table summarizes the purchase consideration transferred and the estimated fair value of identified assets acquired and liabilities assumed at the date of acquisition. The preliminary allocation of the purchase consideration is based on management’s estimates, judgments and assumptions. These estimates, judgments and assumptions are subject to change upon final valuation and should be treated as preliminary values. Management estimated that the fair value of the net assets acquired equals consideration paid. Therefore, no goodwill was recorded. The final allocation of purchase consideration could include changes in the estimated fair value of (1) inventories; (2) property, plant and equipment; (3) equity investments; (4) trademark and trade name, developed technologies and customer relationships; (5) power purchase agreement liability; and (6) deferred income taxes.
	Fair value of consideration transferred:
	Cash paid to Sellers		$	309,619
	Cash deposited in escrow (1)		13,390
	Retirement of long-term debt as of July 31, 2014, on behalf of the Sellers (2)		413,215
	Total purchase consideration		$	736,224
	Preliminary allocation of consideration transferred to net assets acquired:
	Cash		$	125,137
	Working capital, excluding inventory and cash (3)		23,072
	Inventories (4)		114,961
	Property, plant and equipment		471,123
	Investments		51,552
	Other assets (5)		65,366
	Intangible assets:
	Trademarks and trade name (weighted average life of 20 years)		40,170
	Developed technologies (weighted average life of 20 years)		31,600
	Other intangibles (weighted average life of 9.4 years)		1,422
	Deferred income tax asset - current		8,697
	Deferred income tax asset - non-current		27,387
	Pension obligation		(117,970		)
	Other long-term liabilities		(10,723		)
	Power purchase agreement liability (6)		(10,826		)
	Deferred income tax liability - current		(6,845		)
	Deferred income tax liability - non-current		(77,899		)
	Total identifiable net assets		736,224
	Goodwill (7)		—
	Consideration transferred		$	736,224
	_____________
	-1	None of the cash held in escrow is considered contingent consideration as it is expected to be released to the Sellers pending the Sellers’ satisfaction of general representations and warranties made in connection with the execution of the purchase agreement.
	-2	Vinnolit’s long-term debt paid on behalf of the Sellers was not legally assumed by Westlake in the acquisition and was a condition of the consummation of the purchase agreement. Therefore, the retirement has been included in the total purchase consideration.
	-3	The fair value of accounts receivable acquired is $181,826, with the gross contractual amount being $183,769. The Company expects $1,943 to be uncollectible.
	-4	An adjustment of approximately $16,900 was recorded to reflect Vinnolit's inventories at fair value and increased cost of sales by the same amount for the three months ended September 30, 2014.
	-5	Included in other assets was a loan acquired that was repaid prior to September 30, 2014.
	-6	A liability arising from unfavorable forward purchase contracts for the purchase of power was recognized at fair value. This liability will be amortized over a period of approximately 3.0 years, being the weighted-average life of the forward purchase contracts.
	-7	Management estimated that the fair value of the net assets acquired equals consideration paid. Therefore, no goodwill was recorded.

Related_Party_and_Affiliate_Tr

Related Party and Affiliate Transactions	9 Months Ended
	Sep. 30, 2014
Related Party Transactions [Abstract]	'
Related Party and Affiliate Transactions	'
	Related Party and Affiliate Transactions
	InfraServ Knapsack GmbH & Co. KG, an on-site chemical complex provider in which the Company owns a 15% equity stake, provides electricity and technical services to the Company's Knapsack, Germany production facility. For the period from July 31, 2014 to September 30, 2014, the Company incurred charges aggregating approximately $11,581.
	InfraServ Gendorf GmbH & Co. KG, an on-site chemical complex provider in which the Company owns an 11% equity stake, provides electricity and technical services to the Company's Gendorf, Germany production facility. For the period from July 31, 2014 to September 30, 2014, the Company incurred charges aggregating approximately $10,489.

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	Subsequent events were evaluated through the date on which the financial statements were issued.

Guarantor_Disclosures

Guarantor Disclosures	9 Months Ended
	Sep. 30, 2014
Guarantees [Abstract]	'
Guarantor Disclosures	'
	ndensed Consolidating Financial Information as of September 30, 2014
		Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
		Chemical			Guarantor			(Less Than			Guarantor
		Corporation			Subsidiaries			100% Owned			Subsidiaries
								Guarantor
								Subsidiary)
	Balance Sheet
	Current assets
	Cash and cash equivalents	$	652,709		$	1,644		$	89,144		$	69,971		$	—		$	813,468
	Accounts receivable, net	15,064			1,377,250			58,106			170,833			(1,028,289		)	592,964
	Inventories	—			385,826			5,551			109,175			—			500,552
	Prepaid expenses and other current assets	137			14,737			303			3,707			—			18,884
	Deferred income taxes	342			25,446			—			292			—			26,080
	Total current assets	668,252			1,804,903			153,104			353,978			(1,028,289		)	1,951,948
	Property, plant and equipment, net	—			1,451,807			806,648			452,020			—			2,710,475
	Equity investments	3,878,703			1,207,569			—			356,286			(5,371,730		)	70,828
	Other assets, net	34,847			351,271			61,679			137,990			(192,755		)	393,032
	Total assets	$	4,581,802		$	4,815,550		$	1,021,431		$	1,300,274		$	(6,592,774	)	$	5,126,283
	Current liabilities
	Accounts payable	$	979,414		$	157,562		$	29,856		$	100,129		$	(1,003,596	)	$	263,365
	Accrued liabilities	15,448			238,225			3,412			77,279			(24,693		)	309,671
	Total current liabilities	994,862			395,787			33,268			177,408			(1,028,289		)	573,036
	Long-term debt	753,079			10,889			188,523			—			(188,523		)	763,968
	Deferred income taxes	—			473,343			1,507			43,155			(4,232		)	513,773
	Other liabilities	—			31,616			—			121,542			—			153,158
	Total liabilities	1,747,941			911,635			223,298			342,105			(1,221,044		)	2,003,935
	Total Westlake Chemical Corporation stockholders' equity	2,833,861			3,903,915			798,133			669,682			(5,371,730		)	2,833,861
	Noncontrolling interests	—			—			—			288,487			—			288,487
	Total equity	2,833,861			3,903,915			798,133			958,169			(5,371,730		)	3,122,348
	Total liabilities and equity	$	4,581,802		$	4,815,550		$	1,021,431		$	1,300,274		$	(6,592,774	)	$	5,126,283
	Condensed Consolidating Financial Information as of December 31, 2013
		Westlake			100% Owned			OpCo			Non-Guarantor			Eliminations			Consolidated
		Chemical			Guarantor			(Less Than			Subsidiaries
		Corporation			Subsidiaries			100% Owned
								Guarantor
								Subsidiary)
	Balance Sheet
	Current assets
	Cash and cash equivalents	$	420,948		$	6,227		$	—		$	34,126		$	—		$	461,301
	Marketable securities	239,388			—			—			—			—			239,388
	Accounts receivable, net	3,879			666,344			71,812			2,755			(316,333		)	428,457
	Inventories	—			339,929			116,377			15,573			—			471,879
	Prepaid expenses and other current assets	778			11,055			257			1,798			—			13,888
	Deferred income taxes	441			28,974			4,448			306			—			34,169
	Total current assets	665,434			1,052,529			192,894			54,558			(316,333		)	1,649,082
	Property, plant and equipment, net	—			1,318,119			762,972			6,923			—			2,088,014
	Equity investments	2,815,752			636,461			10,411			31,518			(3,427,267		)	66,875
	Other assets, net	15,393			423,901			75,197			1,199			(258,752		)	256,938
	Total assets	$	3,496,579		$	3,431,010		$	1,041,474		$	94,198		$	(4,002,352	)	$	4,060,909
	Current liabilities
	Accounts payable	$	316,652		$	100,570		$	122,564		$	10,649		$	(300,822	)	$	249,613
	Accrued liabilities	8,334			134,452			26,688			1,282			(15,511		)	155,245
	Total current liabilities	324,986			235,022			149,252			11,931			(316,333		)	404,858
	Long-term debt	752,990			10,889			252,973			—			(252,973		)	763,879
	Deferred income taxes	—			260,171			182,855			729			(5,779		)	437,976
	Other liabilities	—			34,571			962			60			—			35,593
	Total equity	2,418,603			2,890,357			455,432			81,478			(3,427,267		)	2,418,603
	Total liabilities and equity	$	3,496,579		$	3,431,010		$	1,041,474		$	94,198		$	(4,002,352	)	$	4,060,909
	Condensed Consolidating Financial Information for the Three Months Ended September 30, 2014
		Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
		Chemical			Guarantor			(Less Than			Guarantor
		Corporation			Subsidiaries			100% Owned			Subsidiaries
								Guarantor
						Subsidiary)
Statement of Operations
Net sales	$	—		$	1,026,282		$	392,008		$	208,313		$	(373,376	)	$	1,253,227
Cost of sales	—			831,675			227,015			202,110			(369,093		)	891,707
Gross profit	—			194,607			164,993			6,203			(4,283		)	361,520
Selling, general and administrative expenses	399			36,445			8,014			14,184			(4,283		)	54,759
(Loss) income from operations	(399		)	158,162			156,979			(7,981		)	—			306,761
Interest expense	(10,343		)	(2		)	(2,137		)	(39		)	3,035			(9,486		)
Other income (expense), net	2,138			(2,942		)	486			683			(3,035		)	(2,670		)
(Loss) income before income taxes	(8,604		)	155,218			155,328			(7,337		)	—			294,605
(Benefit from) provision for income taxes	(3,088		)	93,366			36,309			(2,138		)	—			124,449
Equity in net income of subsidiaries	173,273			113,157			—			5,862			(292,292		)	—
Net income (loss)	167,757			175,009			119,019			663			(292,292		)	170,156
Net income attributable to noncontrolling interests	—			—			—			2,399			—			2,399
Net income (loss) attributable to Westlake Chemical Corporation	$	167,757		$	175,009		$	119,019		$	(1,736	)	$	(292,292	)	$	167,757
Comprehensive income (loss) attributable to Westlake Chemical	$	131,456		$	175,137		$	119,019		$	(39,528	)	$	(254,628	)	$	131,456
Corporation
Condensed Consolidating Financial Information for the Three Months Ended September 30, 2013
	Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
	Chemical			Guarantor			(Less Than			Guarantor
	Corporation			Subsidiaries			100% Owned			Subsidiaries
							Guarantor
							Subsidiary)
Statement of Operations
Net sales	$	—		$	844,081		$	540,133		$	13,337		$	(393,386	)	$	1,004,165
Cost of sales	—			754,037			327,152			11,891			(393,386		)	699,694
Gross profit	—			90,044			212,981			1,446			—			304,471
Selling, general and administrative expenses	514			29,323			6,391			1,641			—			37,869
(Loss) income from operations	(514		)	60,721			206,590			(195		)	—			266,602
Interest expense	(3,292		)	(5		)	(2,295		)	—			2,295			(3,297		)
Other income (expense), net	3,585			(2,688		)	1,162			(51		)	(2,295		)	(287		)
(Loss) income before income taxes	(221		)	58,028			205,457			(246		)	—			263,018
(Benefit from) provision for income taxes	(70		)	19,973			72,876			(51		)	—			92,728
Equity in net income of subsidiaries	170,441			132,581			—			—			(303,022		)	—
Net income (loss) attributable to Westlake Chemical Corporation	$	170,290		$	170,636		$	132,581		$	(195	)	$	(303,022	)	$	170,290
Comprehensive income attributable to Westlake Chemical	$	171,095		$	170,764		$	132,581		$	351		$	(303,696	)	$	171,095
Corporation
Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2014
	Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
	Chemical			Guarantor			(Less Than			Guarantor
	Corporation			Subsidiaries			100% Owned			Subsidiaries
							Guarantor
							Subsidiary)
Statement of Operations
Net sales	$	—		$	2,809,844		$	1,476,157		$	229,183		$	(1,235,705	)	$	3,279,479
Cost of sales	—			2,476,608			832,304			221,233			(1,205,167		)	2,324,978
Gross profit	—			333,236			643,853			7,950			(30,538		)	954,501
Selling, general and administrative expenses	1,474			123,050			21,957			16,954			(30,538		)	132,897
(Loss) income from operations	(1,474		)	210,186			621,896			(9,004		)	—			821,604
Interest expense	(29,032		)	(8		)	(9,833		)	(39		)	10,730			(28,182		)
Other income (expense), net	14,488			(1,729		)	3,135			(724		)	(10,730		)	4,440
(Loss) income before income taxes	(16,018		)	208,449			615,198			(9,767		)	—			797,862
(Benefit from) provision for income taxes	(5,686		)	109,920			198,461			(2,464		)	—			300,231
Equity in net income of subsidiaries	505,564			410,875			—			5,862			(922,301		)	—
Net income (loss)	495,232			509,404			416,737			(1,441		)	(922,301		)	497,631
Net income attributable to noncontrolling interests	—			—			—			2,399			—			2,399
Net income (loss) attributable to Westlake Chemical Corporation	$	495,232		$	509,404		$	416,737		$	(3,840	)	$	(922,301	)	$	495,232
Comprehensive income (loss) attributable to Westlake Chemical	$	461,415		$	509,787		$	416,737		$	(41,722	)	$	(884,802	)	$	461,415
Corporation
Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2013
	Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
	Chemical			Guarantor			(Less Than			Guarantor
	Corporation			Subsidiaries			100% Owned			Subsidiaries
							Guarantor
							Subsidiary)
Statement of Operations
Net sales	$	—		$	2,407,341		$	1,565,809		$	37,561		$	(1,202,852	)	$	2,807,859
Cost of sales	—			2,247,338			924,663			32,943			(1,202,852		)	2,002,092
Gross profit	—			160,003			641,146			4,618			—			805,767
Selling, general and administrative expenses	1,576			84,152			19,326			4,829			—			109,883
(Loss) income from operations	(1,576		)	75,851			621,820			(211		)	—			695,884
Interest expense	(14,882		)	(39		)	(4,893		)	—			4,893			(14,921		)
Other income (expense), net	7,490			(4,002		)	6,422			(1,880		)	(4,893		)	3,137
(Loss) income before income taxes	(8,968		)	71,810			623,349			(2,091		)	—			684,100
(Benefit from) provision for income taxes	(3,202		)	27,292			221,009			(452		)	—			244,647
Equity in net income of subsidiaries	445,219			402,340			—			—			(847,559		)	—
Net income (loss) attributable to Westlake Chemical Corporation	$	439,453		$	446,858		$	402,340		$	(1,639	)	$	(847,559	)	$	439,453
Comprehensive income (loss) attributable to Westlake Chemical	$	439,372		$	447,490		$	402,340		$	(2,483	)	$	(847,347	)	$	439,372
Corporation
Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2014
	Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
	Chemical			Guarantor			(Less Than			Guarantor
	Corporation			Subsidiaries			100% Owned			Subsidiaries
							Guarantor
							Subsidiary)
Statement of Cash Flows
Cash flows from operating activities
Net income (loss)	$	495,232		$	509,404		$	416,737		$	(1,441	)	$	(922,301	)	$	497,631
Adjustments to reconcile net income (loss) to net cash (used for)
provided by operating activities
Depreciation and amortization	1,172			82,597			58,501			7,296			—			149,566
Deferred income taxes	(418		)	26,991			8,267			(381		)	—			34,459
Net changes in working capital and other	(509,862		)	(919,521		)	1,641			599,909			922,301			94,468
Net cash (used for) provided by operating activities	(13,876		)	(300,529		)	485,146			605,383			—			776,124
Cash flows from investing activities
Acquisition of business, net of cash acquired	—			—			—			(611,087		)	—			(611,087		)
Additions to property, plant and equipment	—			(160,147		)	(144,348		)	(6,688		)	—			(311,183		)
Proceeds from disposition of assets	—			144			—			1			—			145
Proceeds from repayment of loan acquired	—			—			—			45,923			—			45,923
Proceeds from sales and maturities of securities	342,045			—			—			—			—			342,045
Purchase of securities	(117,332		)	—			—			—			—			(117,332		)
Settlements of derivative instruments	—			(556		)	(133		)	—			—			(689		)
Net cash provided by (used for) investing activities	224,713			(160,559		)	(144,481		)	(571,851		)	—			(652,178		)
Cash flows from financing activities
Intercompany financing	75,104			(143,325		)	62,221			6,000			—			—
Net distributions prior to WLKP initial public offering	—			448,101			(448,101		)	—			—			—
Capitalized debt issuance costs	(1,167		)	—			—			—			—			(1,167		)
Dividends paid	(55,690		)	151,729			(151,729		)	—			—			(55,690		)
Net proceeds from issuance of WLKP common units	—			—			—			286,088			—			286,088
Purchase of limited partner interests	—			—			286,088			(286,088		)	—			—
Proceeds from exercise of stock options	5,502			—			—			—			—			5,502
Repurchase of common stock for treasury	(9,495		)	—			—			—			—			(9,495		)
Windfall tax benefits from share-based payment arrangements	6,670			—			—			—			—			6,670
Net cash provided by (used for) financing activities	20,924			456,505			(251,521		)	6,000			—			231,908
	Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
	Chemical			Guarantor			(Less Than			Guarantor
	Corporation			Subsidiaries			100% Owned			Subsidiaries
							Guarantor
							Subsidiary)
Effect of exchange rate changes on cash and cash equivalents	—			—			—			(3,687		)	—			(3,687		)
Net increase (decrease) in cash and cash equivalents	231,761			(4,583		)	89,144			35,845			—			352,167
Cash and cash equivalents at beginning of period	420,948			6,227			—			34,126			—			461,301
Cash and cash equivalents at end of period	$	652,709		$	1,644		$	89,144		$	69,971		$	—		$	813,468
Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2013
	Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
	Chemical			Guarantor			(Less Than			Guarantor
	Corporation			Subsidiaries			100% Owned			Subsidiaries
							Guarantor
							Subsidiary)
Statement of Cash Flows
Cash flows from operating activities
Net income (loss)	$	439,453		$	446,858		$	402,340		$	(1,639	)	$	(847,559	)	$	439,453
Adjustments to reconcile net income (loss) to net cash (used for)
provided by operating activities
Depreciation and amortization	1,094			59,893			54,539			1,861			—			117,387
Deferred income taxes	(1,102		)	57,279			27,253			13			—			83,443
Net changes in working capital and other	(458,336		)	(421,066		)	(68,604		)	7,664			847,559			(92,783		)
Net cash (used for) provided by operating activities	(18,891		)	142,964			415,528			7,899			—			547,500
Cash flows from investing activities
Acquisition of business	—			(178,309		)	—			—			—			(178,309		)
Additions to equity investments	—			(23,338		)	—			—			—			(23,338		)
Additions to property, plant and equipment	—			(337,158		)	(158,869		)	(2,263		)	—			(498,290		)
Construction of assets pending sale-leaseback	—			(136		)	—			—			—			(136		)
Proceeds from disposition of assets	—			6			—			72			—			78
Proceeds from repayment of loan to affiliate	—			—			—			167			—			167
Proceeds from sales and maturities of securities	239,764			—			—			—			—			239,764
Purchase of securities	(232,286		)	—			—			—			—			(232,286		)
Settlements of derivative instruments	—			—			(2,297		)	—			—			(2,297		)
Net cash provided by (used for) investing activities	7,478			(538,935		)	(161,166		)	(2,024		)	—			(694,647		)
Cash flows from financing activities
Intercompany financing	(130,832		)	(28,499		)	167,629			(8,298		)	—			—
Net distributions prior to WLKP initial public offering	—			421,991			(421,991		)	—			—			—
Dividends paid	(40,204		)	—			—			—			—			(40,204		)
Proceeds from exercise of stock options	3,182			—			—			—			—			3,182
Repurchase of common stock for treasury	(19,409		)	—			—			—			—			(19,409		)
Windfall tax benefits from share-based payment arrangements	5,056			—			—			—			—			5,056
Net cash (used for) provided by financing activities	(182,207		)	393,492			(254,362		)	(8,298		)	—			(51,375		)
	Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
	Chemical			Guarantor			(Less Than			Guarantor
	Corporation			Subsidiaries			100% Owned			Subsidiaries
							Guarantor
							Subsidiary)
Net decrease in cash and cash equivalents	(193,620		)	(2,479		)	—			(2,423		)	—			(198,522		)
Cash and cash equivalents at beginning of period	753,881			6,973			—			29,224			—			790,078
Cash and cash equivalents at end of period	$	560,261		$	4,494		$	—		$	26,801		$	—		$	591,556

Basis_of_Financial_Statements_

Basis of Financial Statements (Policies)	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of Financial Statements	'
	Basis of Financial Statements
	The accompanying unaudited consolidated interim financial statements were prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the "SEC") for interim periods. Accordingly, certain information and footnotes required for complete financial statements under generally accepted accounting principles in the United States ("U.S. GAAP") have not been included. These interim consolidated financial statements should be read in conjunction with the December 31, 2013 financial statements and notes thereto of Westlake Chemical Corporation (the "Company") included in the annual report on Form 10-K for the fiscal year ended December 31, 2013 (the "2013 Form 10-K"), filed with the SEC on February 21, 2014. These financial statements have been prepared in conformity with the accounting principles and practices as disclosed in the notes to the consolidated financial statements of the Company for the fiscal year ended December 31, 2013.
	In the opinion of the Company's management, the accompanying unaudited consolidated interim financial statements reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair statement of the Company's financial position as of September 30, 2014, its results of operations for the three and nine months ended September 30, 2014 and 2013 and the changes in its cash position for the nine months ended September 30, 2014 and 2013.
	Results of operations and changes in cash position for the interim periods presented are not necessarily indicative of the results that will be realized for the fiscal year ending December 31, 2014 or any other interim period. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.
	On February 14, 2014, the Company's Board of Directors authorized a two-for-one split of the Company's common stock. Stockholders of record as of February 28, 2014 were entitled to one additional share for every share outstanding, which was distributed on March 18, 2014. The total number of authorized common stock shares and associated par value were unchanged by this stock split. All share amounts and per share data included in the accompanying consolidated financial statements and related notes have been restated to reflect the effect of the stock split.
	In March 2014, the Company formed Westlake Chemical Partners LP ("WLKP") to operate, acquire and develop ethylene production facilities and related assets. On August 4, 2014, WLKP closed its initial public offering of 12,937,500 common units. See Note 19 for additional information. The Company consolidates WLKP and records a noncontrolling interest for the interest in WLKP not owned by the Company.
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	Revenue from Contracts with Customers
	In May 2014, the Financial Accounting Standards Board ("FASB") issued an accounting standards update on a comprehensive new revenue recognition standard that will supersede the existing revenue recognition guidance. The new accounting guidance creates a framework by which an entity will allocate the transaction price to separate performance obligations and recognize revenue when each performance obligation is satisfied. Under the new standard, entities will be required to use judgment and make estimates, including identifying performance obligations in a contract, estimating the amount of variable consideration to include in the transaction price, allocating the transaction price to each separate performance obligation and determining when an entity satisfies its performance obligations. The standard allows for either "full retrospective" adoption, meaning that the standard is applied to all of the periods presented with a cumulative catch-up as of the earliest period presented, or "modified retrospective" adoption, meaning the standard is applied only to the most current period presented in the financial statements with a cumulative catch-up as of the current period. The accounting standard will be effective for reporting periods beginning after December 15, 2016. The Company is in the process of evaluating the impact that the new accounting guidance will have on its consolidated financial position, results of operations and cash flows.
	Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern
	In August 2014, the FASB issued an accounting standards update on management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern. The new accounting guidance requires management to perform interim and annual assessments of an entity's ability to continue as a going concern within one year of the date the financial statements are issued. An entity must provide certain disclosures if "conditions or events raise substantial doubt about the entity's ability to continue as a going concern." The accounting standard will be effective for reporting periods ending after December 15, 2016 and is not expected to have an impact on the Company's consolidated financial position, results of operations and cash flows.

Financial_Instruments_Tables

Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2014												Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]	'												'
Marketable Securities	'												'
													Investments in available-for-sale securities were classified as follows:
														September 30,		December 31,
														2014		2013
													Current	$	—	$	239,388
													Non-current	21,066		—
													Total available-for-sale securities	$	21,066	$	239,388
Available-for-sale Securities	'												'
	The cost, gross unrealized gains, gross unrealized losses and fair value of the Company’s available-for-sale securities were as follows:
			September 30, 2014
			Cost			Gross		Gross			Fair Value
						Unrealized		Unrealized
						Gains		Losses
	Equity securities		$	15,044		$	6,022	$	—		$	21,066
	Total available-for-sale securities		$	15,044		$	6,022	$	—		$	21,066
			December 31, 2013
			Cost			Gross		Gross			Fair Value
						Unrealized		Unrealized
						Gains		Losses (1)
	Debt securities
	Corporate bonds		$	108,300		$	340	$	(69	)	$	108,571
	U.S. government debt (2)		106,335			60		(79		)	106,316
	Asset-backed securities		24,478			34		(11		)	24,501
	Total available-for-sale securities		$	239,113		$	434	$	(159	)	$	239,388
	_____________
	-1	All unrealized loss positions were held at a loss for less than 12 months.
	-2	U.S. Treasury obligations, U.S. government agency obligations and U.S government agency mortgage-backed securities.
Schedule of Realized Gain (Loss)	'												'
			Nine Months Ended September 30,
			2014
	Proceeds from sales and maturities of securities		$	342,045
	Gross realized gains		$	1,311
	Gross realized losses		$	(99	)

Accounts_Receivable_Tables

Accounts Receivable (Tables)	9 Months Ended
	Sep. 30, 2014
Accounts Receivable, Net [Abstract]	'
Schedule Of Accounts Receivable	'
	Accounts receivable consist of the following:
		September 30,			December 31,
		2014			2013
	Trade customers	$	576,735		$	410,302
	Affiliates	631			315
	Allowance for doubtful accounts	(13,772		)	(11,741		)
		563,594			398,876
	Federal and state taxes	5,374			20,820
	Other	23,996			8,761
	Accounts receivable, net	$	592,964		$	428,457

Inventories_Tables

Inventories (Tables)	9 Months Ended
	Sep. 30, 2014
Inventory Disclosure [Abstract]	'
Schedule Of Inventory	'
	Inventories consist of the following:
		September 30,		December 31,
		2014		2013
	Finished products	$	268,969	$	232,658
	Feedstock, additives and chemicals	166,268		180,646
	Materials and supplies	65,315		58,575
	Inventories	$	500,552	$	471,879

LongTerm_Debt_Tables

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Schedule Of Long-Term Debt	'
	Long-term debt consists of the following:
		September 30,		December 31,
		2014		2013
	3.60% senior notes due 2022	$	249,079	$	248,990
	6 ½% senior notes due 2029	100,000		100,000
	6 ¾% senior notes due 2032	250,000		250,000
	6 ½% senior notes due 2035 (the "6 ½% GO Zone Senior Notes Due 2035")	89,000		89,000
	6 ½% senior notes due 2035 (the "6 ½% IKE Zone Senior Notes Due 2035")	65,000		65,000
	Loan related to tax-exempt waste disposal revenue bonds due 2027	10,889		10,889
	Long-term debt, net	$	763,968	$	763,879

Derivative_Instruments_Tables

Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Fair Values of Derivatives Instruments in Consolidated Balance Sheets	'
	The fair values of derivative instruments in the Company's consolidated balance sheets were as follows:
		Derivative Assets
		Balance Sheet Location	Fair Value as of
			September 30,			December 31,
			2014			2013
	Not designated as hedging instruments
	Commodity forward contracts	Accounts receivable, net	$	451		$	296
	Total derivative assets		$	451		$	296
		Derivative Liabilities
		Balance Sheet Location	Fair Value as of
			September 30,			December 31,
			2014			2013
	Not designated as hedging instruments
	Commodity forward contracts	Accrued liabilities	$	6,477		$	176
	Total derivative liabilities		$	6,477		$	176
Impact of Derivatives Instruments Designated as Fair Value Hedges	'
	The following tables reflect the impact of derivative instruments designated as fair value hedges and the related hedged item on the Company's consolidated statements of operations. For the three and nine months ended September 30, 2013, there was no material ineffectiveness with regard to the Company's qualifying fair value hedges.
	Derivatives in Fair Value	Location of Gain (Loss)	Three Months Ended September 30,						Nine Months Ended September 30,
	Hedging Relationships	Recognized in
		Income on Derivative	2014			2013			2014			2013
	Commodity forward contracts	Cost of sales	$	—		$	(232	)	$	—		$	(342	)
	Hedged Items in Fair Value	Location of Gain (Loss)	Three Months Ended September 30,						Nine Months Ended September 30,
	Hedging Relationships	Recognized in
		Income on Hedged Items	2014			2013			2014			2013
	Firm commitment designated	Cost of sales	$	—		$	236		$	—		$	15
	as the hedged item
Impact of Derivative Instruments Not Designated as Fair Value Hedges	'
	The impact of derivative instruments that have not been designated as hedges on the Company's consolidated statements of operations were as follows:
	Derivatives Not Designated as	Location of Gain (Loss)	Three Months Ended September 30,						Nine Months Ended September 30,
	Hedging Instruments	Recognized in
		Income on Derivative	2014			2013			2014			2013
	Commodity forward contracts	Gross profit	$	(6,937	)	$	4,854		$	(7,308	)	$	9,897

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Summary Of Assets And Liabilities Accounted At Fair Value On A Recurring Basis	'
	The following tables summarize, by level within the fair value hierarchy, the Company's assets and liabilities that were accounted for at fair value on a recurring basis:
		30-Sep-14
		Level 1			Level 2			Total
	Derivative instruments
	Risk management assets - Commodity forward contracts	$	428		$	23		$	451
	Risk management liabilities - Commodity forward contracts	(119		)	(6,358		)	(6,477		)
	Available-for-sale marketable securities	21,066			—			21,066
		December 31, 2013
		Level 1			Level 2			Total
	Derivative instruments
	Risk management assets - Commodity forward contracts	$	48		$	248		$	296
	Risk management liabilities - Commodity forward contracts	—			(176		)	(176		)
	Available-for-sale marketable securities	91,595			147,793			239,388
Summary Of Carrying And Fair Values Of Long-Term Debt	'
	The carrying and fair values of the Company's long-term debt are summarized in the table below. The Company's long-term debt instruments are publicly-traded. A market approach, based upon quotes from financial reporting services, is used to measure the fair value of the Company's long-term debt. Because the Company's long-term debt instruments may not be actively traded, the inputs used to measure the fair value of the Company's long-term debt are classified as Level 2 inputs within the fair value hierarchy.
		30-Sep-14						December 31, 2013
		Carrying			Fair			Carrying			Fair
		Value			Value			Value			Value
	3.60% senior notes due 2022	$	249,079		$	247,633		$	248,990		$	236,905
	6 ½% senior notes due 2029	100,000			114,624			100,000			109,490
	6 ¾% senior notes due 2032	250,000			275,313			250,000			265,148
	6 ½% GO Zone Senior Notes Due 2035	89,000			101,855			89,000			94,606
	6 ½% IKE Zone Senior Notes Due 2035	65,000			74,389			65,000			69,094
	Loan related to tax-exempt waste disposal revenue	10,889			10,889			10,889			10,889
	bonds due 2027

Earnings_per_Share_Tables

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Schedule Of Net Income Attributable To Common Stockholders	'
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Net income attributable to Westlake Chemical	$	167,757		$	170,290		$	495,232		$	439,453
	Corporation
	Less:
	Net income attributable to participating securities	(353		)	(587		)	(1,099		)	(1,691		)
	Net income attributable to common shareholders	$	167,404		$	169,703		$	494,133		$	437,762
Reconciliation Of Denominator For Basic And Diluted Earnings Per Share	'
	The following table reconciles the denominator for the basic and diluted earnings per share computations shown in the consolidated statements of operations:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Weighted average common shares—basic (1)	133,299,458			133,257,494			133,199,304			133,256,054
	Plus incremental shares from:
	Assumed exercise of options (1)	546,601			553,614			543,841			550,704
	Weighted average common shares—diluted (1)	133,846,059			133,811,108			133,743,145			133,806,758
	Earnings per common share attributable to
	Westlake Chemical Corporation : (1)
	Basic	$	1.26		$	1.28		$	3.71		$	3.29
	Diluted	$	1.25		$	1.27		$	3.69		$	3.27

Pension_and_PostRetirement_Ben1

Pension and Post-Retirement Benefit Costs (Tables)	9 Months Ended
	Sep. 30, 2014
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]	'
Components of Net Periodic Benefit Cost	'
	Components of net periodic benefit cost are as follows:
		Three Months Ended September 30,										Nine Months Ended September 30,
		Pension						Post-retirement				Pension						Post-retirement
								Healthcare										Healthcare
		2014			2013			2014		2013		2014			2013			2014		2013
	Service cost	$	331		$	275		$	6	$	2	$	498		$	815		$	16	$	7
	Interest cost	1,138			515			185		147		2,309			1,531			548		442
	Expected return on	(777		)	(713		)	—		—		(2,363		)	(2,140		)	—		—
	plan assets
	Amortization of prior	74			74			13		21		223			223			38		63
	service cost
	Amortization of net loss	71			510			82		90		204			1,449			220		269
	Net periodic benefit cost	$	837		$	661		$	286	$	260	$	871		$	1,878		$	822	$	781

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	'
	Changes in accumulated other comprehensive income (loss) by component for the nine months ended September 30, 2014 and 2013 were as follows:
			Benefits				Cumulative				Net Unrealized				Total
			Liability,				Foreign				Holding Gains
			Net of Tax				Currency				on Investments,
							Exchange				Net of Tax
	Balances at December 31, 2013		$	(6,696	)		$	3,904			$	176			$	(2,616	)
	Other comprehensive (loss) income before		(39		)		(37,882		)		4,459				(33,462		)
	reclassifications
	Amounts reclassified from accumulated other		422				—				(777		)		(355		)
	comprehensive loss
	Net other comprehensive income (loss) for the period		383				(37,882		)		3,682				(33,817		)
	Balances at September 30, 2014		$	(6,313	)		$	(33,978	)		$	3,858			$	(36,433	)
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	'
	The following table provides the details of the amounts reclassified from accumulated other comprehensive income (loss) into net income in the consolidated statements of operations for the three and nine months ended September 30, 2014 and 2013:
	Details about Accumulated Other Comprehensive		Location of Reclassification		Three Months Ended September 30,								Nine Months Ended September 30,
	Income (Loss) Components		(Income (Expense)) in
			Consolidated Statements
			of Operations		2014				2013				2014				2013
	Amortization of pension and
	other post-retirement items
	Prior service costs		-1		$	(87	)		$	(95	)		$	(261	)		$	(286	)
	Net loss		-1		(153		)		(600		)		(424		)		(1,718		)
					(240		)		(695		)		(685		)		(2,004		)
			Provision for income		92				267				263				771
			taxes
					(148		)		(428		)		(422		)		(1,233		)
	Net unrealized gains on
	available-for-sale
	investments
	Realized gain on		Other income, net		—				—				1,212				—
	available-for-sale
	investments
			Provision for income		—				—				(435		)		—
			taxes
					—				—				$	777			$	—
	Total reclassifications for				$	(148	)		$	(428	)		$	355			$	(1,233	)
	the period
	_____________
	-1	These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. For additional information, please read Note 10 (Employee Benefits) to the financial statements included in the 2013 Form 10-K.

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Segment Reporting Information	'
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Net external sales
	Olefins
	Polyethylene	$	498,450		$	460,105		$	1,461,097		$	1,294,566
	Styrene, feedstock and other	204,647			219,234			663,851			590,959
	Total Olefins	703,097			679,339			2,124,948			1,885,525
	Vinyls
	PVC, caustic soda and other	416,771			212,041			776,060			612,391
	Building products	133,359			112,785			378,471			309,943
	Total Vinyls	550,130			324,826			1,154,531			922,334
		$	1,253,227		$	1,004,165		$	3,279,479		$	2,807,859
	Intersegment sales
	Olefins	$	26,518		$	85,454		$	118,153		$	230,607
	Vinyls	355			403			1,029			1,111
		$	26,873		$	85,857		$	119,182		$	231,718
	Income (loss) from operations
	Olefins	$	259,277		$	237,239		$	770,267		$	585,958
	Vinyls	59,445			39,554			76,460			136,123
	Corporate and other	(11,961		)	(10,191		)	(25,123		)	(26,197		)
		$	306,761		$	266,602		$	821,604		$	695,884
	Depreciation and amortization
	Olefins	$	26,443		$	26,515		$	79,811		$	76,415
	Vinyls	27,336			14,089			68,127			39,507
	Corporate and other	141			124			456			372
		$	53,920		$	40,728		$	148,394		$	116,294
	Other income (expense), net
	Olefins	$	1,609		$	728		$	4,262		$	5,889
	Vinyls	1,189			(742		)	942			(1,687		)
	Corporate and other	(5,468		)	(273		)	(764		)	(1,065		)
		$	(2,670	)	$	(287	)	$	4,440		$	3,137
	Provision for (benefit from) income taxes
	Olefins	$	105,030		$	82,553		$	282,082		$	208,170
	Vinyls	21,761			10,710			22,121			44,120
	Corporate and other	(2,342		)	(535		)	(3,972		)	(7,643		)
		$	124,449		$	92,728		$	300,231		$	244,647
	Capital expenditures
	Olefins	$	48,519		$	27,577		$	121,041		$	105,656
	Vinyls	44,067			172,565			187,449			391,864
	Corporate and other	1,685			276			2,693			770
		$	94,271		$	200,418		$	311,183		$	498,290
Reconciliation Of Total Segment Income From Operations To Consolidated Income Before Income Taxes	'
	A reconciliation of total segment income from operations to consolidated income before income taxes is as follows:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Income from operations	$	306,761		$	266,602		$	821,604		$	695,884
	Interest expense	(9,486		)	(3,297		)	(28,182		)	(14,921		)
	Other (expense) income, net	(2,670		)	(287		)	4,440			3,137
	Income before income taxes	$	294,605		$	263,018		$	797,862		$	684,100
Total Assets	'
		September 30,			December 31,
		2014			2013
	Total assets
	Olefins	$	1,740,878		$	1,557,510
	Vinyls	2,898,250			1,740,595
	Corporate and other	487,155			762,804
		$	5,126,283		$	4,060,909

Westlake_Chemical_Partners_LP_

Westlake Chemical Partners LP (Tables)	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Reconciliation Of Proceeds From Initial Public Offering [Table Text Block]	'
	The following table is a reconciliation of proceeds from the initial public offering:
	Total proceeds from the initial public offering	$	310,500
	Less: Offering Costs	(24,412		)
	Net proceeds from the initial public offering	286,088
	Less: Cash retained by OpCo	(55,419		)
	Net proceeds distributed to the Company from the initial public offering	$	230,669

Acquisitions_Tables

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Business Acquisition, Pro Forma Information	'
	The following unaudited consolidated pro forma information presents consolidated information as if the acquisition had occurred on January 1, 2013:
			Pro Forma
			Nine Months Ended
			September 30,
			2014			2013
	Net sales		$	4,016,935		$	3,747,619
	Net income		$	550,667		$	480,964
	Net income attributable to noncontrolling interests		2,399			—
	Net income attributable to Westlake Chemical Corporation		$	548,268		$	480,964
	Earnings per common share attributable to Westlake Chemical Corporation:
	Basic		$	4.11		$	3.59
	Diluted		$	4.09		$	3.58
	The pro forma amounts above have been calculated after applying the Company’s accounting policies and adjusting the Vinnolit results to reflect (1) the additional depreciation and amortization that would have been charged assuming the fair value adjustments to property, plant and equipment and intangible assets had been applied from January 1, 2013; (2) the elimination of interest expense assuming the long-term debt paid off on behalf of the Sellers as of the acquisition date had been retired as of January 1, 2013; (3) the elimination of transaction-related costs; and (4) an adjustment to tax-effect the aforementioned pro forma adjustments using an estimated aggregate statutory income tax rate of the jurisdictions to which the above adjustments relate. The pro forma amounts do not include any potential synergies, cost savings or other expected benefits of the Vinnolit acquisition, are presented for illustrative purposes only and are not necessarily indicative of results that would have been achieved if the acquisition had occurred as of January 1, 2013 or of future operating performance.
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	'
	The following table summarizes the purchase consideration transferred and the estimated fair value of identified assets acquired and liabilities assumed at the date of acquisition. The preliminary allocation of the purchase consideration is based on management’s estimates, judgments and assumptions. These estimates, judgments and assumptions are subject to change upon final valuation and should be treated as preliminary values. Management estimated that the fair value of the net assets acquired equals consideration paid. Therefore, no goodwill was recorded. The final allocation of purchase consideration could include changes in the estimated fair value of (1) inventories; (2) property, plant and equipment; (3) equity investments; (4) trademark and trade name, developed technologies and customer relationships; (5) power purchase agreement liability; and (6) deferred income taxes.
	Fair value of consideration transferred:
	Cash paid to Sellers		$	309,619
	Cash deposited in escrow (1)		13,390
	Retirement of long-term debt as of July 31, 2014, on behalf of the Sellers (2)		413,215
	Total purchase consideration		$	736,224
	Preliminary allocation of consideration transferred to net assets acquired:
	Cash		$	125,137
	Working capital, excluding inventory and cash (3)		23,072
	Inventories (4)		114,961
	Property, plant and equipment		471,123
	Investments		51,552
	Other assets (5)		65,366
	Intangible assets:
	Trademarks and trade name (weighted average life of 20 years)		40,170
	Developed technologies (weighted average life of 20 years)		31,600
	Other intangibles (weighted average life of 9.4 years)		1,422
	Deferred income tax asset - current		8,697
	Deferred income tax asset - non-current		27,387
	Pension obligation		(117,970		)
	Other long-term liabilities		(10,723		)
	Power purchase agreement liability (6)		(10,826		)
	Deferred income tax liability - current		(6,845		)
	Deferred income tax liability - non-current		(77,899		)
	Total identifiable net assets		736,224
	Goodwill (7)		—
	Consideration transferred		$	736,224
	_____________
	-1	None of the cash held in escrow is considered contingent consideration as it is expected to be released to the Sellers pending the Sellers’ satisfaction of general representations and warranties made in connection with the execution of the purchase agreement.
	-2	Vinnolit’s long-term debt paid on behalf of the Sellers was not legally assumed by Westlake in the acquisition and was a condition of the consummation of the purchase agreement. Therefore, the retirement has been included in the total purchase consideration.
	-3	The fair value of accounts receivable acquired is $181,826, with the gross contractual amount being $183,769. The Company expects $1,943 to be uncollectible.
	-4	An adjustment of approximately $16,900 was recorded to reflect Vinnolit's inventories at fair value and increased cost of sales by the same amount for the three months ended September 30, 2014.
	-5	Included in other assets was a loan acquired that was repaid prior to September 30, 2014.
	-6	A liability arising from unfavorable forward purchase contracts for the purchase of power was recognized at fair value. This liability will be amortized over a period of approximately 3.0 years, being the weighted-average life of the forward purchase contracts.
	-7	Management estimated that the fair value of the net assets acquired equals consideration paid. Therefore, no goodwill was recorded.

Guarantor_Disclosures_Tables

Guarantor Disclosures (Tables)	9 Months Ended
	Sep. 30, 2014
Guarantees [Abstract]	'
Condensed Consolidating Financial Information Balance Sheet	'
	Condensed Consolidating Financial Information as of September 30, 2014
		Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
		Chemical			Guarantor			(Less Than			Guarantor
		Corporation			Subsidiaries			100% Owned			Subsidiaries
								Guarantor
								Subsidiary)
	Balance Sheet
	Current assets
	Cash and cash equivalents	$	652,709		$	1,644		$	89,144		$	69,971		$	—		$	813,468
	Accounts receivable, net	15,064			1,377,250			58,106			170,833			(1,028,289		)	592,964
	Inventories	—			385,826			5,551			109,175			—			500,552
	Prepaid expenses and other current assets	137			14,737			303			3,707			—			18,884
	Deferred income taxes	342			25,446			—			292			—			26,080
	Total current assets	668,252			1,804,903			153,104			353,978			(1,028,289		)	1,951,948
	Property, plant and equipment, net	—			1,451,807			806,648			452,020			—			2,710,475
	Equity investments	3,878,703			1,207,569			—			356,286			(5,371,730		)	70,828
	Other assets, net	34,847			351,271			61,679			137,990			(192,755		)	393,032
	Total assets	$	4,581,802		$	4,815,550		$	1,021,431		$	1,300,274		$	(6,592,774	)	$	5,126,283
	Current liabilities
	Accounts payable	$	979,414		$	157,562		$	29,856		$	100,129		$	(1,003,596	)	$	263,365
	Accrued liabilities	15,448			238,225			3,412			77,279			(24,693		)	309,671
	Total current liabilities	994,862			395,787			33,268			177,408			(1,028,289		)	573,036
	Long-term debt	753,079			10,889			188,523			—			(188,523		)	763,968
	Deferred income taxes	—			473,343			1,507			43,155			(4,232		)	513,773
	Other liabilities	—			31,616			—			121,542			—			153,158
	Total liabilities	1,747,941			911,635			223,298			342,105			(1,221,044		)	2,003,935
	Total Westlake Chemical Corporation stockholders' equity	2,833,861			3,903,915			798,133			669,682			(5,371,730		)	2,833,861
	Noncontrolling interests	—			—			—			288,487			—			288,487
	Total equity	2,833,861			3,903,915			798,133			958,169			(5,371,730		)	3,122,348
	Total liabilities and equity	$	4,581,802		$	4,815,550		$	1,021,431		$	1,300,274		$	(6,592,774	)	$	5,126,283
	Condensed Consolidating Financial Information as of December 31, 2013
		Westlake			100% Owned			OpCo			Non-Guarantor			Eliminations			Consolidated
		Chemical			Guarantor			(Less Than			Subsidiaries
		Corporation			Subsidiaries			100% Owned
								Guarantor
								Subsidiary)
	Balance Sheet
	Current assets
	Cash and cash equivalents	$	420,948		$	6,227		$	—		$	34,126		$	—		$	461,301
	Marketable securities	239,388			—			—			—			—			239,388
	Accounts receivable, net	3,879			666,344			71,812			2,755			(316,333		)	428,457
	Inventories	—			339,929			116,377			15,573			—			471,879
	Prepaid expenses and other current assets	778			11,055			257			1,798			—			13,888
	Deferred income taxes	441			28,974			4,448			306			—			34,169
	Total current assets	665,434			1,052,529			192,894			54,558			(316,333		)	1,649,082
	Property, plant and equipment, net	—			1,318,119			762,972			6,923			—			2,088,014
	Equity investments	2,815,752			636,461			10,411			31,518			(3,427,267		)	66,875
	Other assets, net	15,393			423,901			75,197			1,199			(258,752		)	256,938
	Total assets	$	3,496,579		$	3,431,010		$	1,041,474		$	94,198		$	(4,002,352	)	$	4,060,909
	Current liabilities
	Accounts payable	$	316,652		$	100,570		$	122,564		$	10,649		$	(300,822	)	$	249,613
	Accrued liabilities	8,334			134,452			26,688			1,282			(15,511		)	155,245
	Total current liabilities	324,986			235,022			149,252			11,931			(316,333		)	404,858
	Long-term debt	752,990			10,889			252,973			—			(252,973		)	763,879
	Deferred income taxes	—			260,171			182,855			729			(5,779		)	437,976
	Other liabilities	—			34,571			962			60			—			35,593
	Total equity	2,418,603			2,890,357			455,432			81,478			(3,427,267		)	2,418,603
	Total liabilities and equity	$	3,496,579		$	3,431,010		$	1,041,474		$	94,198		$	(4,002,352	)	$	4,060,909
Condensed Consolidating Financial Information Statement Of Operations	'
	Condensed Consolidating Financial Information for the Three Months Ended September 30, 2014
		Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
		Chemical			Guarantor			(Less Than			Guarantor
		Corporation			Subsidiaries			100% Owned			Subsidiaries
								Guarantor
								Subsidiary)
	Statement of Operations
	Net sales	$	—		$	1,026,282		$	392,008		$	208,313		$	(373,376	)	$	1,253,227
	Cost of sales	—			831,675			227,015			202,110			(369,093		)	891,707
	Gross profit	—			194,607			164,993			6,203			(4,283		)	361,520
	Selling, general and administrative expenses	399			36,445			8,014			14,184			(4,283		)	54,759
	(Loss) income from operations	(399		)	158,162			156,979			(7,981		)	—			306,761
	Interest expense	(10,343		)	(2		)	(2,137		)	(39		)	3,035			(9,486		)
	Other income (expense), net	2,138			(2,942		)	486			683			(3,035		)	(2,670		)
	(Loss) income before income taxes	(8,604		)	155,218			155,328			(7,337		)	—			294,605
	(Benefit from) provision for income taxes	(3,088		)	93,366			36,309			(2,138		)	—			124,449
	Equity in net income of subsidiaries	173,273			113,157			—			5,862			(292,292		)	—
	Net income (loss)	167,757			175,009			119,019			663			(292,292		)	170,156
	Net income attributable to noncontrolling interests	—			—			—			2,399			—			2,399
	Net income (loss) attributable to Westlake Chemical Corporation	$	167,757		$	175,009		$	119,019		$	(1,736	)	$	(292,292	)	$	167,757
	Comprehensive income (loss) attributable to Westlake Chemical	$	131,456		$	175,137		$	119,019		$	(39,528	)	$	(254,628	)	$	131,456
	Corporation
	Condensed Consolidating Financial Information for the Three Months Ended September 30, 2013
		Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
		Chemical			Guarantor			(Less Than			Guarantor
		Corporation			Subsidiaries			100% Owned			Subsidiaries
								Guarantor
								Subsidiary)
	Statement of Operations
	Net sales	$	—		$	844,081		$	540,133		$	13,337		$	(393,386	)	$	1,004,165
	Cost of sales	—			754,037			327,152			11,891			(393,386		)	699,694
	Gross profit	—			90,044			212,981			1,446			—			304,471
	Selling, general and administrative expenses	514			29,323			6,391			1,641			—			37,869
	(Loss) income from operations	(514		)	60,721			206,590			(195		)	—			266,602
	Interest expense	(3,292		)	(5		)	(2,295		)	—			2,295			(3,297		)
	Other income (expense), net	3,585			(2,688		)	1,162			(51		)	(2,295		)	(287		)
	(Loss) income before income taxes	(221		)	58,028			205,457			(246		)	—			263,018
	(Benefit from) provision for income taxes	(70		)	19,973			72,876			(51		)	—			92,728
	Equity in net income of subsidiaries	170,441			132,581			—			—			(303,022		)	—
	Net income (loss) attributable to Westlake Chemical Corporation	$	170,290		$	170,636		$	132,581		$	(195	)	$	(303,022	)	$	170,290
	Comprehensive income attributable to Westlake Chemical	$	171,095		$	170,764		$	132,581		$	351		$	(303,696	)	$	171,095
	Corporation
	Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2014
		Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
		Chemical			Guarantor			(Less Than			Guarantor
		Corporation			Subsidiaries			100% Owned			Subsidiaries
								Guarantor
								Subsidiary)
	Statement of Operations
	Net sales	$	—		$	2,809,844		$	1,476,157		$	229,183		$	(1,235,705	)	$	3,279,479
	Cost of sales	—			2,476,608			832,304			221,233			(1,205,167		)	2,324,978
	Gross profit	—			333,236			643,853			7,950			(30,538		)	954,501
	Selling, general and administrative expenses	1,474			123,050			21,957			16,954			(30,538		)	132,897
	(Loss) income from operations	(1,474		)	210,186			621,896			(9,004		)	—			821,604
	Interest expense	(29,032		)	(8		)	(9,833		)	(39		)	10,730			(28,182		)
	Other income (expense), net	14,488			(1,729		)	3,135			(724		)	(10,730		)	4,440
	(Loss) income before income taxes	(16,018		)	208,449			615,198			(9,767		)	—			797,862
	(Benefit from) provision for income taxes	(5,686		)	109,920			198,461			(2,464		)	—			300,231
	Equity in net income of subsidiaries	505,564			410,875			—			5,862			(922,301		)	—
	Net income (loss)	495,232			509,404			416,737			(1,441		)	(922,301		)	497,631
	Net income attributable to noncontrolling interests	—			—			—			2,399			—			2,399
	Net income (loss) attributable to Westlake Chemical Corporation	$	495,232		$	509,404		$	416,737		$	(3,840	)	$	(922,301	)	$	495,232
	Comprehensive income (loss) attributable to Westlake Chemical	$	461,415		$	509,787		$	416,737		$	(41,722	)	$	(884,802	)	$	461,415
Corporation
Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2013
	Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
	Chemical			Guarantor			(Less Than			Guarantor
	Corporation			Subsidiaries			100% Owned			Subsidiaries
							Guarantor
							Subsidiary)
Statement of Operations
Net sales	$	—		$	2,407,341		$	1,565,809		$	37,561		$	(1,202,852	)	$	2,807,859
Cost of sales	—			2,247,338			924,663			32,943			(1,202,852		)	2,002,092
Gross profit	—			160,003			641,146			4,618			—			805,767
Selling, general and administrative expenses	1,576			84,152			19,326			4,829			—			109,883
(Loss) income from operations	(1,576		)	75,851			621,820			(211		)	—			695,884
Interest expense	(14,882		)	(39		)	(4,893		)	—			4,893			(14,921		)
Other income (expense), net	7,490			(4,002		)	6,422			(1,880		)	(4,893		)	3,137
(Loss) income before income taxes	(8,968		)	71,810			623,349			(2,091		)	—			684,100
(Benefit from) provision for income taxes	(3,202		)	27,292			221,009			(452		)	—			244,647
Equity in net income of subsidiaries	445,219			402,340			—			—			(847,559		)	—
Net income (loss) attributable to Westlake Chemical Corporation	$	439,453		$	446,858		$	402,340		$	(1,639	)	$	(847,559	)	$	439,453
Comprehensive income (loss) attributable to Westlake Chemical	$	439,372		$	447,490		$	402,340		$	(2,483	)	$	(847,347	)	$	439,372
Corporation
Condensed Consolidating Financial Information Statement Of Cash Flows	'
	Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2014
		Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
		Chemical			Guarantor			(Less Than			Guarantor
		Corporation			Subsidiaries			100% Owned			Subsidiaries
								Guarantor
								Subsidiary)
	Statement of Cash Flows
	Cash flows from operating activities
	Net income (loss)	$	495,232		$	509,404		$	416,737		$	(1,441	)	$	(922,301	)	$	497,631
	Adjustments to reconcile net income (loss) to net cash (used for)
	provided by operating activities
	Depreciation and amortization	1,172			82,597			58,501			7,296			—			149,566
	Deferred income taxes	(418		)	26,991			8,267			(381		)	—			34,459
	Net changes in working capital and other	(509,862		)	(919,521		)	1,641			599,909			922,301			94,468
	Net cash (used for) provided by operating activities	(13,876		)	(300,529		)	485,146			605,383			—			776,124
	Cash flows from investing activities
	Acquisition of business, net of cash acquired	—			—			—			(611,087		)	—			(611,087		)
	Additions to property, plant and equipment	—			(160,147		)	(144,348		)	(6,688		)	—			(311,183		)
	Proceeds from disposition of assets	—			144			—			1			—			145
	Proceeds from repayment of loan acquired	—			—			—			45,923			—			45,923
	Proceeds from sales and maturities of securities	342,045			—			—			—			—			342,045
	Purchase of securities	(117,332		)	—			—			—			—			(117,332		)
	Settlements of derivative instruments	—			(556		)	(133		)	—			—			(689		)
	Net cash provided by (used for) investing activities	224,713			(160,559		)	(144,481		)	(571,851		)	—			(652,178		)
	Cash flows from financing activities
	Intercompany financing	75,104			(143,325		)	62,221			6,000			—			—
	Net distributions prior to WLKP initial public offering	—			448,101			(448,101		)	—			—			—
	Capitalized debt issuance costs	(1,167		)	—			—			—			—			(1,167		)
	Dividends paid	(55,690		)	151,729			(151,729		)	—			—			(55,690		)
	Net proceeds from issuance of WLKP common units	—			—			—			286,088			—			286,088
	Purchase of limited partner interests	—			—			286,088			(286,088		)	—			—
	Proceeds from exercise of stock options	5,502			—			—			—			—			5,502
	Repurchase of common stock for treasury	(9,495		)	—			—			—			—			(9,495		)
	Windfall tax benefits from share-based payment arrangements	6,670			—			—			—			—			6,670
	Net cash provided by (used for) financing activities	20,924			456,505			(251,521		)	6,000			—			231,908
		Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
		Chemical			Guarantor			(Less Than			Guarantor
		Corporation			Subsidiaries			100% Owned			Subsidiaries
								Guarantor
								Subsidiary)
	Effect of exchange rate changes on cash and cash equivalents	—			—			—			(3,687		)	—			(3,687		)
	Net increase (decrease) in cash and cash equivalents	231,761			(4,583		)	89,144			35,845			—			352,167
	Cash and cash equivalents at beginning of period	420,948			6,227			—			34,126			—			461,301
	Cash and cash equivalents at end of period	$	652,709		$	1,644		$	89,144		$	69,971		$	—		$	813,468
	Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2013
		Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
		Chemical			Guarantor			(Less Than			Guarantor
		Corporation			Subsidiaries			100% Owned			Subsidiaries
								Guarantor
								Subsidiary)
	Statement of Cash Flows
	Cash flows from operating activities
	Net income (loss)	$	439,453		$	446,858		$	402,340		$	(1,639	)	$	(847,559	)	$	439,453
	Adjustments to reconcile net income (loss) to net cash (used for)
	provided by operating activities
	Depreciation and amortization	1,094			59,893			54,539			1,861			—			117,387
	Deferred income taxes	(1,102		)	57,279			27,253			13			—			83,443
	Net changes in working capital and other	(458,336		)	(421,066		)	(68,604		)	7,664			847,559			(92,783		)
	Net cash (used for) provided by operating activities	(18,891		)	142,964			415,528			7,899			—			547,500
	Cash flows from investing activities
	Acquisition of business	—			(178,309		)	—			—			—			(178,309		)
	Additions to equity investments	—			(23,338		)	—			—			—			(23,338		)
	Additions to property, plant and equipment	—			(337,158		)	(158,869		)	(2,263		)	—			(498,290		)
Construction of assets pending sale-leaseback	—			(136		)	—			—			—			(136		)
Proceeds from disposition of assets	—			6			—			72			—			78
Proceeds from repayment of loan to affiliate	—			—			—			167			—			167
Proceeds from sales and maturities of securities	239,764			—			—			—			—			239,764
Purchase of securities	(232,286		)	—			—			—			—			(232,286		)
Settlements of derivative instruments	—			—			(2,297		)	—			—			(2,297		)
Net cash provided by (used for) investing activities	7,478			(538,935		)	(161,166		)	(2,024		)	—			(694,647		)
Cash flows from financing activities
Intercompany financing	(130,832		)	(28,499		)	167,629			(8,298		)	—			—
Net distributions prior to WLKP initial public offering	—			421,991			(421,991		)	—			—			—
Dividends paid	(40,204		)	—			—			—			—			(40,204		)
Proceeds from exercise of stock options	3,182			—			—			—			—			3,182
Repurchase of common stock for treasury	(19,409		)	—			—			—			—			(19,409		)
Windfall tax benefits from share-based payment arrangements	5,056			—			—			—			—			5,056
Net cash (used for) provided by financing activities	(182,207		)	393,492			(254,362		)	(8,298		)	—			(51,375		)
	Westlake			100% Owned			OpCo			Non-			Eliminations			Consolidated
	Chemical			Guarantor			(Less Than			Guarantor
	Corporation			Subsidiaries			100% Owned			Subsidiaries
							Guarantor
							Subsidiary)
Net decrease in cash and cash equivalents	(193,620		)	(2,479		)	—			(2,423		)	—			(198,522		)
Cash and cash equivalents at beginning of period	753,881			6,973			—			29,224			—			790,078
Cash and cash equivalents at end of period	$	560,261		$	4,494		$	—		$	26,801		$	—		$	591,556

Basis_of_Financial_Statements_1

Basis of Financial Statements Basis (Details)	0 Months Ended
	Feb. 14, 2014	Aug. 04, 2014
		Limited Partner [Member]
		Subsidiaries [Member]
		Westlake Chemical Partners LP [Member]
		IPO [Member]
Number of units sold in public offering	'	12,937,500
Stock split conversion ratio	2	'

Financial_Instruments_Cash_Equ

Financial Instruments Cash Equivalents (Details) (Held-to-maturity Securities, USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Held-to-maturity Securities	'	'
Cash Equivalents [Line Items]	'	'
Cash Equivalents, at Carrying Value	$747,008	$263,967

Financial_Instruments_Marketab

Financial Instruments Marketable Securities (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]	'	'
Current	$0	$239,388
Noncurrent	21,066	0
Total Available-for-sale Securities	$21,066	$239,388

Financial_Instruments_Availabl

Financial Instruments Available-for-sale Securities (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	$15,044	$239,113
GrossUnrealizedGain	6,022	434
GrossUnrealizedLoss	0	-159
Fair Value	-21,066	-239,388
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax	3,858	176
Available-for-sale Securities, Income Tax Expense on Change in Unrealized Holding Gain (Loss)	2,164	99
Proceeds from Sale of Available-for-sale Securities	342,045	'
Gross Realized Gains	1,311	'
Gross Realized Losses	-99	'
Corporate bonds	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	'	108,300
GrossUnrealizedGain	'	340
GrossUnrealizedLoss	'	-69
Fair Value	'	-108,571
U.S. government debt	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	'	106,335
GrossUnrealizedGain	'	60
GrossUnrealizedLoss	'	-79
Fair Value	'	-106,316
Asset-backed securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	'	24,478
GrossUnrealizedGain	'	34
GrossUnrealizedLoss	'	-11
Fair Value	'	-24,501
Equity Securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	15,044	'
GrossUnrealizedGain	6,022	'
GrossUnrealizedLoss	0	'
Fair Value	($21,066)	'

Accounts_Receivable_Details

Accounts Receivable (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accounts Receivable, Net [Abstract]	'	'
Trade customers	$576,735	$410,302
Affiliates	631	315
Allowance for doubtful accounts	-13,772	-11,741
Receivables from trade customers and affiliates, net	563,594	398,876
Federal and state taxes	5,374	20,820
Other	23,996	8,761
Accounts receivable, net	$592,964	$428,457

Inventories_Details

Inventories (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]	'	'
Finished products	$268,969	$232,658
Feedstock, additives and chemicals	166,268	180,646
Materials and supplies	65,315	58,575
Inventories	$500,552	$471,879

Property_Plant_and_Equipment_D

Property, Plant and Equipment (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'	'	'	'	'
Property, plant and equipment	$2,710,475	'	$2,710,475	'	$2,088,014
Depreciation expense on property, plant and equipment	$45,080	$32,460	$123,000	$95,995	'

Other_Assets_Additional_Inform

Other Assets (Additional Information) (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Other Assets [Line Items]	'	'	'	'
Amortization expense on intangible assets, included in other assets	$9,283	$8,634	$26,566	$21,392
Olefins	'	'	'	'
Other Assets [Line Items]	'	'	'	'
Goodwill	29,990	'	29,990	'
Vinyls	'	'	'	'
Other Assets [Line Items]	'	'	'	'
Goodwill	$32,026	'	$32,026	'

LongTerm_Debt_Schedule_of_Long

Long-Term Debt (Schedule of Long-term Debt) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Debt Instrument [Line Items]	'	'
Long-term debt	$763,968	$763,879
3.60% Senior Notes Due 2022	'	'
Debt Instrument [Line Items]	'	'
Maturity	'2022	'
Stated interest rate	3.60%	'
Senior notes	249,079	248,990
6 1/2% Senior Notes Due 2029	'	'
Debt Instrument [Line Items]	'	'
Maturity	'2029	'
Stated interest rate	6.50%	'
Senior notes	100,000	100,000
6 3/4% Senior Notes Due 2032	'	'
Debt Instrument [Line Items]	'	'
Maturity	'2032	'
Stated interest rate	6.75%	'
Senior notes	250,000	250,000
2035 GO Zone 6 1/2% Notes	'	'
Debt Instrument [Line Items]	'	'
Maturity	'2035	'
Stated interest rate	6.50%	'
Senior notes	89,000	89,000
2035 IKE Zone 6 1/2% Notes	'	'
Debt Instrument [Line Items]	'	'
Maturity	'2035	'
Stated interest rate	6.50%	'
Senior notes	65,000	65,000
Loan Related To Tax-Exempt Waste Disposal Revenue Bonds Due 2027	'	'
Debt Instrument [Line Items]	'	'
Maturity	'2027	'
Non-current loan payable	$10,889	$10,889

LongTerm_Debt_Revolving_Credit

Long-Term Debt (Revolving Credit Facility) (Details) (Line of Credit, USD $)	3 Months Ended
	Sep. 30, 2014
Line of Credit Facility [Line Items]	'
Maximum borrowing capacity	$400,000,000
Long-term Line of Credit	0
Percentage of commitment on borrowing availability	0.25%
Letters of credit outstanding	32,399,000
Remaining borrowing capacity	367,601,000
Revolving Credit Facility, Covenant Terms	'
Covenant terms, distributions restrictions, borrowing availability threshold, percent of commitments, option 1	20.00%
Covenant terms, distributions restrictions, borrowing availability threshold, option 1	80,000,000
Covenant terms, distributions restrictions, borrowing availability threshold, percent of commitments, option 2	15.00%
Covenant terms, distributions restrictions, borrowing availability threshold, option 2	60,000,000
Covenant terms, distributions restrictions, fixed coverage ratio, option 2	100.00%
Covenant terms, acquisitions and investments, borrowing availability threshold, percent of commitments, option 1	15.00%
Covenant terms, acquisitions and investments, borrowing availability threshold, option 2	50,000,000
Covenant terms, acquisitions and investments, borrowing availability threshold, percent of commitments, option 2	12.50%
Covenant terms, acquisitions and investments restrictions, fixed coverage ration, option 2	100.00%
Covenant terms, specified investments permissible	50,000,000
Covenant terms, specified investments permissible, percentage of tangible assets and acquisitions	1.25%
Covenant terms, specified acquisitions permissible	100,000,000
Covenant terms, specified acquisitions permissible, percentage of tangible assets	2.50%
Covenant terms, acquisitions restrictions, borrowing availability threshold, percent of commitments, option 2	100.00%
Minimum	'
Line of Credit Facility [Line Items]	'
Increase in credit facility borrowings	25,000,000
Revolving Credit Facility, Covenant Terms	'
Covenant terms, acquisitions restrictions, borrowing availability threshold, percent of commitments, option 1	12.50%
Covenant terms, acquisitions restrictions, borrowing availability threshold, option 1	50,000,000
Maximum	'
Line of Credit Facility [Line Items]	'
Increase in credit facility borrowings	200,000,000
Revolving Credit Facility, Covenant Terms	'
Covenant terms, specified distributions permissible	75,000,000
Covenant terms, specified distributions permissible, annual increase, percentage	5.00%
Covenant terms, acquisitions restrictions, borrowing availability threshold, percent of commitments, option 1	15.00%
Covenant terms, acquisitions restrictions, borrowing availability threshold, option 1	60,000,000
LIBOR [Member]	'
Line of Credit Facility [Line Items]	'
Maximum basis spread, provided company is rated investment grade	1.50%
Revolving Credit Facility, Covenant Terms	'
Covenant terms, acquisitions and investments, borrowing availability threshold, option 1	$60,000,000
LIBOR [Member] | Minimum	'
Line of Credit Facility [Line Items]	'
Percentage added to basis to find interest rate	1.25%
LIBOR [Member] | Maximum	'
Line of Credit Facility [Line Items]	'
Percentage added to basis to find interest rate	1.75%
Base Rate [Member] | Minimum	'
Line of Credit Facility [Line Items]	'
Percentage added to basis to find interest rate	0.00%
Base Rate [Member] | Maximum	'
Line of Credit Facility [Line Items]	'
Percentage added to basis to find interest rate	0.50%

StockBased_Compensation_Detail

Stock-Based Compensation (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'	'
Stock-based compensation expense	$2,346	$1,680	$6,856	$4,804

Derivative_Instruments_Textual

Derivative Instruments (Textual) (Detail) (Commodity Forward Contracts [Member], Designated As Fair Value Hedges)	Sep. 30, 2014
	instrument
Commodity Forward Contracts [Member] | Designated As Fair Value Hedges	'
Derivative [Line Items]	'
Number of derivative instruments	0

Derivative_Instruments_Fair_Va

Derivative Instruments (Fair Values of Derivative Instruments in Consolidated Balance Sheets) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accrued Liabilities	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative liabilities	$6,477	$176
Accounts Receivable	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative assets	451	296
Forward Contracts [Member] | Accrued Liabilities	'	'
Derivatives, Fair Value [Line Items]	'	'
Not designated as hedging instruments, Derivative Liabilities	6,477	176
Forward Contracts [Member] | Accounts Receivable	'	'
Derivatives, Fair Value [Line Items]	'	'
Not designated as hedging instruments, Derivative Assets	$451	$296

Derivative_Instruments_Impact_

Derivative Instruments (Impact of Derivative Instruments on Income) (Details) (Cost of Sales, USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Designated As Fair Value Hedges | Firm Commitment Derivative Items Designated As Hedged Item	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Gain (Loss) Recognized in Income on Derivative	$0	$236	$0	$15
Designated As Fair Value Hedges | Forward Contracts [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Gain (Loss) Recognized in Income on Derivative	0	-232	0	-342
Derivatives Not Designated As Hedging Instruments | Forward Contracts [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Gain (Loss) Recognized in Income on Derivative	($6,937)	$4,854	($7,308)	$9,897

Fair_Value_Measurements_Summar

Fair Value Measurements (Summary of Assets and Liabilities Accounted at Fair Value on Recurring Basis) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available for Sale	$0	$239,388
Recurring	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available for Sale	21,066	239,388
Recurring | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available for Sale	21,066	91,595
Recurring | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available for Sale	0	147,793
Recurring | Forward Contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Risk management assets - Commodity forward contracts	451	296
Risk management liabilities - Commodity forward contracts	-6,477	-176
Recurring | Forward Contracts [Member] | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Risk management assets - Commodity forward contracts	428	48
Risk management liabilities - Commodity forward contracts	-119	0
Recurring | Forward Contracts [Member] | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Risk management assets - Commodity forward contracts	23	248
Risk management liabilities - Commodity forward contracts	($6,358)	($176)

Fair_Value_Measurements_Summar1

Fair Value Measurements (Summary of Carrying and Fair Values of Long Term Debt) (Details) (USD $)

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

In Thousands, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

3.60% Senior Notes Due 2022

3.60% Senior Notes Due 2022

3.60% Senior Notes Due 2022

3.60% Senior Notes Due 2022

3.60% Senior Notes Due 2022

6 1/2% Senior Notes Due 2029

6 1/2% Senior Notes Due 2029

6 1/2% Senior Notes Due 2029

6 1/2% Senior Notes Due 2029

6 1/2% Senior Notes Due 2029

6 3/4% Senior Notes Due 2032

6 3/4% Senior Notes Due 2032

6 3/4% Senior Notes Due 2032

6 3/4% Senior Notes Due 2032

6 3/4% Senior Notes Due 2032

2035 GO Zone 6 1/2% Notes

2035 GO Zone 6 1/2% Notes

2035 GO Zone 6 1/2% Notes

2035 GO Zone 6 1/2% Notes

2035 GO Zone 6 1/2% Notes

2035 IKE Zone 6 1/2% Notes

2035 IKE Zone 6 1/2% Notes

2035 IKE Zone 6 1/2% Notes

2035 IKE Zone 6 1/2% Notes

2035 IKE Zone 6 1/2% Notes

Loan Related To Tax-Exempt Waste Disposal Revenue Bonds Due 2027

Loan Related To Tax-Exempt Waste Disposal Revenue Bonds Due 2027

Loan Related To Tax-Exempt Waste Disposal Revenue Bonds Due 2027

Loan Related To Tax-Exempt Waste Disposal Revenue Bonds Due 2027

Loan Related To Tax-Exempt Waste Disposal Revenue Bonds Due 2027

Carrying Value

Carrying Value

Fair Value

Fair Value

Carrying Value

Carrying Value

Fair Value

Fair Value

Carrying Value

Carrying Value

Fair Value

Fair Value

Carrying Value

Carrying Value

Fair Value

Fair Value

Carrying Value

Carrying Value

Fair Value

Fair Value

Carrying Value

Carrying Value

Fair Value

Fair Value

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maturity

'2022

'

'

'

'

'2029

'

'

'

'

'2032

'

'

'

'

'2035

'

'

'

'

'2035

'

'

'

'

'2027

'

'

'

'

Stated interest rate

3.60%

'

'

'

'

6.50%

'

'

'

'

6.75%

'

'

'

'

6.50%

'

'

'

'

6.50%

'

'

'

'

'

'

'

'

'

Senior notes

'

$249,079

$248,990

$247,633

$236,905

'

$100,000

$100,000

$114,624

$109,490

'

$250,000

$250,000

$275,313

$265,148

'

$89,000

$89,000

$101,855

$94,606

'

$65,000

$65,000

$74,389

$69,094

'

'

'

'

'

Loans

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$10,889

$10,889

$10,889

$10,889

Income_Taxes_Detail

Income Taxes (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'	'
Effective income tax rate	37.60%	35.80%
U.S. federal statutory income tax rate	35.00%	35.00%
Anticipated reductions to unrecognized tax benefits within next twelve months	$2,501	'

Earnings_per_Share_Additional_

Earnings per Share (Additional Information) (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Number of options excluded from computation of diluted earnings per share	0	137,324	0	115,518

Earnings_per_Share_Schedule_of

Earnings per Share (Schedule of Net Income Attributable to Common Stockholders) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Net income to Westlake Chemical Corporation	$167,757	$170,290	$495,232	$439,453
Less: Net income attributable to participating securities	-353	-587	-1,099	-1,691
Net income attributable to common shareholders	$167,404	$169,703	$494,133	$437,762

Earnings_per_Share_Reconciliat

Earnings per Share (Reconciliation of Denominator for Basic and Diluted Earnings Per Share) (Details) (USD $)	0 Months Ended	3 Months Ended				9 Months Ended
	Feb. 14, 2014	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Earnings Per Share [Abstract]	'	'		'		'		'
Basic	'	133,299,458	[1]	133,257,494	[1]	133,199,304	[1]	133,256,054	[1]
Plus incremental shares from: Assumed exercise of options	'	546,601	[1]	553,614	[1]	543,841	[1]	550,704	[1]
Weighted average common shares-diluted	'	133,846,059	[1]	133,811,108	[1]	133,743,145	[1]	133,806,758	[1]
Earnings per share: Basic	'	$1.26	[1]	$1.28	[1]	$3.71	[1]	$3.29	[1]
Earnings per share: Diluted	'	$1.25	[1]	$1.27	[1]	$3.69	[1]	$3.27	[1]
Stock split conversion ratio	2	'		'		'		'
[1]	Share amounts and per share data for the three and nine months ended September 30, 2013 have been restated to reflect the effect of a two-for-one stock split on MarchB 18, 2014. See Note 1 for additional information.

Pension_and_PostRetirement_Ben2

Pension and Post-Retirement Benefit Costs (Components of Net Periodic Benefit Cost) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pension	'	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'	'
Service cost	$331	$275	$498	$815
Interest cost	1,138	515	2,309	1,531
Expected return on plan assets	-777	-713	-2,363	-2,140
Amortization of prior service cost	74	74	223	223
Amortization of net loss	71	510	204	1,449
Net periodic benefit cost	837	661	871	1,878
Post-Retirement Healthcare	'	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'	'
Service cost	6	2	16	7
Interest cost	185	147	548	442
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	13	21	38	63
Amortization of net loss	82	90	220	269
Net periodic benefit cost	$286	$260	$822	$781

Pension_and_PostRetirement_Ben3

Pension and Post-Retirement Benefit Costs (Additional Information) (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Defined Benefit Plan Disclosure [Line Items]	'	'
Document Fiscal Year Focus	'2014	'
Salaried Pension Plan	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Employer contribution	$2,447	$776
Expected additional contributions	330	'
Wage Pension Plan	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Employer contribution	916	640
Expected additional contributions	$290	'

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income Changes in AOCI (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Accumulated other comprehensive income (loss), beginning balance	'	'	($2,616)	($10,840)	($10,840)
Other comprehensive loss before reclassifications	'	'	-33,462	-1,314	'
Amounts reclassified from accumulated other comprehensive loss	'	'	-355	1,233	'
Other comprehensive (loss) income	-36,301	805	-33,817	-81	8,224
Accumulated other comprehensive income (loss), ending balance	-36,433	-10,921	-36,433	-10,921	-2,616
Benefits Liability, Net of Tax	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Accumulated other comprehensive income (loss), beginning balance	'	'	-6,696	-16,351	-16,351
Other comprehensive loss before reclassifications	'	'	-39	-601	'
Amounts reclassified from accumulated other comprehensive loss	'	'	422	1,233	'
Other comprehensive (loss) income	'	'	383	632	'
Accumulated other comprehensive income (loss), ending balance	-6,313	-15,719	-6,313	-15,719	'
Cumulative Foreign Currency Exchange	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Accumulated other comprehensive income (loss), beginning balance	'	'	3,904	5,511	5,511
Other comprehensive loss before reclassifications	'	'	-37,882	-844	'
Amounts reclassified from accumulated other comprehensive loss	'	'	0	0	'
Other comprehensive (loss) income	'	'	-37,882	-844	'
Accumulated other comprehensive income (loss), ending balance	-33,978	4,667	-33,978	4,667	'
Net Unrealized Holding Gains on Investmetnts, Net of Tax	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Accumulated other comprehensive income (loss), beginning balance	'	'	176	0	0
Other comprehensive loss before reclassifications	'	'	4,459	131	'
Amounts reclassified from accumulated other comprehensive loss	'	'	-777	0	'
Other comprehensive (loss) income	'	'	3,682	131	'
Accumulated other comprehensive income (loss), ending balance	$3,858	$131	$3,858	$131	'

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Income Reclassifications in AOCI (Details) (USD $)	3 Months Ended				9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'		'		'
Income before income taxes	$294,605		$263,018		$797,862		$684,100
Realized gain on available-for-sale investments	-2,670		-287		4,440		3,137
Provision for income taxes	-124,449		-92,728		-300,231		-244,647
Net income to Westlake Chemical Corporation	167,757		170,290		495,232		439,453
Reclassification out of Accumulated Other Comprehensive Income	'		'		'		'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'		'		'
Net income to Westlake Chemical Corporation	-148		-428		355		-1,233
Accumulated Defined Benefit Plans Adjustment | Reclassification out of Accumulated Other Comprehensive Income	'		'		'		'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'		'		'
Prior service costs	-87	[1]	-95	[1]	-261	[1]	-286	[2]
Net loss	-153	[1]	-600	[1]	-424	[1]	-1,718	[2]
Income before income taxes	-240		-695		-685		-2,004
Provision for income taxes	92		267		263		771
Net income to Westlake Chemical Corporation	-148		-428		-422		-1,233
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Reclassification out of Accumulated Other Comprehensive Income	'		'		'		'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'		'		'
Realized gain on available-for-sale investments	0		0		1,212		0
Provision for income taxes	0		0		-435		0
Net income to Westlake Chemical Corporation	$0		$0		$777		$0
[1]	These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. For additional information, please read Note 10 (Employee Benefits) to the financial statements included in the 2013 Form 10-K.
[2]	Share amounts and per share data for the three and nine months ended September 30, 2013 have been restated to reflect the effect of a two-for-one stock split on MarchB 18, 2014. See Note 1 for additional information.

Commitments_and_Contingencies_

Commitments and Contingencies (Additional Information) (Detail) (USD $)	0 Months Ended	1 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Mar. 17, 2010	Dec. 31, 2007	Dec. 31, 2007	Dec. 31, 2013
			Polyone	Polyone
Commitments and Contingencies Disclosure [Line Items]	'	'	'	'
Minimum number of years between arbitrations	'	'5 years	'	'
Reimbursement of remediation costs sought by PolyOne	$1,400	'	'	'
Percentage of costs related to environmental issues to be paid by PolyOne	'	'	100.00%	'
Costs incurred environmental remediation services	'	'	'	$3,284

Share_Capital_Details

Share Capital (Details) (USD $)	1 Months Ended
In Thousands, except Share data, unless otherwise specified	Aug. 31, 2011	Sep. 30, 2014	16-May-14	15-May-14	Dec. 31, 2013
Equity [Abstract]	'	'	'	'	'
Common stock, shares authorized	'	300,000,000	300,000,000	150,000,000	150,000,000
Common stock, par value	'	$0.01	$0.01	'	$0.01
Common stock, shares issued	'	134,680,164	'	'	134,580,208
Common stock, held in treasury	'	1,220,544	'	'	1,252,922
Stock repurchase program, authorized amount	$100,000	'	'	'	'
Shares repurchased	'	1,357,085	'	'	1,252,922

Supplemental_Information_Detai

Supplemental Information (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'	'
Other liabilities	$153,158	$35,593
Noncurrent pension obligation	$117,293	$8,710

Segment_Information_Additional

Segment Information (Additional Information) (Detail)	3 Months Ended
	Sep. 30, 2014
	Segment
Segment Reporting [Abstract]	'
Number of segments	2

Segment_Information_Details

Segment Information (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]	'	'	'	'
Net external sales	$1,253,227	$1,004,165	$3,279,479	$2,807,859
Income (loss) from operations	306,761	266,602	821,604	695,884
Depreciation and amortization	53,920	40,728	148,394	116,294
Other (expense) income, net	-2,670	-287	4,440	3,137
Provision for (benefit from) income taxes	124,449	92,728	300,231	244,647
Capital expenditures	94,271	200,418	311,183	498,290
Olefins	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Net external sales	703,097	679,339	2,124,948	1,885,525
Income (loss) from operations	259,277	237,239	770,267	585,958
Depreciation and amortization	26,443	26,515	79,811	76,415
Other (expense) income, net	1,609	728	4,262	5,889
Provision for (benefit from) income taxes	105,030	82,553	282,082	208,170
Capital expenditures	48,519	27,577	121,041	105,656
Vinyls	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Net external sales	550,130	324,826	1,154,531	922,334
Income (loss) from operations	59,445	39,554	76,460	136,123
Depreciation and amortization	27,336	14,089	68,127	39,507
Other (expense) income, net	1,189	-742	942	-1,687
Provision for (benefit from) income taxes	21,761	10,710	22,121	44,120
Capital expenditures	44,067	172,565	187,449	391,864
Corporate and Other	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Income (loss) from operations	-11,961	-10,191	-25,123	-26,197
Depreciation and amortization	141	124	456	372
Other (expense) income, net	-5,468	-273	-764	-1,065
Provision for (benefit from) income taxes	-2,342	-535	-3,972	-7,643
Capital expenditures	1,685	276	2,693	770
Polyethylene | Olefins	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Net external sales	498,450	460,105	1,461,097	1,294,566
Ethylene, Styrene And Other | Olefins	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Net external sales	204,647	219,234	663,851	590,959
PVC, Caustic Soda And Other | Vinyls	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Net external sales	416,771	212,041	776,060	612,391
Building Products | Vinyls	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Net external sales	133,359	112,785	378,471	309,943
Intersegment sales	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Net external sales	26,873	85,857	119,182	231,718
Intersegment sales | Olefins	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Net external sales	26,518	85,454	118,153	230,607
Intersegment sales | Vinyls	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Net external sales	$355	$403	$1,029	$1,111

Segment_Information_Reconcilia

Segment Information (Reconciliation of Total Segment Income from Operations to Consolidated Income before Income Taxes) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting [Abstract]	'	'	'	'
Income from operations	$306,761	$266,602	$821,604	$695,884
Interest expense	-9,486	-3,297	-28,182	-14,921
Other (expense) income, net	-2,670	-287	4,440	3,137
Income before income taxes	$294,605	$263,018	$797,862	$684,100

Segment_Information_Total_Asse

Segment Information (Total Assets) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Segment Reporting, Asset Reconciling Item [Line Items]	'	'
Total assets	$5,126,283	$4,060,909
Olefins	'	'
Segment Reporting, Asset Reconciling Item [Line Items]	'	'
Total assets	1,740,878	1,557,510
Vinyls	'	'
Segment Reporting, Asset Reconciling Item [Line Items]	'	'
Total assets	2,898,250	1,740,595
Corporate and Other	'	'
Segment Reporting, Asset Reconciling Item [Line Items]	'	'
Total assets	$487,155	$762,804

Westlake_Chemical_Partners_LP_1

Westlake Chemical Partners LP (Narrative) (Details) (USD $)	9 Months Ended		0 Months Ended				0 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Aug. 04, 2014	Aug. 04, 2014	Aug. 04, 2014	Aug. 04, 2014	Aug. 04, 2014	Aug. 04, 2014	Aug. 04, 2014	Aug. 04, 2014
			IPO [Member]	Subsidiaries [Member]	Subsidiaries [Member]	Subsidiaries [Member]	Subsidiaries [Member]	Cash Reserve Turnaround [Member]	Preformation Capital Expenditure [Member]	Intercompany Debt [Member]
			Limited Partner [Member]	Westlake Chemical Partners LP [Member]	Westlake Chemical Partners LP [Member]	Westlake Chemical Partners LP [Member]	Westlake Chemical Partners LP [Member]	Subsidiaries [Member]	Subsidiaries [Member]	Subsidiaries [Member]
				IPO [Member]	IPO [Member]	IPO [Member]	Over-Allotment Option [Member]	Westlake Chemical OpCo LP [Member]	Westlake Chemical OpCo LP [Member]	Westlake Chemical OpCo LP [Member]
					Limited Partner [Member]	Limited Partner [Member]	Limited Partner [Member]	IPO [Member]	IPO [Member]	IPO [Member]
Number of units sold in public offering	'	'	'	'	12,937,500	'	1,687,500	'	'	'
Price per unit	'	'	'	'	'	$24	'	'	'	'
Approximate proceeds from sale of units	$286,088	$0	'	'	$286,088	'	'	'	'	'
Estimated offering expenses from sale of partnership units	'	'	'	'	-24,412	'	'	'	'	'
Limited partner interest	'	'	89.40%	'	10.60%	'	'	'	'	'
Percentage sold to public in IPO	'	'	'	47.80%	'	'	'	'	'	'
Amount used from proceeds	'	'	'	'	'	'	'	($55,419)	($151,729)	($78,940)

Westlake_Chemical_Partners_LP_2

Westlake Chemical Partners LP (Reconciliation of Proceeds from IPO) (Details) (USD $)	9 Months Ended		0 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Aug. 04, 2014	Aug. 04, 2014	Aug. 04, 2014
			Westlake Chemical Partners LP [Member]	Limited Partner [Member]	Cash Reserve Turnaround [Member]
			IPO [Member]	Westlake Chemical Partners LP [Member]	Westlake Chemical OpCo LP [Member]
			Subsidiaries [Member]	IPO [Member]	IPO [Member]
				Subsidiaries [Member]	Subsidiaries [Member]
Total proceeds from the initial public offering	'	'	'	$310,500	'
Less: Offering Costs	'	'	'	24,412	'
Net proceeds from issuance of Westlake Chemical Partners LP common units	286,088	0	'	286,088	'
Less: Cash retained by OpCo	'	'	'	'	55,419
Net proceeds distributed to the Company from the initial public offering	'	'	$230,669	'	'

Acquisitions_Narrative_Details

Acquisitions (Narrative) (Details) (Vinnolit [Member], USD $)	0 Months Ended	2 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Sep. 30, 2014	Sep. 30, 2014
Business Acquisition [Line Items]	'	'	'
Purchase price	$736,224	'	'
Net sales contributed by acquired business since acquisition date	'	195,477	'
Net loss contributed by acquired business since acquisition date	'	-2,992	'
Transaction-related costs	'	'	$11,235
PVC Resin Member [Member]	'	'	'
Business Acquisition [Line Items]	'	'	'
Combined annual capacity	1,700,000,000	'	'
Vinyl Chloride Monomer [Member]	'	'	'
Business Acquisition [Line Items]	'	'	'
Combined annual capacity	1,500,000,000	'	'
Caustic Soda [Member]	'	'	'
Business Acquisition [Line Items]	'	'	'
Combined annual capacity	1,000,000,000	'	'

Acquisitions_Pro_Forma_Informa

Acquisitions (Pro Forma Information) (Details) (Vinnolit [Member], USD $)	9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Vinnolit [Member]	'	'
Pro Forma Information:	'	'
Net sales	$4,016,935	$3,747,619
Net income	550,667	480,964
Net income attributable to noncontrolling interests	2,399	0
Net income attributable to Westlake Chemical Corporation	$548,268	$480,964
Earnings per common share attributable to Westlake Chemical Corporation:	'	'
Basic, in dollars per share	$4.11	$3.59
Diluted, in dollars per share	$4.09	$3.58

Acquisitions_Purchase_Consider

Acquisitions (Purchase Consideration Transferred) (Details) (Vinnolit [Member], USD $)	0 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014		Jul. 31, 2014
Business Acquisition [Line Items]	'		'
Cash paid to Sellers	$309,619		'
Cash deposited in escrow	13,390	[1]	'
Retirement of long-term debt as of July 31, 2014, on behalf of the Sellers	413,215	[2]	'
Total purchase consideration	736,224		'
Assets:	'		'
Cash	'		125,137
Working capital, excluding inventory and cash	'		23,072	[3]
Inventories	'		114,961	[4]
Property, plant and equipment	'		471,123
Investments	'		51,552
Other assets	'		65,366	[5]
Intangible assets:	'		'
Deferred income tax asset - current	'		8,697
Deferred income tax asset - non-current	'		27,387
Liabilities:	'		'
Pension obligation	'		-117,970
Other long-term liabilities	'		-10,723
Power purchase agreement liability	'		-10,826	[6]
Deferred income tax liability - current	'		-6,845
Deferred income tax liability - non-current	'		-77,899
Total identifiable net assets	'		736,224
Goodwill	'		0	[7]
Consideration transferred	'		736,224
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables	'		181,826	[3]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables, Gross Contractual Amount	'		183,769	[3]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Uncollectable Receivables	'		1,943	[3]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory Adjustment	'		16,900	[3]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Power Purchase Agreement Liability, Weighted Average Life	'36 months	[2]	'
Trademarks and Trade Names [Member]	'		'
Business Acquisition [Line Items]	'		'
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	'20 years		'
Intangible assets:	'		'
Intangible assets	'		40,170
Developed Technology Rights [Member]	'		'
Business Acquisition [Line Items]	'		'
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	'20 years		'
Intangible assets:	'		'
Intangible assets	'		31,600
Other Intangible Assets [Member]	'		'
Business Acquisition [Line Items]	'		'
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	'9 years 4 months 24 days		'
Intangible assets:	'		'
Intangible assets	'		$1,422
[1]	None of the cash held in escrow is considered contingent consideration as it is expected to be released to the Sellers pending the Sellersb satisfaction of general representations and warranties made in connection with the execution of the purchase agreement.
[2]	Vinnolitbs long-term debt paid on behalf of the Sellers was not legally assumed by Westlake in the acquisition and was a condition of the consummation of the purchase agreement. Therefore, the retirement has been included in the total purchase consideration.
[3]	The fair value of accounts receivable acquired is $181,826, with the gross contractual amount being $183,769. The Company expects $1,943 to be uncollectible.
[4]	An adjustment of approximately $16,900 was recorded to reflect Vinnolit's inventories at fair value and increased cost of sales by the same amount for the three months ended September 30, 2014.
[5]	Included in other assets was a loan acquired that was repaid prior to September 30, 2014.
[6]	A liability arising from unfavorable forward purchase contracts for the purchase of power was recognized at fair value. This liability will be amortized over a period of approximately 3.0 years, being the weighted-average life of the forward purchase contracts.
[7]	Management estimated that the fair value of the net assets acquired equals consideration paid. Therefore, no goodwill was recorded.

Related_Party_and_Affiliate_Tr1

Related Party and Affiliate Transactions (Details) (Affiliated Entity [Member], USD $)	2 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014
InfraServ Knapsack GmbH & Co. KG [Member]	'
Related Party Transaction [Line Items]	'
Ownership percentage in provider	15.00%
InfraServ Knapsack GmbH & Co. KG [Member] | Electricity And Technical Services [Member]	'
Related Party Transaction [Line Items]	'
Amount of charges incurred during period	$11,581
InfraServ Gendorf GmbH & Co. KG [Member]	'
Related Party Transaction [Line Items]	'
Ownership percentage in provider	11.00%
InfraServ Gendorf GmbH & Co. KG [Member] | Electricity And Technical Services [Member]	'
Related Party Transaction [Line Items]	'
Amount of charges incurred during period	$10,489

Guarantor_Disclosures_Addition

Guarantor Disclosures (Additional Information) (Detail) (USD $)	3 Months Ended	0 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Aug. 04, 2014	Aug. 04, 2014
	3.60% Senior Notes Due 2022	Limited Partner [Member]	Limited Partner [Member]
		IPO [Member]	Westlake Chemical Partners LP [Member]
			Subsidiaries [Member]
			IPO [Member]
Condensed Financial Statements, Captions [Line Items]	'	'	'
Stated interest rate	3.60%	'	'
Maturity	'2022	'	'
Minimum debt amount guaranteed by subsidiaries	$5,000	'	'
Limited partner interest	'	89.40%	10.60%

Guarantor_Disclosures_Condense

Guarantor Disclosures (Condensed Consolidating Financial Information Balance Sheets) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	$813,468	$461,301	$591,556	$790,078
Marketable Securities, Current	0	239,388	'	'
Accounts receivable, net	592,964	428,457	'	'
Inventories	500,552	471,879	'	'
Prepaid expenses and other current assets	18,884	13,888	'	'
Deferred income taxes	26,080	34,169	'	'
Total current assets	1,951,948	1,649,082	'	'
Property, plant and equipment, net	2,710,475	2,088,014	'	'
Equity investments	70,828	66,875	'	'
Other assets, net	393,032	256,938	'	'
Total assets	5,126,283	4,060,909	'	'
Accounts payable	263,365	249,613	'	'
Accrued liabilities	309,671	155,245	'	'
Total current liabilities	573,036	404,858	'	'
Long-term debt	763,968	763,879	'	'
Deferred income taxes	513,773	437,976	'	'
Other liabilities	153,158	35,593	'	'
Total liabilities	2,003,935	1,642,306	'	'
Total Westlake Chemical Corporation stockholders' equity	2,833,861	2,418,603	'	'
Noncontrolling interests	288,487	0	'	'
Total equity	3,122,348	2,418,603	'	1,872,256
Total liabilities and equity	5,126,283	4,060,909	'	'
Westlake Chemical Corporation	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	652,709	420,948	560,261	753,881
Marketable Securities, Current	'	239,388	'	'
Accounts receivable, net	15,064	3,879	'	'
Inventories	0	0	'	'
Prepaid expenses and other current assets	137	778	'	'
Deferred income taxes	342	441	'	'
Total current assets	668,252	665,434	'	'
Property, plant and equipment, net	0	0	'	'
Equity investments	3,878,703	2,815,752	'	'
Other assets, net	34,847	15,393	'	'
Total assets	4,581,802	3,496,579	'	'
Accounts payable	979,414	316,652	'	'
Accrued liabilities	15,448	8,334	'	'
Total current liabilities	994,862	324,986	'	'
Long-term debt	753,079	752,990	'	'
Deferred income taxes	0	0	'	'
Other liabilities	0	0	'	'
Total liabilities	1,747,941	'	'	'
Total Westlake Chemical Corporation stockholders' equity	2,833,861	2,418,603	'	'
Noncontrolling interests	0	'	'	'
Total equity	2,833,861	'	'	'
Total liabilities and equity	4,581,802	3,496,579	'	'
100% Owned Guarantor Subsidiaries	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	1,644	6,227	4,494	6,973
Marketable Securities, Current	'	0	'	'
Accounts receivable, net	1,377,250	666,344	'	'
Inventories	385,826	339,929	'	'
Prepaid expenses and other current assets	14,737	11,055	'	'
Deferred income taxes	25,446	28,974	'	'
Total current assets	1,804,903	1,052,529	'	'
Property, plant and equipment, net	1,451,807	1,318,119	'	'
Equity investments	1,207,569	636,461	'	'
Other assets, net	351,271	423,901	'	'
Total assets	4,815,550	3,431,010	'	'
Accounts payable	157,562	100,570	'	'
Accrued liabilities	238,225	134,452	'	'
Total current liabilities	395,787	235,022	'	'
Long-term debt	10,889	10,889	'	'
Deferred income taxes	473,343	260,171	'	'
Other liabilities	31,616	34,571	'	'
Total liabilities	911,635	'	'	'
Total Westlake Chemical Corporation stockholders' equity	3,903,915	2,890,357	'	'
Noncontrolling interests	0	'	'	'
Total equity	3,903,915	'	'	'
Total liabilities and equity	4,815,550	3,431,010	'	'
OpCo (Less Than 100% Owned Guarantor Subsidiary)	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	89,144	0	0	0
Marketable Securities, Current	'	0	'	'
Accounts receivable, net	58,106	71,812	'	'
Inventories	5,551	116,377	'	'
Prepaid expenses and other current assets	303	257	'	'
Deferred income taxes	0	4,448	'	'
Total current assets	153,104	192,894	'	'
Property, plant and equipment, net	806,648	762,972	'	'
Equity investments	0	10,411	'	'
Other assets, net	61,679	75,197	'	'
Total assets	1,021,431	1,041,474	'	'
Accounts payable	29,856	122,564	'	'
Accrued liabilities	3,412	26,688	'	'
Total current liabilities	33,268	149,252	'	'
Long-term debt	188,523	252,973	'	'
Deferred income taxes	1,507	182,855	'	'
Other liabilities	0	962	'	'
Total liabilities	223,298	'	'	'
Total Westlake Chemical Corporation stockholders' equity	798,133	455,432	'	'
Noncontrolling interests	0	'	'	'
Total equity	798,133	'	'	'
Total liabilities and equity	1,021,431	1,041,474	'	'
Non-Guarantor Subsidiaries	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	69,971	34,126	26,801	29,224
Marketable Securities, Current	'	0	'	'
Accounts receivable, net	170,833	2,755	'	'
Inventories	109,175	15,573	'	'
Prepaid expenses and other current assets	3,707	1,798	'	'
Deferred income taxes	292	306	'	'
Total current assets	353,978	54,558	'	'
Property, plant and equipment, net	452,020	6,923	'	'
Equity investments	356,286	31,518	'	'
Other assets, net	137,990	1,199	'	'
Total assets	1,300,274	94,198	'	'
Accounts payable	100,129	10,649	'	'
Accrued liabilities	77,279	1,282	'	'
Total current liabilities	177,408	11,931	'	'
Long-term debt	0	0	'	'
Deferred income taxes	43,155	729	'	'
Other liabilities	121,542	60	'	'
Total liabilities	342,105	'	'	'
Total Westlake Chemical Corporation stockholders' equity	669,682	81,478	'	'
Noncontrolling interests	288,487	'	'	'
Total equity	958,169	'	'	'
Total liabilities and equity	1,300,274	94,198	'	'
Eliminations	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	0	0	0	0
Marketable Securities, Current	'	0	'	'
Accounts receivable, net	-1,028,289	-316,333	'	'
Inventories	0	0	'	'
Prepaid expenses and other current assets	0	0	'	'
Deferred income taxes	0	0	'	'
Total current assets	-1,028,289	-316,333	'	'
Property, plant and equipment, net	0	0	'	'
Equity investments	-5,371,730	-3,427,267	'	'
Other assets, net	-192,755	-258,752	'	'
Total assets	-6,592,774	-4,002,352	'	'
Accounts payable	-1,003,596	-300,822	'	'
Accrued liabilities	-24,693	-15,511	'	'
Total current liabilities	-1,028,289	-316,333	'	'
Long-term debt	-188,523	-252,973	'	'
Deferred income taxes	-4,232	-5,779	'	'
Other liabilities	0	0	'	'
Total liabilities	-1,221,044	'	'	'
Total Westlake Chemical Corporation stockholders' equity	-5,371,730	-3,427,267	'	'
Noncontrolling interests	0	'	'	'
Total equity	-5,371,730	'	'	'
Total liabilities and equity	($6,592,774)	($4,002,352)	'	'

Guarantor_Disclosures_Condense1

Guarantor Disclosures (Condensed Consolidating Financial Information Statement of Operations) (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'
Net sales	$1,253,227	$1,004,165	$3,279,479	$2,807,859	'
Cost of sales	891,707	699,694	2,324,978	2,002,092	'
Gross profit	361,520	304,471	954,501	805,767	'
Selling, general and administrative expenses	54,759	37,869	132,897	109,883	'
Income from operations	306,761	266,602	821,604	695,884	'
Interest expense	-9,486	-3,297	-28,182	-14,921	'
Other (expense) income, net	-2,670	-287	4,440	3,137	'
Income before income taxes	294,605	263,018	797,862	684,100	'
Provision for (benefit from) income taxes	124,449	92,728	300,231	244,647	'
Equity in net income of subsidiaries	0	0	0	0	'
Net income	170,156	170,290	497,631	439,453	610,425
Net income attributable to noncontrolling interests	2,399	0	2,399	0	'
Net income to Westlake Chemical Corporation	167,757	170,290	495,232	439,453	'
Comprehensive income (loss)	131,456	171,095	461,415	439,372	'
Westlake Chemical Corporation	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'
Net sales	0	0	0	0	'
Cost of sales	0	0	0	0	'
Gross profit	0	0	0	0	'
Selling, general and administrative expenses	399	514	1,474	1,576	'
Income from operations	-399	-514	-1,474	-1,576	'
Interest expense	-10,343	-3,292	-29,032	-14,882	'
Other (expense) income, net	2,138	3,585	14,488	7,490	'
Income before income taxes	-8,604	-221	-16,018	-8,968	'
Provision for (benefit from) income taxes	-3,088	-70	-5,686	-3,202	'
Equity in net income of subsidiaries	173,273	170,441	505,564	445,219	'
Net income	167,757	'	495,232	439,453	'
Net income attributable to noncontrolling interests	0	'	0	'	'
Net income to Westlake Chemical Corporation	167,757	170,290	495,232	439,453	'
Comprehensive income (loss)	131,456	171,095	461,415	439,372	'
100% Owned Guarantor Subsidiaries	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'
Net sales	1,026,282	844,081	2,809,844	2,407,341	'
Cost of sales	831,675	754,037	2,476,608	2,247,338	'
Gross profit	194,607	90,044	333,236	160,003	'
Selling, general and administrative expenses	36,445	29,323	123,050	84,152	'
Income from operations	158,162	60,721	210,186	75,851	'
Interest expense	-2	-5	-8	-39	'
Other (expense) income, net	-2,942	-2,688	-1,729	-4,002	'
Income before income taxes	155,218	58,028	208,449	71,810	'
Provision for (benefit from) income taxes	93,366	19,973	109,920	27,292	'
Equity in net income of subsidiaries	113,157	132,581	410,875	402,340	'
Net income	175,009	'	509,404	446,858	'
Net income attributable to noncontrolling interests	0	'	0	'	'
Net income to Westlake Chemical Corporation	175,009	170,636	509,404	446,858	'
Comprehensive income (loss)	175,137	170,764	509,787	447,490	'
OpCo (Less Than 100% Owned Guarantor Subsidiary)	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'
Net sales	392,008	540,133	1,476,157	1,565,809	'
Cost of sales	227,015	327,152	832,304	924,663	'
Gross profit	164,993	212,981	643,853	641,146	'
Selling, general and administrative expenses	8,014	6,391	21,957	19,326	'
Income from operations	156,979	206,590	621,896	621,820	'
Interest expense	-2,137	-2,295	-9,833	-4,893	'
Other (expense) income, net	486	1,162	3,135	6,422	'
Income before income taxes	155,328	205,457	615,198	623,349	'
Provision for (benefit from) income taxes	36,309	72,876	198,461	221,009	'
Equity in net income of subsidiaries	0	0	0	0	'
Net income	119,019	'	416,737	402,340	'
Net income attributable to noncontrolling interests	0	'	0	'	'
Net income to Westlake Chemical Corporation	119,019	132,581	416,737	402,340	'
Comprehensive income (loss)	119,019	132,581	416,737	402,340	'
Non-Guarantor Subsidiaries	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'
Net sales	208,313	13,337	229,183	37,561	'
Cost of sales	202,110	11,891	221,233	32,943	'
Gross profit	6,203	1,446	7,950	4,618	'
Selling, general and administrative expenses	14,184	1,641	16,954	4,829	'
Income from operations	-7,981	-195	-9,004	-211	'
Interest expense	-39	0	-39	0	'
Other (expense) income, net	683	-51	-724	-1,880	'
Income before income taxes	-7,337	-246	-9,767	-2,091	'
Provision for (benefit from) income taxes	-2,138	-51	-2,464	-452	'
Equity in net income of subsidiaries	5,862	0	5,862	0	'
Net income	663	'	-1,441	-1,639	'
Net income attributable to noncontrolling interests	2,399	'	2,399	'	'
Net income to Westlake Chemical Corporation	-1,736	-195	-3,840	-1,639	'
Comprehensive income (loss)	-39,528	351	-41,722	-2,483	'
Eliminations	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'
Net sales	-373,376	-393,386	-1,235,705	-1,202,852	'
Cost of sales	-369,093	-393,386	-1,205,167	-1,202,852	'
Gross profit	-4,283	0	-30,538	0	'
Selling, general and administrative expenses	-4,283	0	-30,538	0	'
Income from operations	0	0	0	0	'
Interest expense	3,035	2,295	10,730	4,893	'
Other (expense) income, net	-3,035	-2,295	-10,730	-4,893	'
Income before income taxes	0	0	0	0	'
Provision for (benefit from) income taxes	0	0	0	0	'
Equity in net income of subsidiaries	-292,292	-303,022	-922,301	-847,559	'
Net income	-292,292	'	-922,301	-847,559	'
Net income attributable to noncontrolling interests	0	'	0	'	'
Net income to Westlake Chemical Corporation	-292,292	-303,022	-922,301	-847,559	'
Comprehensive income (loss)	($254,628)	($303,696)	($884,802)	($847,347)	'

Guarantor_Disclosures_Condense2

Guarantor Disclosures (Condensed Consolidating Financial Information Statement of Cash Flows) (Details) (USD $)	9 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]	'	'	'
Net income	$497,631	$439,453	$610,425
Depreciation and amortization	149,566	117,387	'
Deferred income taxes	34,459	83,443	'
Net changes in working capital and other	94,468	-92,783	'
Net cash provided by operating activities	776,124	547,500	'
Acquisition of business, net of cash acquired	-611,087	-178,309	'
Additions to equity investments	0	-23,338	'
Additions to property, plant and equipment	-311,183	-498,290	'
Construction of assets pending sale-leaseback	0	-136	'
Proceeds from disposition of assets	145	78	'
Proceeds from repayment of loan acquired	45,923	0	'
Proceeds from repayment of loan to affiliate	0	167	'
Proceeds from sale and maturities of securities	342,045	239,764	'
Purchase of securities and other investments	-117,332	-232,286	'
Settlements of derivative instruments	-689	-2,297	'
Net cash used for investing activities	-652,178	-694,647	'
Intercompany financing	0	0	'
Net distributions prior to WLKP initial public offering	0	0	'
Capitalized debt issuance costs	-1,167	'	'
Dividends paid	-55,690	-40,204	'
Net proceeds from issuance of Westlake Chemical Partners LP common units	286,088	0	'
Purchase of limited partner interests	0	'	'
Proceeds from exercise of stock options	5,502	3,182	'
Repurchase of common stock for treasury	-9,495	-19,409	'
Windfall tax benefits from share-based payment arrangements	6,670	5,056	'
Net cash provided by financing activities	231,908	-51,375	'
Effect of exchange rate changes on cash	-3,687	0	'
Net increase in cash and cash equivalents	352,167	-198,522	'
Cash and cash equivalents at beginning of period	461,301	790,078	790,078
Cash and cash equivalents at end of period	813,468	591,556	461,301
Westlake Chemical Corporation	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Net income	495,232	439,453	'
Depreciation and amortization	1,172	1,094	'
Deferred income taxes	-418	-1,102	'
Net changes in working capital and other	-509,862	-458,336	'
Net cash provided by operating activities	-13,876	-18,891	'
Acquisition of business, net of cash acquired	0	0	'
Additions to equity investments	'	0	'
Additions to property, plant and equipment	0	0	'
Construction of assets pending sale-leaseback	'	0	'
Proceeds from disposition of assets	0	0	'
Proceeds from repayment of loan acquired	0	'	'
Proceeds from repayment of loan to affiliate	'	0	'
Proceeds from sale and maturities of securities	342,045	239,764	'
Purchase of securities and other investments	-117,332	-232,286	'
Settlements of derivative instruments	0	0	'
Net cash used for investing activities	224,713	7,478	'
Intercompany financing	75,104	-130,832	'
Net distributions prior to WLKP initial public offering	0	0	'
Capitalized debt issuance costs	-1,167	'	'
Dividends paid	-55,690	-40,204	'
Net proceeds from issuance of Westlake Chemical Partners LP common units	0	'	'
Purchase of limited partner interests	0	'	'
Proceeds from exercise of stock options	5,502	3,182	'
Repurchase of common stock for treasury	-9,495	-19,409	'
Windfall tax benefits from share-based payment arrangements	6,670	5,056	'
Net cash provided by financing activities	20,924	-182,207	'
Effect of exchange rate changes on cash	0	'	'
Net increase in cash and cash equivalents	231,761	-193,620	'
Cash and cash equivalents at beginning of period	420,948	753,881	753,881
Cash and cash equivalents at end of period	652,709	560,261	'
100% Owned Guarantor Subsidiaries	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Net income	509,404	446,858	'
Depreciation and amortization	82,597	59,893	'
Deferred income taxes	26,991	57,279	'
Net changes in working capital and other	-919,521	-421,066	'
Net cash provided by operating activities	-300,529	142,964	'
Acquisition of business, net of cash acquired	0	-178,309	'
Additions to equity investments	'	-23,338	'
Additions to property, plant and equipment	-160,147	-337,158	'
Construction of assets pending sale-leaseback	'	-136	'
Proceeds from disposition of assets	144	6	'
Proceeds from repayment of loan acquired	0	'	'
Proceeds from repayment of loan to affiliate	'	0	'
Proceeds from sale and maturities of securities	0	0	'
Purchase of securities and other investments	0	0	'
Settlements of derivative instruments	-556	0	'
Net cash used for investing activities	-160,559	-538,935	'
Intercompany financing	-143,325	-28,499	'
Net distributions prior to WLKP initial public offering	448,101	421,991	'
Capitalized debt issuance costs	0	'	'
Dividends paid	151,729	0	'
Net proceeds from issuance of Westlake Chemical Partners LP common units	0	'	'
Purchase of limited partner interests	0	'	'
Proceeds from exercise of stock options	0	0	'
Repurchase of common stock for treasury	0	0	'
Windfall tax benefits from share-based payment arrangements	0	0	'
Net cash provided by financing activities	456,505	393,492	'
Effect of exchange rate changes on cash	0	'	'
Net increase in cash and cash equivalents	-4,583	-2,479	'
Cash and cash equivalents at beginning of period	6,227	6,973	6,973
Cash and cash equivalents at end of period	1,644	4,494	'
OpCo (Less Than 100% Owned Guarantor Subsidiary)	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Net income	416,737	402,340	'
Depreciation and amortization	58,501	54,539	'
Deferred income taxes	8,267	27,253	'
Net changes in working capital and other	1,641	-68,604	'
Net cash provided by operating activities	485,146	415,528	'
Acquisition of business, net of cash acquired	0	0	'
Additions to equity investments	'	0	'
Additions to property, plant and equipment	-144,348	-158,869	'
Construction of assets pending sale-leaseback	'	0	'
Proceeds from disposition of assets	0	0	'
Proceeds from repayment of loan acquired	0	'	'
Proceeds from repayment of loan to affiliate	'	0	'
Proceeds from sale and maturities of securities	0	0	'
Purchase of securities and other investments	0	0	'
Settlements of derivative instruments	-133	-2,297	'
Net cash used for investing activities	-144,481	-161,166	'
Intercompany financing	62,221	167,629	'
Net distributions prior to WLKP initial public offering	-448,101	-421,991	'
Capitalized debt issuance costs	0	'	'
Dividends paid	-151,729	0	'
Net proceeds from issuance of Westlake Chemical Partners LP common units	0	'	'
Purchase of limited partner interests	286,088	'	'
Proceeds from exercise of stock options	0	0	'
Repurchase of common stock for treasury	0	0	'
Windfall tax benefits from share-based payment arrangements	0	0	'
Net cash provided by financing activities	-251,521	-254,362	'
Effect of exchange rate changes on cash	0	'	'
Net increase in cash and cash equivalents	89,144	0	'
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	89,144	0	'
Non-Guarantor Subsidiaries	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Net income	-1,441	-1,639	'
Depreciation and amortization	7,296	1,861	'
Deferred income taxes	-381	13	'
Net changes in working capital and other	599,909	7,664	'
Net cash provided by operating activities	605,383	7,899	'
Acquisition of business, net of cash acquired	-611,087	0	'
Additions to equity investments	'	0	'
Additions to property, plant and equipment	-6,688	-2,263	'
Construction of assets pending sale-leaseback	'	0	'
Proceeds from disposition of assets	1	72	'
Proceeds from repayment of loan acquired	45,923	'	'
Proceeds from repayment of loan to affiliate	'	167	'
Proceeds from sale and maturities of securities	0	0	'
Purchase of securities and other investments	0	0	'
Settlements of derivative instruments	0	0	'
Net cash used for investing activities	-571,851	-2,024	'
Intercompany financing	6,000	-8,298	'
Net distributions prior to WLKP initial public offering	0	0	'
Capitalized debt issuance costs	0	'	'
Dividends paid	0	0	'
Net proceeds from issuance of Westlake Chemical Partners LP common units	286,088	'	'
Purchase of limited partner interests	-286,088	'	'
Proceeds from exercise of stock options	0	0	'
Repurchase of common stock for treasury	0	0	'
Windfall tax benefits from share-based payment arrangements	0	0	'
Net cash provided by financing activities	6,000	-8,298	'
Effect of exchange rate changes on cash	-3,687	'	'
Net increase in cash and cash equivalents	35,845	-2,423	'
Cash and cash equivalents at beginning of period	34,126	29,224	29,224
Cash and cash equivalents at end of period	69,971	26,801	'
Eliminations	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Net income	-922,301	-847,559	'
Depreciation and amortization	0	0	'
Deferred income taxes	0	0	'
Net changes in working capital and other	922,301	847,559	'
Net cash provided by operating activities	0	0	'
Acquisition of business, net of cash acquired	0	0	'
Additions to equity investments	'	0	'
Additions to property, plant and equipment	0	0	'
Construction of assets pending sale-leaseback	'	0	'
Proceeds from disposition of assets	0	0	'
Proceeds from repayment of loan acquired	0	'	'
Proceeds from repayment of loan to affiliate	'	0	'
Proceeds from sale and maturities of securities	0	0	'
Purchase of securities and other investments	0	0	'
Settlements of derivative instruments	0	0	'
Net cash used for investing activities	0	0	'
Intercompany financing	0	0	'
Net distributions prior to WLKP initial public offering	0	0	'
Capitalized debt issuance costs	0	'	'
Dividends paid	0	0	'
Net proceeds from issuance of Westlake Chemical Partners LP common units	0	'	'
Purchase of limited partner interests	0	'	'
Proceeds from exercise of stock options	0	0	'
Repurchase of common stock for treasury	0	0	'
Windfall tax benefits from share-based payment arrangements	0	0	'
Net cash provided by financing activities	0	0	'
Effect of exchange rate changes on cash	0	'	'
Net increase in cash and cash equivalents	0	0	'
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	$0	$0	'