Westlake (WLK) 10-Q 3 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Jul. 27, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Trading Symbol	WLK
Entity Registrant Name	WESTLAKE CHEMICAL CORP
Entity Central Index Key	1,262,823
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		129,055,381

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 395,776	$ 459,453
Accounts receivable, net	1,095,808	938,743
Inventories	831,700	801,100
Prepaid expenses and other current assets	45,744	48,493
Restricted cash	8,607	160,527
Total current assets	2,377,635	2,408,316
Property, plant and equipment, net	6,316,731	6,420,062
Other assets, net
Goodwill	999,614	946,553
Customer relationships, net	654,092	611,615
Other intangible assets, net	169,991	175,839
Deferred charges and other assets, net	367,644	327,868
Total other assets, net	2,191,341	2,061,875
Total assets	10,885,707	10,890,253
Current liabilities
Accounts payable	583,509	496,259
Accrued liabilities	447,412	537,483
Term loan	0	149,341
Total current liabilities	1,030,921	1,183,083
Long-term debt, net	3,489,900	3,678,654
Deferred income taxes	1,648,529	1,650,575
Pension and other post-retirement benefits	366,916	364,819
Other liabilities	140,398	121,077
Total liabilities	6,676,664	6,998,208
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; 134,651,380 and 134,651,380 shares issued at June 30, 2017 and December 31, 2016, respectively	1,347	1,347
Common stock, held in treasury, at cost; 5,598,476 and 5,726,377 shares at June 30, 2017 and December 31, 2016, respectively	(316,152)	(319,339)
Additional paid-in capital	555,478	550,641
Retained earnings	3,653,988	3,412,286
Accumulated other comprehensive loss	(53,824)	(121,306)
Total Westlake Chemical Corporation stockholders' equity	3,840,837	3,523,629
Noncontrolling interests	368,206	368,416
Total equity	4,209,043	3,892,045
Total liabilities and equity	$ 10,885,707	$ 10,890,253

Consolidated Balance Sheets (U3

Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, par value, in dollars per share	$ 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, in dollars per share	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	134,651,312	134,651,380
Common stock, shares held in treasury	5,598,476	5,726,377

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Net sales	$ 1,979,161	$ 1,086,061	$ 3,921,777	$ 2,061,248
Cost of sales	1,573,327	844,695	3,148,800	1,564,297
Gross profit	405,834	241,366	772,977	496,951
Selling, general and administrative expenses	130,626	53,719	254,277	107,028
Transaction and integration-related costs	8,092	7,709	16,286	7,709
Income (loss) from operations	267,116	179,938	502,414	382,214
Interest Expense	(38,972)	(5,915)	(78,748)	(12,600)
Other income (expense)
Other income (expense), net	(538)	8,181	4,533	10,826
Income before income taxes	227,606	182,204	428,199	380,440
Provision for income taxes	68,188	66,584	124,071	135,884
Net income	159,418	115,620	304,128	244,556
Net income attributable to noncontrolling interests	6,591	4,496	13,111	10,304
Net income attributable to Westlake Chemical Corporation	$ 152,827	$ 111,124	$ 291,017	$ 234,252
Earnings per common share attributable to Westlake Chemical Corporation:
Basic (usd per share)	$ 1.18	$ 0.85	$ 2.24	$ 1.80
Diluted (usd per share)	$ 1.17	$ 0.85	$ 2.23	$ 1.79
Weighted average common shares outstanding:
Basic (in shares)	129,051,227	129,583,224	129,015,507	129,886,594
Diluted (in shares)	129,786,714	129,980,527	129,739,643	130,290,521
Dividends per common share (usd per share)	$ 0.1906	$ 0.1815	$ 0.3812	$ 0.3630

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 159,418	$ 115,620	$ 304,128	$ 244,556
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments and Tax	0	(206)	0	(206)
Pension and other post-retirement benefits liability
Amortization of benefits liability	499	369	1,071	703
Income tax provision on pension and other post- retirement benefits liability	(179)	(63)	(350)	(191)
Foreign currency translation	49,326	(13,500)	68,452	9,305
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	255	0	(1,527)	0
Net unrealized holding gains (losses) on investments
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax	0	35,545	0	59,973
Reclassification of net realized gains to net income	0	(1,267)	0	(1,319)
Income tax provision on available-for-sale investments	0	(12,316)	0	(21,074)
Other	(89)	0	(164)	0
Other comprehensive income, net of income taxes	49,812	8,562	67,482	47,191
Comprehensive income	209,230	124,182	371,610	291,747
Comprehensive income attributable to noncontrolling interests, net of tax of $808 and $0 for the three months ended June 30, 2017 and 2016, respectively; and $1,621 and $0 for the six months ended June 30, 2017 and 2016, respectively.	6,140	4,496	15,823	10,304
Comprehensive income attributable to Westlake Chemical Corporation	$ 203,090	$ 119,686	$ 355,787	$ 281,443

Consolidated Statements of Com6

Consolidated Statements of Comprehensive Income (Unaudited) OCI Parenthetical - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
OCI Parenthetical [Abstract]
Other Comprehensive Income (Loss), Tax, Portion Attributable to Noncontrolling Interest	$ 808	$ 0	$ 1,621	$ 0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities
Net income	$ 304,128	$ 244,556
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	294,899	132,964
Provision for doubtful accounts	930	403
Amortization of debt issuance costs	1,078	417
Stock-based compensation expense	10,768	5,084
Loss from disposition of property, plant and equipment	7,210	3,331
Gains realized from sales of securities	0	(1,319)
Write-off of debt issuance costs	659	0
Deferred income taxes	14,962	102,990
Windfall tax benefits from share-based payment arrangements	0	(319)
Dividends in excess of income from equity method investments	152	279
Gain on involuntary conversion of assets	(1,672)	0
Other losses (gains), net	(1,959)	1,210
Changes in operating assets and liabilities, net of effect of business acquisitions
Accounts receivable	(142,029)	(72,996)
Inventories	21,207	(12,719)
Prepaid expenses and other current assets	5,210	(12,586)
Accounts payable	82,030	54,394
Accrued liabilities	(87,277)	(1,617)
Other, net	(30,582)	(74,180)
Net cash provided by (used for) operating activities	479,714	369,892
Cash flows from investing activities
Additions to property, plant and equipment	(280,902)	(287,160)
Additions to cost method investment	(31,000)	0
Proceeds from disposition of assets	133	105
Proceeds from involuntary conversion of assets	1,672	0
Proceeds from sales and maturities of securities	0	302,432
Purchase of securities	0	(138,422)
Settlements of derivative instruments	(376)	(3,372)
Net cash used for investing activities	(310,473)	(126,417)
Cash flows from financing activities
Debt issuance costs	(376)	(9,700)
Dividends paid	(49,315)	(47,317)
Distributions to noncontrolling interests	(16,033)	(8,084)
Proceeds from issuance of notes payable	3,544	3,842
Proceeds from drawdown of revolver	175,000	0
Restricted cash associated with term loan	154,000	0
Repayment of term loan	(150,000)	0
Repayments of Notes Payable	4,901	8,626
Repayment of revolver	(360,000)	0
Repurchase of common stock for treasury	0	(67,404)
Other	1,477	800
Net cash provided by (used for) financing activities	(246,604)	(136,489)
Effect of exchange rate changes on cash and cash equivalents	13,686	1,486
Net increase (decrease) in cash and cash equivalents	(63,677)	108,472
Cash and cash equivalents at beginning of period	459,453	662,525
Cash and cash equivalents at end of period	$ 395,776	$ 770,997

Basis of Financial Statements

Basis of Financial Statements	6 Months Ended
	Jun. 30, 2017
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, 2016 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, 2016 (the " 2016 Form 10-K"), filed with the SEC on February 22, 2017 . 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, 2016 . 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 June 30, 2017 , its results of operations for the three and six months ended June 30, 2017 and 2016 and the changes in its cash position for the six months ended June 30, 2017 and 2016 . 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, 2017 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. Recent Accounting Pronouncements Revenue from Contracts with Customers (ASU No. 2014-09) 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. In 2016, the FASB issued various additional authoritative guidance for the new revenue recognition standard. The accounting standard will be effective for reporting periods beginning after December 15, 2017. The Company is in the process of evaluating the impact that the new accounting standard will have on its consolidated financial position, results of operations and cash flows. The Company has completed a preliminary assessment including detailed review of a representative sample of contracts with customers. The Company does not believe that adoption of the new accounting standard will significantly impact timing or amounts of revenue recognized for the majority of its sales. The Company intends to elect the modified retrospective method of adoption. Recognition and Measurement of Financial Assets and Financial Liabilities (ASU No. 2016-01) In January 2016, the FASB issued an accounting standards update making certain changes principally to the current guidance for equity investments, financial liabilities under the fair value option and the presentation and disclosure requirements for financial instruments. Among other things, the guidance (1) requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value, with changes in fair value recognized in net income; (2) provide entities with a policy election to record equity investments without readily determinable fair values at cost, less impairment, and subsequent adjustments for observable price changes (changes in the basis of these equity investments to be reported in net income); (3) requires an entity that has elected the fair value option for financial liabilities to recognize changes in fair value due to instrument-specific credit risk separately in other comprehensive income; (4) clarified current guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale debt securities; and (5) requires specific disclosure pertaining to financial assets and financial liabilities in the financial statements. The accounting standard will be effective for reporting periods beginning after December 15, 2017. 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. Leases (ASU No. 2016-02) In February 2016, the FASB issued an accounting standards update on a new lease standard that will supersede the existing lease guidance. The standard requires a lessee to recognize assets and liabilities related to long-term leases that are classified as operating leases under current guidance on its balance sheet. An asset would be recognized related to the right to use the underlying asset and a liability would be recognized related to the obligation to make lease payments over the term of the lease. The standard also requires expanded disclosures related to leases. The accounting standard will be effective for reporting periods beginning after December 15, 2018. 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. Credit Losses (ASU No. 2016-13) In June 2016, the FASB issued an accounting standards update providing new guidance for the accounting for credit losses on loans and other financial instruments. The new guidance introduces an approach based on expected losses to estimate credit losses on certain types of financial instruments. The standard also modifies the impairment model for available-for-sale debt securities and provides for a simplified accounting model for purchased financial assets with credit deterioration since their origination. The accounting standard will be effective for reporting periods beginning after December 15, 2019 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Cash Flows (ASU No. 2016-15) In August 2016, the FASB issued an accounting standards update providing new guidance on the classification of certain cash receipts and payments including debt extinguishment costs, debt prepayment costs, settlement of zero-coupon debt instruments, contingent consideration payments, proceeds from the settlement of insurance claims and life insurance policies and distributions received from equity method investees in the statement of cash flows. This update is required to be applied using the retrospective transition method to each period presented unless it is impracticable to be applied retrospectively. In such situation, this guidance is to be applied prospectively. The accounting standard will be effective for reporting periods beginning after December 15, 2017 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Cash Flows (ASU No. 2016-18) In November 2016, the FASB issued an accounting standards update to clarify certain existing principles in Accounting Standards Codification ("ASC") 230, Cash flows, including providing additional guidance related to transfers between cash and restricted cash and how entities present, in their statement of cash flows, the cash receipts and cash payments that directly affect the restricted cash accounts. The accounting standard will be effective for reporting periods beginning after December 15, 2017. Upon adoption of the accounting standards update, the Company will retrospectively adjust its financial statements to reflect restricted cash in the beginning and ending cash and restricted cash balances within the statements of cash flows. Transfers between cash and restricted cash will be excluded from net changes in cash and cash equivalents within the statements of cash flows. Business Combinations (ASU No. 2017-01) In January 2017, the FASB issued an accounting standards update to assist entities with evaluating when a set of transferred assets and activities is a business. The guidance requires an entity to evaluate if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets; if so, the set of transferred assets and activities is not a business. The guidance also requires a business to include at least one substantive process and narrows the definition of outputs by more closely aligning it with how outputs are described in the ASC 606, Revenue from contracts with customers. The accounting standard will be effective for reporting periods beginning after December 15, 2017 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Intangibles - Goodwill and Other (ASU No. 2017-04) In January 2017, the FASB issued an accounting standards update to simplify the subsequent measurement of goodwill. The guidance removes Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. A goodwill impairment will now be the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The accounting standard will be effective for reporting periods beginning after December 15, 2019 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (ASU No. 2017-05) In February 2017, the FASB issued an accounting standards update to clarify the scope of guidance related to other income — gains and losses from the derecognition of nonfinancial assets, and to add guidance for partial sales of nonfinancial assets. The new guidance clarifies that an in substance nonfinancial asset is an asset or group of assets for which substantially all of the fair value consists of nonfinancial assets and the group or subsidiary is not a business. The guidance also outlines that when an entity transfers its controlling interest in a nonfinancial asset, but retains a noncontrolling interest, it will measure the retained interest at fair value resulting in full gain or loss recognition upon sale of the controlling interest. The accounting standard will be effective for reporting periods beginning after December 15, 2017 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Compensation - Retirement Benefits (ASU No. 2017-07) In March 2017, the FASB issued an accounting standards update to improve the presentation of net periodic pension cost and net periodic postretirement benefit cost. The new guidance requires employers to disaggregate the service cost component from the other components of net periodic benefit cost and report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The amendments also allow only the service cost component to be eligible for capitalization when applicable. The accounting standard will be effective for reporting periods beginning after December 15, 2017. 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. Compensation - Stock Compensation (ASU No. 2017-09) In May 2017, the FASB issued the accounting standards update to provide clarity and reduce both (1) diversity in practice and (2) cost and complexity when applying the guidance in Topic 718, Compensation-Stock Compensation, to a change to the terms or conditions of a share-based payment award. The amendments in this update provide guidance about which changes to the terms or conditions of a share-based payment award require the application of modification accounting in Topic 718. Essentially, an entity will not have to account for the effects of a modification if: (1) the fair value of the modified award is the same immediately before and after the modification; (2) the vesting conditions of the modified award are the same immediately before and after the modification; and (3) the classification of the modified award as either an equity instrument or liability instrument is the same immediately before and after the modification. This update is to be applied prospectively to an award modified on or after the adoption date. The accounting standard will be effective for reporting periods beginning after December 15, 2017. Early adoption is permitted. 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. Recently Adopted Accounting Standards Investments - Equity Method and Joint Ventures (ASU No. 2016-07) In March 2016, the FASB issued an accounting standards update providing new guidance for the accounting for equity method investments. The new guidance eliminates the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. In addition, the guidance requires that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor's previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. Therefore, upon qualifying for the equity method of accounting, no retroactive adjustment of the investment is required. The accounting standard became effective for reporting periods beginning after December 15, 2016. The Company adopted this accounting standard effective January 1, 2017 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Stock Compensation (ASU No. 2016-09) In March 2016, the FASB issued an accounting standards update to simplify several aspects of the accounting for share-based payment transactions, including income tax consequences, classifications of awards as either equity or liabilities and certain related classifications on the statement of cash flows. In addition, the new guidance permits entities to make an accounting policy election for the impact of forfeitures on the recognition of expense for share-based payment awards. Forfeitures can be estimated, as required prior to adoption of the accounting standards update, or recognized when they occur. The accounting standard became effective for reporting periods beginning after December 15, 2016. The Company adopted this accounting standard effective January 1, 2017 and elected to continue estimating forfeitures as required prior to adoption of the accounting standards update. The adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Amendments to the Consolidation Analysis (ASU No. 2016-17) In October 2016, the FASB issued an accounting standards update making certain changes to the current consolidation guidance. The amendments affect reporting entities that are required to evaluate whether they should consolidate a variable interest entity in certain situations involving entities under common control. Specifically, the amendments change the evaluation of whether a reporting entity is the primary beneficiary of a variable interest entity by changing how a reporting entity that is a single decision maker of a variable interest entity treats indirect interests in the entity held through related parties that are under common control with the reporting entity. The amendments became effective for annual periods beginning after December 15, 2016. The Company adopted this accounting standard, to be applied prospectively, effective January 1, 2017, and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows.

Acquisition

Acquisition	6 Months Ended
	Jun. 30, 2017
Business Combinations [Abstract]
Acquisition	Acquisition On August 31, 2016, the Company completed its acquisition of, and acquired all the remaining equity interest in, Axiall Corporation ("Axiall"), a Delaware corporation. Prior to the acquisition, the Company held 3.1 million shares in Axiall. Pursuant to the terms of the Agreement and Plan of Merger, dated as of June 10, 2016, by and among Westlake, Axiall and Lagoon Merger Sub, Inc., a Delaware corporation that is a wholly-owned subsidiary of Westlake ("Merger Sub"), the Company acquired all of the remaining issued and outstanding shares of common stock of Axiall for $33.00 per share in cash. Pursuant to the Merger Agreement, Merger Sub was merged with and into Axiall and Axiall survived the Merger as a wholly-owned subsidiary of the Company. The combined company is the third-largest global chlor-alkali producer and the third-largest global polyvinyl chloride ("PVC") producer. The Company's management believes that this strategic acquisition will enhance its strategy of integration and will further strengthen its role in the North American markets. Axiall produces a highly integrated chain of chlor-alkali and derivative products, including chlorine, caustic soda, vinyl chloride monomer ("VCM"), PVC resin, PVC compounds and chlorinated derivative products. Axiall also manufactures and sells building products, including siding, trim, mouldings, pipe and pipe fittings. Total consideration transferred for the Merger was $2,539,360 . The Merger is being accounted for under the acquisition method of accounting. The assets acquired and liabilities assumed and the results of operations of the acquired business are included in the Company's Vinyls segment. The following table summarizes the consideration transferred and the estimated fair value of identified assets acquired and liabilities assumed at the date of acquisition. The preliminary allocation of the consideration transferred is based on management's estimates, judgments and assumptions. When determining the fair values of assets acquired, liabilities assumed and noncontrolling interests of the acquiree, management made significant 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 consideration paid exceeded the fair value of the net assets acquired. Therefore, goodwill of $934,715 was recorded. The goodwill recognized is primarily attributable to synergies related to the Company's vinyls integration strategy that are expected to arise from the Merger. All of the goodwill is assigned to the Company's Vinyls segment. As a portion of the goodwill arising from the Merger is attributable to foreign operations, there will be a continuing foreign currency impact to goodwill in the financial statements. Final Purchase Consideration as of August 31, 2016 Closing stock purchase: Offer per share $ 33.00 Multiplied by number of shares outstanding at acquisition 67,277 Fair value of Axiall shares outstanding purchased by the Company 2,220,141 Plus: Axiall debt repaid at acquisition 247,135 Seller's transaction costs paid by the Company (1) 47,458 Total fair value of consideration transferred 2,514,734 Fair value of Axiall share-based awards attributed to pre-combination service (2) 11,346 Additional settlement value of shares acquired 13,280 Purchase consideration 2,539,360 Fair value of previously held equity interest in Axiall (3) 102,300 Total fair value allocated to net assets acquired $ 2,641,660 _____________ (1) Transaction costs incurred by the seller included legal and advisory costs incurred for the benefit of Axiall's former shareholders and board of directors to evaluate the Company's initial Merger proposals, explore strategic alternatives and negotiate the purchase price. (2) The fair value of share-based awards attributable to pre-combination service includes the ratio of the pre-combination service performed to the original service period of the Axiall restricted share units and options, including related dividend equivalent rights. (3) Prior to the Merger, the Company owned 3.1 million shares in Axiall. The investment in Axiall was carried at estimated fair value with unrealized gains recorded as a component of accumulated other comprehensive loss in the consolidated balance sheet. The Company recognized a $49,080 gain for the investment in other income, net in the consolidated statements of operations upon gaining control. The Company is currently finalizing the estimates of the fair values of identified assets acquired and liabilities assumed. The final allocation of purchase consideration, based on final valuations, could include changes in the estimated fair value of inventories, property, plant and equipment, equity investments, customer relationships, trade names, developed technologies and other intangibles, deferred income taxes, assumed contingencies, asset retirement obligations and noncontrolling interests. The assumed contingencies relate to environmental liabilities, legal liabilities, asset retirement obligations and warranty reserves. The information below represents the preliminary purchase price allocation: Net Assets Acquired as of August 31, 2016 Cash $ 88,251 Accounts receivable (1) 422,274 Income tax receivable 50,980 Inventories (2) 349,205 Prepaid expenses and other current assets 55,462 Property, plant and equipment (2) 2,946,442 Customer relationships (weighted average lives of 9.8 years) (3) 670,000 Other intangible assets: Trade name (weighted average lives of 6.8 years) 50,000 Technology (weighted average lives of 5.4 years) 41,500 Supply contracts and leases (weighted average lives of 6.3 years) 27,288 Other assets 95,872 Total assets acquired 4,797,274 Accounts and notes payable 254,041 Interest payable 8,154 Income tax payable 1,607 Accrued compensation 44,186 Accrued liabilities 151,608 Deferred income taxes (4) 959,882 Tax reserve non-current 3,130 Pension and other post-retirement obligations 311,106 Other liabilities 101,325 Long-term debt 1,187,290 Total liabilities assumed 3,022,329 Total identifiable net assets acquired 1,774,945 Noncontrolling interest (68,000 ) Goodwill 934,715 Total fair value allocated to net assets acquired $ 2,641,660 ______________________________ (1) The fair value of accounts receivable acquired is $422,274 , with the gross contractual amount being $434,834 . The Company expects $12,560 to be uncollectible. (2) The Company obtained additional information related to its inventories and property, plant and equipment which led to an increase in inventories of $43,047 , a decrease in property, plant and equipment of $188,299 and a corresponding increase in goodwill of $145,252 . (3) The Company obtained additional information related to its customer relationships balances which led to an increase in customer relationships of $80,000 and a corresponding decrease in goodwill. (4) Decreases in the estimated fair values of identified assets acquired led to a decrease in deferred income taxes of $25,246 .

Financial Instruments

Financial Instruments	6 Months Ended
	Jun. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Financial Instruments	Financial Instruments Cash Equivalents The Company had $9,996 of held-to-maturity securities with original maturity of three months or less, primarily consisting of corporate debt securities, classified as cash equivalents at June 30, 2017. The Company had no held-to-maturity securities classified as cash equivalents at December 31, 2016. The Company's investment in held-to-maturity securities is held at amortized cost, which approximates fair value. Restricted Cash and Cash Equivalents The Company had restricted cash and cash equivalents of $31,538 at June 30, 2017 , which was primarily related to balances that are restricted for payment of distributions to certain of the Company's current and former employees. The Company had restricted cash and cash equivalents of $186,216 at December 31, 2016 , which was primarily related to balances deposited with and held as security by the lender under the Company's term loan facility and for distributions to certain of the Company's current and former employees. The current portion of restricted cash and cash equivalents was $8,607 and $160,527 at June 30, 2017 and December 31, 2016 , respectively. The noncurrent portion of restricted cash and cash equivalents was $22,931 and $25,689 at June 30, 2017 and December 31, 2016 , respectively, and is reflected in deferred charges and other assets, net in the consolidated balance sheets. Available-for-Sale Marketable Securities The Company had no available-for-sale securities at June 30, 2017 or at December 31, 2016 . There were no sales or maturities of available-for-sale securities during the three and six months ended June 30, 2017 . The proceeds from sales and maturities of available-for-sale securities included in the consolidated statement of cash flows and the gross realized gains and losses included in the consolidated statement of operations for the three and six months ended June 30, 2016 are reflected in the table below. The cost of securities sold was determined using the specific identification method. Three Months Ended June 30, Six Months Ended June 30, 2016 2016 Proceeds from sales and maturities of securities $ 275,573 $ 302,432 Gross realized gains 1,280 1,341 Gross realized losses (13 ) (22 )

Accounts Receivable

Accounts Receivable	6 Months Ended
	Jun. 30, 2017
Accounts Receivable, Net [Abstract]
Accounts Receivable	Accounts Receivable Accounts receivable consist of the following: June 30, December 31, Trade customers $ 1,031,060 $ 819,739 Affiliates 9,105 7,982 Allowance for doubtful accounts (19,602 ) (17,991 ) 1,020,563 809,730 Federal and state taxes 51,462 90,414 Other 23,783 38,599 Accounts receivable, net $ 1,095,808 $ 938,743

Inventories

Inventories	6 Months Ended
	Jun. 30, 2017
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consist of the following: June 30, December 31, Finished products $ 473,011 $ 500,861 Feedstock, additives and chemicals 226,562 216,877 Materials and supplies 132,127 83,362 Inventories $ 831,700 $ 801,100

Property, Plant and Equipment

Property, Plant and Equipment	6 Months Ended
	Jun. 30, 2017
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment As of June 30, 2017 , the Company had property, plant and equipment, net totaling $6,316,731 . 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 $104,294 and $57,930 is primarily included in cost of sales in the consolidated statements of operations for the three months ended June 30, 2017 and 2016 , respectively. Depreciation expense on property, plant and equipment of $218,385 and $113,971 is included in cost of sales in the consolidated statements of operations for the six months ended June 30, 2017 and 2016 , respectively.

Other Assets

Other Assets	6 Months Ended
	Jun. 30, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	Other Assets Amortization expense on intangible and other assets of $40,488 and $76,818 is primarily included in selling, general and administrative expenses in the consolidated statements of operations for the three and six months ended June 30, 2017 , respectively. Amortization expense on intangible and other assets of $9,269 and $19,163 is primarily included in cost of sales in the consolidated statements of operations for the three and six months ended June 30, 2016 , respectively. Goodwill The gross carrying amounts of goodwill and the changes in the carrying amount of goodwill for the six months ended June 30, 2017 were as follows: Olefins Segment Vinyls Segment Total Balance at December 31, 2016 $ 29,990 $ 916,563 $ 946,553 Goodwill acquired during the period — — — Measurement period adjustment — 47,224 47,224 Effects of changes in foreign exchange rates — 5,837 5,837 Balance at June 30, 2017 $ 29,990 $ 969,624 $ 999,614 The Company performed its annual impairment tests for the Vinyls reporting units in the second quarter of 2017 and did not identify any impairment.

Accounts and Notes Payable

Accounts and Notes Payable	6 Months Ended
	Jun. 30, 2017
Payables and Accruals [Abstract]
Accounts and Notes Payable	Accounts Payable Accounts payable consist of the following: June 30, December 31, Accounts payable—third parties $ 561,190 $ 474,017 Accounts payable to affiliates 21,615 20,726 Notes payable to banks 704 1,516 Accounts payable $ 583,509 $ 496,259

Term Loan

Term Loan	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Term Loan	Term Loan On August 10, 2016, an indirect subsidiary of the Company, Westlake International Holdings II C.V., a limited partnership organized under the laws of the Netherlands (the "CV Borrower"), entered into a credit agreement with Bank of America, N.A., as agent and lender, providing the CV Borrower with a $150,000 term loan facility. The term loan facility had a maturity date of March 31, 2017. The term loan was fully repaid in January 2017. The loans thereunder bore interest at a floating interest rate equal to LIBOR plus 2% per annum, payable in arrears on the last day of each three-month period following the date of funding and at maturity.

Long-Term Debt

Long-Term Debt	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt consists of the following: June 30, 2017 December 31, 2016 Principal Unamortized Discount Net Principal Unamortized Net Revolving credit facility $ 140,000 $ — $ 140,000 $ 325,000 $ — $ 325,000 4.625% senior notes due 2021 (the "4.625% Westlake 2021 Senior Notes") 624,793 23,502 648,295 624,793 26,837 651,630 4.625% senior notes due 2021 (the "4.625% Subsidiary 2021 Senior Notes") 63,207 2,518 65,725 63,207 2,862 66,069 3.60% senior notes due 2022 250,000 (1,720 ) 248,280 250,000 (1,891 ) 248,109 4.875% senior notes due 2023 (the "4.875% Westlake 2023 Senior Notes") 433,793 12,316 446,109 433,793 13,431 447,224 4.875% senior notes due 2023 (the "4.875% Subsidiary 2023 Senior Notes") 16,207 498 16,705 16,207 540 16,747 3.60% senior notes due 2026 (the "3.60% 2026 Senior Notes") 750,000 (10,312 ) 739,688 750,000 (10,757 ) 739,243 Loan related to tax-exempt waste disposal revenue bonds due 2027 10,889 — 10,889 10,889 — 10,889 6 ½% tax-exempt senior notes due 2029 100,000 (880 ) 99,120 100,000 (916 ) 99,084 6 ¾% tax-exempt senior notes due 2032 250,000 (1,824 ) 248,176 250,000 (1,883 ) 248,117 6 ½% tax-exempt senior notes due 2035 (the "6 ½% 2035 GO Zone Senior Notes") 89,000 (817 ) 88,183 89,000 (839 ) 88,161 6 ½% tax-exempt senior notes due 2035 (the "6 ½% 2035 IKE Zone Senior Notes") 65,000 (586 ) 64,414 65,000 (602 ) 64,398 5.0% senior notes due 2046 (the "5.0% 2046 Senior Notes") 700,000 (25,684 ) 674,316 700,000 (26,017 ) 673,983 Long-term debt, net $ 3,492,889 $ (2,989 ) $ 3,489,900 $ 3,677,889 $ 765 $ 3,678,654 Credit Agreement At June 30, 2017 , the Company had $140,000 of borrowings outstanding under the Credit Agreement. The interest rate on the borrowings outstanding under the revolving credit facility was 2.51% at June 30, 2017 . The Credit Agreement matures on August 23, 2021. As of June 30, 2017 , the Company had outstanding letters of credit totaling $76,525 and borrowing availability of $783,475 under the Credit Agreement. As of June 30, 2017 , the Company was in compliance with the total leverage ratio financial maintenance covenant. 3.60% Senior Notes due 2026 and 5.0% Senior Notes due 2046 In August 2016, the Company issued $750,000 aggregate principal amount of 3.60% senior notes due 2026 (the " 3.60% 2026 Senior Notes ") and $700,000 aggregate principal amount of 5.0% senior notes due 2046 (the " 5.0% 2046 Senior Notes "). On March 27, 2017, the Company commenced registered exchange offers to exchange the 3.60% 2026 Senior Notes and the 5.0% 2046 Senior Notes for new notes that are identical in all material respects to the 3.60% 2026 Senior Notes and the 5.0% 2046 Senior Notes, except that the offer and issuance of the new SEC-registered notes have been registered under the Securities Act of 1933, as amended (the “Securities Act”). The exchange offers expired on April 24, 2017, and approximately 99.97% of the 3.60% 2026 Senior Notes and 100.00% of the 5.0% 2046 Senior Notes were exchanged. The 3.60% 2026 Senior Notes that were not exchanged pursuant to the exchange offers have not been registered under the Securities Act or any state securities laws and may not be offered or sold in the United States absent registration or an applicable exemption from registration requirements or a transaction not subject to the registration requirements of the Securities Act or any state securities law. 4.625% Senior Notes due 2021 and 4.875% Senior Notes due 2023 In September 2016, the Company issued $624,793 aggregate principal amount of 4.625% senior notes due 2021 (the “ 4.625% Westlake 2021 Senior Notes ”) and $433,793 aggregate principal amount of 4.875% senior notes due 2023 (the “ 4.875% Westlake 2023 Senior Notes ”) upon the closing of the Company's offers to exchange any and all of the $688,000 aggregate principal amount of the outstanding 4.625% senior notes due 2021 issued by Eagle Spinco Inc., a wholly-owned subsidiary of Axiall (“Eagle Spinco”), and the $450,000 aggregate principal amount of the outstanding 4.875% senior notes due 2023 issued by Axiall. In the exchange offers, $624,793 aggregate principal amount of 4.625% Westlake 2021 Senior Notes and $433,793 aggregate principal amount of 4.875% Westlake 2023 Senior Notes were issued by the Company, leaving outstanding $63,207 aggregate principal amount of the 4.625% 2021 senior notes (the " 4.625% Subsidiary 2021 Senior Notes ") and $16,207 aggregate principal amount of the 4.875% 2023 senior notes (the " 4.875% Subsidiary 2023 Senior Notes "). On March 27, 2017, the Company commenced registered exchange offers to exchange the 4.625% Westlake 2021 Senior Notes and the 4.875% Westlake 2023 Senior Notes for new SEC-registered notes that are identical in all material respects to the 4.625% Westlake 2021 Senior Notes and the 4.875% Westlake 2023 Senior Notes , except that the offer and issuance of the new notes have been registered under the Securities Act. The exchange offers expired on April 24, 2017, and 100.00% of both the 4.625% Westlake 2021 Senior Notes and the 4.875% Westlake 2023 Senior Notes were exchanged. As of June 30, 2017, the Company was in compliance with all of the covenants with respect to the Credit Agreement, 3.60% 2026 Senior Notes , 5.0% 2046 Senior Notes , 4.625% Westlake 2021 Senior Notes , 4.875% Westlake 2023 Senior Notes , 3.60% Senior Notes Due 2022, 6 ½% tax-exempt senior notes due 2029, the 6 ¾% tax-exempt senior notes due 2032, the 6 ½% 2035 GO Zone Senior Notes, the 6 ½% 2035 IKE Zone Senior Notes and the waste disposal revenue bonds. Unamortized debt issuance costs on Long-term debt were $23,281 and $24,113 at June 30, 2017 and December 31, 2016 , respectively.

Pension and Post-Retirement Ben

Pension and Post-Retirement Benefits	6 Months Ended
	Jun. 30, 2017
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Pension and Post-Retirement Benefits	Pension and Post-Retirement Benefits In connection with the Merger, the Company assumed certain U.S. and non-U.S. pension plans and other post-retirement benefit plans covering Axiall employees. The Axiall pension plans are closed to new participants and provide benefits to certain employees and retirees. The other post-retirement benefit plans are unfunded and provide medical and life insurance benefits for certain employees and their dependents. See Note 2 for the fair value of pension and other post-retirement obligations assumed in the Merger. Defined Benefit Plans Components of net periodic benefit cost (income) for the Company's pension plans are as follows: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 U.S. Non-U.S. U.S. Non-U.S. U.S. Non-U.S. U.S. Non-U.S. Service cost $ 1,335 $ 496 $ — $ 137 $ 2,671 $ 981 $ — $ 462 Interest cost 6,198 576 493 582 12,396 1,139 1,060 1,149 Expected return on plan assets (9,976 ) (151 ) (658 ) — (19,952 ) (304 ) (1,460 ) — Amortization of net loss 298 153 337 — 595 304 640 — Net periodic benefit cost (income) $ (2,145 ) $ 1,074 $ 172 $ 719 $ (4,290 ) $ 2,120 $ 240 $ 1,611 The Company made $5,139 of contributions to its U.S. pension plans and $514 of contributions to its non-U.S. pension plans during the first six months of 2017 . The Company made no contributions to its U.S. and non-U.S. pension plans during the first six months of 2016. The Company's funding policy for its U.S. plans is consistent with the minimum funding requirements of federal law and regulations, and, based on preliminary estimates, the Company expects to make contributions of approximately $5,139 to its U.S. pension plans and approximately $273 to its non-U.S. pension plans during the remainder of the fiscal year ending December 31, 2017 . Other Post-retirement Benefits Components of net periodic benefit cost for the Company's other post-retirement benefits are as follows: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 U.S. Non-U.S. U.S. Non-U.S. U.S. Non-U.S. U.S. Non-U.S. Service cost $ 163 $ 13 $ 5 $ — $ 326 $ 27 $ 10 $ — Interest cost 499 32 145 — 999 65 290 — Amortization of net loss 15 — 32 — 30 — 63 — Net periodic benefit cost $ 677 $ 45 $ 182 $ — $ 1,355 $ 92 $ 363 $ —

Stockholders Equity

Stockholders Equity	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Changes in stockholders' equity for the six months ended June 30, 2017 and 2016 were as follows: Common Stock Common Stock, Held in Treasury Additional Paid-in Capital Retained Earnings Accumulated Other Comprehensive Income (Loss) Noncontrolling Interests Total Balances at December 31, 2016 $ 1,347 $ (319,339 ) $ 550,641 $ 3,412,286 $ (121,306 ) $ 368,416 $ 3,892,045 Net income — — — 291,017 — 13,111 304,128 Other comprehensive income (loss), net of income taxes: Pension and other post- retirement benefits liability — — — — 721 (44 ) 677 Foreign currency translation adjustments — — — — 66,925 2,756 69,681 Other — — — — (164 ) — (164 ) Shares issued—stock- based compensation — 3,187 (1,710 ) — — — 1,477 Stock-based compensation, net of tax on stock options exercised — — 6,547 — — — 6,547 Dividends declared — — — (49,315 ) — — (49,315 ) Distributions to noncontrolling interests — — — — — (16,033 ) (16,033 ) Balances at June 30, 2017 $ 1,347 $ (316,152 ) $ 555,478 $ 3,653,988 $ (53,824 ) $ 368,206 $ 4,209,043 Common Stock Common Stock, Held in Treasury Additional Paid-in Capital Retained Earnings Accumulated Other Comprehensive Income (Loss) Noncontrolling Interests Total Balances at December 31, 2015 $ 1,347 $ (258,312 ) $ 542,148 $ 3,109,987 $ (129,292 ) $ 296,053 $ 3,561,931 Net income — — — 234,252 — 10,304 244,556 Other comprehensive income (loss), net of income taxes Pension and other post- retirement benefits liability — — — — 306 — 306 Foreign currency translation adjustments — — — — 9,305 — 9,305 Net unrealized holding gains on investments — — — — 37,580 — 37,580 Common stock repurchased — (66,725 ) — — — — (66,725 ) Shares issued—stock- based compensation — 2,235 (1,754 ) — — — 481 Stock-based compensation, net of tax on stock options exercised — — 5,403 — — — 5,403 Dividends declared — — — (47,317 ) — — (47,317 ) Distributions to noncontrolling interests — — — — — (8,084 ) (8,084 ) Balances at June 30, 2016 $ 1,347 $ (322,802 ) $ 545,797 $ 3,296,922 $ (82,101 ) $ 298,273 $ 3,737,436 Accumulated Other Comprehensive Income (Loss) Changes in accumulated other comprehensive income (loss) by component for the six months ended June 30, 2017 and 2016 were as follows: Benefits Liability, Net of Tax Cumulative Foreign Currency Exchange, Net of Tax Net Unrealized Holding Gains (Losses) on Investments, Net of Tax Total Balances at December 31, 2016 $ 28,945 $ (150,202 ) $ (49 ) $ (121,306 ) Other comprehensive income (loss) before reclassifications 95 66,925 (164 ) 66,856 Amounts reclassified from accumulated other comprehensive loss 626 — — 626 Net other comprehensive income (loss) for the period 721 66,925 (164 ) 67,482 Balances at June 30, 2017 $ 29,666 $ (83,277 ) $ (213 ) $ (53,824 ) Benefits Liability, Net of Tax Cumulative Foreign Currency Exchange, Net of Tax Net Unrealized Holding Gains (Losses) on Investments, Net of Tax Total Balances at December 31, 2015 $ (8,607 ) $ (115,690 ) $ (4,995 ) $ (129,292 ) Other comprehensive income before reclassifications (127 ) 9,305 38,425 47,603 Amounts reclassified from accumulated other comprehensive loss (income) 433 — (845 ) (412 ) Net other comprehensive income for the period 306 9,305 37,580 47,191 Balances at June 30, 2016 $ (8,301 ) $ (106,385 ) $ 32,585 $ (82,101 ) 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 six months ended June 30, 2017 and 2016 : Details about Accumulated Other Comprehensive Income (Loss) Components Location of Reclassification (Income (Expense)) in Consolidated Statements of Operations Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Amortization of pension and other post-retirement items Net loss (1) $ (466 ) $ (369 ) $ (929 ) $ (703 ) Benefit from income taxes 140 142 303 270 (326 ) (227 ) (626 ) (433 ) Net unrealized gains on available-for-sale investments Realized gain on available-for-sale investments Other income, net — 1,267 — 1,319 Provision for income taxes — (455 ) — (474 ) — 812 — 845 Total reclassifications for the period $ (326 ) $ 585 $ (626 ) $ 412 _____________ (1) These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. For additional information, please read Note 13 (Employee Benefits) to the financial statements included in the 2016 Form 10-K.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2017
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 non-employee 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 non-employee 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 $4,465 and $2,781 for the three months ended June 30, 2017 and 2016 , respectively, and $10,768 and $5,084 for the six months ended June 30, 2017 and 2016 , respectively. Under the Merger Agreement, all outstanding Axiall restricted stock units were assumed by the Company and converted into restricted stock units in respect of the Company's common stock, with the same terms and conditions except that upon settlement the award holders will receive the greater of (1) the value of $33.00 per Axiall restricted stock unit that was converted into a restricted stock unit in respect of the Company's common stock and (2) the value of the Company's common stock. The awards are classified as liability awards for financial accounting purposes and are re-measured at each reporting date until they vest.

Derivative Instruments

Derivative Instruments	6 Months Ended
	Jun. 30, 2017
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 commodities, primarily ethane and natural gas. The Company does not use derivative instruments to engage in speculative activities. The Company had no derivative instruments that were designated as fair value hedges during the three and six months ended June 30, 2017 and 2016 . 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). The Company had non-hedge designated feedstock forward contracts for approximately 173,900,000 gallons and 9,100,000 MMBtu as of June 30, 2017 and for approximately 257,000,000 gallons and 8,500,000 MMBtu as of December 31, 2016 . Certain of the Company's derivative instruments are executed under an International Swaps and Derivatives Association ("ISDA") Master Agreement, which permits the Company and a counterparty to aggregate the amounts owed by each party under multiple transactions and replace them with a single net amount payable by one party to the other. The following tables present the Company's derivative assets and derivative liabilities reported in the consolidated balance sheets and derivative assets and derivative liabilities subject to enforceable master netting arrangements. June 30, 2017 Net Presentation Gross Presentation Net Assets (Liabilities) Presented in the Consolidated Balance Sheets Risk management assets—Commodity forward contracts Risk management liabilities—Commodity forward contracts Accounts receivable, net Derivative positions subject to enforceable master netting arrangements $ — $ — $ — Derivative positions not subject to enforceable master netting arrangements 2,245 2,245 — 2,245 2,245 — Deferred charges and other assets, net Derivative positions subject to enforceable master netting — — — Derivative positions not subject to enforceable master netting 2,273 2,273 — 2,273 2,273 — Accrued liabilities Derivative positions subject to enforceable master netting (203 ) 1,062 (1,265 ) Derivative positions not subject to enforceable master netting (940 ) — (940 ) (1,143 ) 1,062 (2,205 ) Other liabilities Derivative positions subject to enforceable master netting (1,545 ) 771 (2,316 ) Derivative positions not subject to enforceable master netting (3,109 ) — (3,109 ) (4,654 ) 771 (5,425 ) Risk management assets (liabilities)—Commodity forward contracts $ 6,351 $ (7,630 ) December 31, 2016 Net Presentation Gross Presentation Net Assets (Liabilities) Presented in the Consolidated Balance Sheets Risk management assets—Commodity forward contracts Risk management liabilities—Commodity forward contracts Accounts receivable, net Derivative positions subject to enforceable master netting $ 1,498 $ 1,636 $ (138 ) Derivative positions not subject to enforceable master netting 6,091 6,091 — 7,589 7,727 (138 ) Deferred charges and other assets, net Derivative positions subject to enforceable master netting — — — Derivative positions not subject to enforceable master netting 5,249 5,249 — 5,249 5,249 — Accrued liabilities Derivative positions subject to enforceable master netting — — — Derivative positions not subject to enforceable master netting (1,349 ) — (1,349 ) (1,349 ) — (1,349 ) Other liabilities Derivative positions subject to enforceable master netting (436 ) 2,010 (2,446 ) Derivative positions not subject to enforceable master netting (3,288 ) — (3,288 ) (3,724 ) 2,010 (5,734 ) Risk management assets (liabilities)—Commodity forward contracts $ 14,986 $ (7,221 ) 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 Hedging Instruments Location of Gain (Loss) Recognized in Income on Derivative Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Commodity forward contracts Cost of sales $ (435 ) $ 11,567 $ (9,602 ) $ 15,624 See Note 15 for the fair value of the Company's derivative instruments.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2017
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: June 30, 2017 Level 1 Level 2 Total Derivative instruments Risk management assets—Commodity forward contracts $ 567 $ 5,784 $ 6,351 Risk management liabilities—Commodity forward contracts (6,692 ) (938 ) (7,630 ) December 31, 2016 Level 1 Level 2 Total Derivative instruments Risk management assets—Commodity forward contracts $ 878 $ 14,108 $ 14,986 Risk management liabilities—Commodity forward contracts (6,854 ) (367 ) (7,221 ) The Level 2 measurements for the Company's commodity contracts are derived using forward curves supplied by industry-recognized and unrelated third-party services. There were no transfers in or out of Levels 1 and 2 of the fair value hierarchy for the six months ended June 30, 2017 and 2016 . 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 current 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, accounts payable and current term loan approximate their fair values 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 fair value of the Company's long-term debt instruments is determined using a market approach, based upon quotes from financial reporting services. 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. June 30, 2017 December 31, 2016 Carrying Value Fair Value Carrying Value Fair Value Revolving credit facility $ 140,000 $ 140,000 $ 325,000 $ 325,000 4.625% Westlake 2021 Senior Notes 648,295 649,054 651,630 650,847 4.625% Subsidiary 2021 Senior Notes 65,725 65,930 66,069 65,775 3.60% senior notes due 2022 248,280 255,255 248,109 251,725 4.875% Westlake 2023 Senior Notes 446,109 453,092 447,224 451,301 4.875% Subsidiary 2023 Senior Notes 16,705 16,923 16,747 16,501 3.60% 2026 Senior Notes 739,688 744,946 739,243 722,055 Loan related to tax-exempt waste disposal revenue bonds due 2027 10,889 10,889 10,889 10,889 6 ½% tax-exempt senior notes due 2029 99,120 113,358 99,084 112,433 6 ¾% tax-exempt senior notes due 2032 248,176 254,100 248,117 258,818 6 ½% 2035 GO Zone Senior Notes 88,183 101,589 88,161 100,323 6 ½% 2035 IKE Zone Senior Notes 64,414 74,190 64,398 73,270 5.0% 2046 Senior Notes 674,316 741,265 673,983 691,712

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The effective income tax rate was 30.0% for the second quarter of 2017 . The effective income tax rate for the second quarter of 2017 was below the U.S. federal statutory rate of 35.0% primarily due to a higher domestic manufacturing deduction, depletion deductions, income attributable to noncontrolling interests, research and development credits and the foreign earnings rate differential, partially offset by state income taxes. The effective income tax rate was 36.5% for the three months ended June 30, 2016. The effective income tax rate for the second quarter of 2016 was above the U.S. federal statutory rate of 35.0% primarily due to state income taxes, partially offset by the domestic manufacturing deduction and income attributable to noncontrolling interests. The effective income tax rate was 29.0% for the six months ended June 30, 2017. The effective income tax rate for the six months ended June 30, 2017 was below the U.S. federal statutory rate of 35.0% primarily due to certain discrete adjustments, a higher domestic manufacturing deduction, depletion deductions, income attributable to noncontrolling interests, research and development credits and the foreign earnings rate differential, partially offset by state income taxes. The effective income tax rate was 35.7% for the six months ended June 30, 2016. The effective income tax rate for the six months ended June 30, 2016 was above the U.S. federal statutory rate of 35.0% primarily due to state income taxes, partially offset by the domestic manufacturing deduction, income attributable to noncontrolling interests and the foreign earnings rate differential. The Company files income tax returns in the U.S. federal jurisdiction and in various states and foreign jurisdictions. During the second quarter of 2017, the Internal Revenue Service began an audit of the Company for the tax years 2012 to 2014.

Earnings per Share

Earnings per Share	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share The Company has unvested shares of 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 June 30, Six Months Ended June 30, 2017 2016 2017 2016 Net income attributable to Westlake Chemical Corporation $ 152,827 $ 111,124 $ 291,017 $ 234,252 Less: Net income attributable to participating securities (819 ) (504 ) (1,513 ) (1,054 ) Net income attributable to common shareholders $ 152,008 $ 110,620 $ 289,504 $ 233,198 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 June 30, Six Months Ended June 30, 2017 2016 2017 2016 Weighted average common shares—basic 129,051,227 129,583,224 129,015,507 129,886,594 Plus incremental shares from: Assumed exercise of options 735,487 397,303 724,136 403,927 Weighted average common shares—diluted 129,786,714 129,980,527 129,739,643 130,290,521 Earnings per common share attributable to Westlake Chemical Corporation: Basic $ 1.18 $ 0.85 $ 2.24 $ 1.80 Diluted $ 1.17 $ 0.85 $ 2.23 $ 1.79 Excluded from the computation of diluted earnings per share are options to purchase 583,585 and 695,040 shares of common stock for the three months ended June 30, 2017 and 2016 , respectively, and 511,085 and 625,494 shares of common stock for the six months ended June 30, 2017 and 2016 , respectively. These options were outstanding during the periods reported but were excluded because the effect of including them would have been antidilutive.

Supplemental Information

Supplemental Information	6 Months Ended
	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Information	Supplemental Information Accrued Liabilities Accrued liabilities were $447,412 and $537,483 at June 30, 2017 and December 31, 2016 , respectively. Accrued rebates, which are a component of accrued liabilities, were $84,088 and $77,985 at June 30, 2017 and December 31, 2016 , respectively. No other component of accrued liabilities was more than five percent of total current liabilities. Accrued liabilities with affiliates were $11,203 and $10,551 at June 30, 2017 and December 31, 2016 , respectively. Non-cash Investing Activity The change in capital expenditure accrual increasing additions to property, plant and equipment was $10,848 for the six months ended June 30, 2017 . The change in capital expenditure accrual reducing additions to property, plant and equipment was $50,326 for the six months ended June 30, 2016 .

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company is involved in a number of legal and regulatory matters, principally environmental in nature, that are incidental to the normal conduct of its business, including lawsuits, investigations and claims. The outcome of these matters are inherently unpredictable. The Company believes that, in the aggregate, the outcome of all known legal and regulatory matters will not have a material adverse effect on its consolidated financial statements; however, specific outcomes with respect to such matters may be material to the Company's consolidated statements of operations in any particular period in which costs, if any, are recognized. The Company's assessment of the potential impact of environmental matters, in particular, is subject to uncertainty due to the complex, ongoing and evolving process of investigation and remediation of such environmental matters, and the potential for technological and regulatory developments. In addition, the impact of evolving claims and programs, such as natural resource damage claims, industrial site reuse initiatives and state remediation programs creates further uncertainty of the ultimate resolution of these matters. The Company anticipates that the resolution of many legal and regulatory matters, and in particular environmental matters, will occur over an extended period of time. Environmental. As of June 30, 2017 and December 31, 2016 , the Company had reserves for environmental contingencies totaling approximately $47,669 and $48,817 , respectively, most of which was classified as noncurrent liabilities. The Company's assessment of the potential impact of these environmental contingencies is subject to considerable uncertainty due to the complex, ongoing and evolving process of investigation and remediation, if necessary, of such environmental contingencies, and the potential for technological and regulatory developments. From time to time the Company receives notices or inquiries from government entities regarding alleged violations of environmental laws and regulations pertaining to, among other things, the disposal, emission and storage of chemical substances, including hazardous wastes. Item 103 of the SEC's Regulation S-K requires disclosure of certain environmental matters when a governmental authority is a party to the proceedings and the proceedings involve potential monetary sanctions, unless the Company reasonably believes such sanctions would not exceed $100. • In May 2013, an amendment to an existing consent order agreed to by the West Virginia Department of Environmental Protection and a predecessor of Axiall required that it, among other things, pay a penalty in the amount of $449 and continue certain corrective action associated with discharges of hexachlorocyclohexane (commonly referred to as BHC) from the Natrium, West Virginia facility's effluent discharge outfalls. The penalty was paid and corrective actions required are on-going per a December 2016 agreement to extend the compliance date under the amended consent order. • In May 2013 and September 2013, the Environmental Protection Agency (the "EPA") conducted inspections at the Company's Plaquemine, Louisiana facility pursuant to requirements of the federal Clean Air Act Section 112(r) Risk Management Program and Title V. As a result of the inspections, the EPA identified areas of concern and the Company subsequently engaged in negotiations to resolve alleged violations. A Consent Agreement and Final Order (“CAFO”) was filed in October 2016, pursuant to which the Company paid civil penalties in the amount of $167 . • The LDEQ has issued notices of violations ("NOVs") regarding the Company's olefins facilities in Lake Charles, Louisiana for various air and water compliance issues. The Company has reached an agreement with the LDEQ to settle certain of the NOVs along with other alleged violations not made the subject of any specific NOV in two separate settlement agreements for a combined $192 in civil penalties. The penalties have been paid and upon submission of a letter withdrawing Westlake's request for administrative hearing, this matter is expected to be resolved. • During September 2010, the Company's vinyls facilities in north Lake Charles and Plaquemine each received a Consolidated Compliance Order and Notice of Potential Penalty, alleging violations of various requirements of those facilities' air permits, based largely on self-reported permit deviations related to record-keeping violations. The Company has been negotiating a possible global settlement of these and several other matters with the LDEQ. The Company believes the resolution of these matters may require the payment of a monetary sanction in excess of $100 . • In April 2015, Axiall received a communication from the EPA related to, among other things, the EPA's investigation of the 2012 and 2013 fires that occurred at its VCM plant in Lake Charles. In late 2015, Axiall settled this matter with the EPA, with such settlement including on-going supplemental environmental projects and a penalty payment of $878 . • For several years, the EPA has been conducting an enforcement initiative against petroleum refineries and petrochemical plants with respect to emissions from flares. On April 21, 2014, the Company received a Clean Air Act Section 114 Information Request from the EPA which sought information regarding flares at the Calvert City, Kentucky and certain Lake Charles facilities. The EPA has informed the Company that the information provided leads the EPA to believe that some of the flares are out of compliance with applicable standards. The EPA has indicated that it is seeking a consent decree that would obligate the Company to take corrective actions relating to the alleged noncompliance. The Company believes the resolution of these matters may require the payment of a monetary sanction in excess of $100 . The Company does not believe that resolutions of any or all of these matters will have a material adverse effect on the Company's financial condition, results of operations or cash flows. Environmental Remediation: Reasonably Possible Matters. The Company's assessment of the potential impact of environmental contingencies is subject to considerable uncertainty due to the complex, ongoing and evolving process of investigation and remediation, if necessary, of such environmental contingencies, and the potential for technological and regulatory developments. As such, in addition to the amounts currently reserved, the Company may be subject to reasonably possible loss contingencies related to environmental matters in the range of $40,000 to $80,000 .

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2017
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 June 30, Six Months Ended June 30, 2017 2016 2017 2016 Net external sales Olefins Polyethylene $ 358,392 $ 371,658 $ 744,334 $ 717,690 Styrene, feedstock and other 130,842 122,826 287,895 207,814 Total Olefins 489,234 494,484 1,032,229 925,504 Vinyls PVC, caustic soda and other 1,157,317 462,472 2,288,446 893,374 Building products 332,610 129,105 601,102 242,370 Total Vinyls 1,489,927 591,577 2,889,548 1,135,744 $ 1,979,161 $ 1,086,061 $ 3,921,777 $ 2,061,248 Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Intersegment sales Olefins $ 97,992 $ 27,293 $ 183,936 $ 55,242 Vinyls 319 225 611 589 $ 98,311 $ 27,518 $ 184,547 $ 55,831 Income (loss) from operations Olefins $ 143,277 $ 140,564 $ 323,095 $ 289,799 Vinyls 143,320 52,208 214,761 114,324 Corporate and other (19,481 ) (12,834 ) (35,442 ) (21,909 ) $ 267,116 $ 179,938 $ 502,414 $ 382,214 Depreciation and amortization Olefins $ 35,175 $ 30,236 $ 76,215 $ 58,933 Vinyls 106,822 36,268 214,095 72,555 Corporate and other 2,633 746 4,589 1,476 $ 144,630 $ 67,250 $ 294,899 $ 132,964 Other income (expense), net Olefins $ 588 $ 1,093 $ 1,738 $ 2,606 Vinyls (1,534 ) 4,466 2,058 2,949 Corporate and other 408 2,622 737 5,271 $ (538 ) $ 8,181 $ 4,533 $ 10,826 Provision for (benefit from) income taxes Olefins $ 36,453 $ 51,940 $ 94,264 $ 104,473 Vinyls 39,237 16,297 54,195 33,567 Corporate and other (7,502 ) (1,653 ) (24,388 ) (2,156 ) $ 68,188 $ 66,584 $ 124,071 $ 135,884 Capital expenditures Olefins $ 23,733 $ 93,739 $ 49,083 $ 188,890 Vinyls 114,372 56,613 222,454 96,869 Corporate and other 8,512 481 9,365 1,401 $ 146,617 $ 150,833 $ 280,902 $ 287,160 A reconciliation of total segment income from operations to consolidated income before income taxes is as follows: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Income from operations $ 267,116 $ 179,938 $ 502,414 $ 382,214 Interest expense (38,972 ) (5,915 ) (78,748 ) (12,600 ) Other income (expense), net (538 ) 8,181 4,533 10,826 Income before income taxes $ 227,606 $ 182,204 $ 428,199 $ 380,440 June 30, December 31, Total assets Olefins $ 2,077,986 $ 2,092,617 Vinyls 8,379,465 8,287,204 Corporate and other 428,256 510,432 $ 10,885,707 $ 10,890,253

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2017
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	6 Months Ended
	Jun. 30, 2017
Guarantees [Abstract]
Guarantor Disclosures	Guarantor Disclosures The Company's payment obligations under the 3.60% senior notes due 2022 , the 3.60% 2026 Senior Notes, the 5.0% 2046 Senior Notes, 4.625% Westlake 2021 Senior Notes and the 4.875% Westlake 2023 Senior Notes are fully and unconditionally guaranteed by each of its current and future domestic subsidiaries that guarantee other debt of the Company or of another guarantor of those notes in excess of $5,000 (the "Guarantor Subsidiaries"). Each Guarantor Subsidiary is 100% owned by Westlake Chemical Corporation (the " 100% Owned Guarantor Subsidiaries"). In October 2016, the Company executed a Joinder Agreement with the Administrative Agent of the Credit Agreement, whereby certain subsidiaries of the Company were added as Guarantor Subsidiaries. These guarantees are the joint and several obligations of the Guarantor Subsidiaries. The following unaudited condensed consolidating financial information presents the financial condition, results of operations and cash flows of Westlake Chemical Corporation, the 100% owned Guarantor Subsidiaries, and the remaining subsidiaries that do not guarantee the 3.60% senior notes due 2022 , the 3.60% 2026 Senior Notes, the 5.0% 2046 Senior Notes, 4.625% Westlake 2021 Senior Notes and the 4.875% Westlake 2023 Senior Notes (the "Non-Guarantor Subsidiaries"), together with consolidating eliminations necessary to present the Company's results on a consolidated basis. In August 2016, certain of the Company's subsidiary guarantors were released from their guarantees of the Company's 3.60% senior notes due 2022 in connection with the replacement of the Company's revolving credit facility. Westlake Chemical OpCo LP, which was previously separately presented as a less than 100% owned guarantor, and certain of the Company's other 100% owned subsidiaries that were previously presented as guarantors, are now reflected as Non-Guarantor Subsidiaries in the condensed consolidating guarantor financial information. Prior periods were retrospectively adjusted to conform to the current presentation of Guarantor Subsidiaries and Non-Guarantor Subsidiaries. Condensed Consolidating Financial Information as of June 30, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Balance Sheet Current assets Cash and cash equivalents $ 49,366 $ 15,399 $ 331,011 $ — $ 395,776 Accounts receivable, net 2,742,556 3,785,141 364,318 (5,796,207 ) 1,095,808 Inventories — 631,802 199,898 — 831,700 Prepaid expenses and other current assets 75,730 40,213 9,349 (79,548 ) 45,744 Restricted cash — 1,500 7,107 — 8,607 Total current assets 2,867,652 4,474,055 911,683 (5,875,755 ) 2,377,635 Property, plant and equipment, net — 4,326,202 1,990,529 — 6,316,731 Other assets, net Goodwill — 847,816 151,798 — 999,614 Customer relationships, net — 509,933 144,159 — 654,092 Other intangible assets, net — 97,224 72,767 — 169,991 Deferred charges and other assets, net 9,552,799 790,393 1,540,773 (11,516,321 ) 367,644 Total other assets, net 9,552,799 2,245,366 1,909,497 (11,516,321 ) 2,191,341 Total assets $ 12,420,451 $ 11,045,623 $ 4,811,709 $ (17,392,076 ) $ 10,885,707 Current liabilities Accounts payable $ 5,183,033 $ 815,642 $ 343,531 $ (5,758,697 ) $ 583,509 Accrued liabilities — 355,132 209,338 (117,058 ) 447,412 Total current liabilities 5,183,033 1,170,774 552,869 (5,875,755 ) 1,030,921 Long-term debt, net 3,396,581 4,537,551 421,405 (4,865,637 ) 3,489,900 Deferred income taxes — 1,573,733 97,781 (22,985 ) 1,648,529 Pension and other liabilities — 365,170 142,144 — 507,314 Total liabilities 8,579,614 7,647,228 1,214,199 (10,764,377 ) 6,676,664 Total Westlake Chemical Corporation stockholders' equity 3,840,837 3,398,395 3,229,304 (6,627,699 ) 3,840,837 Noncontrolling interests — — 368,206 — 368,206 Total equity 3,840,837 3,398,395 3,597,510 (6,627,699 ) 4,209,043 Total liabilities and equity $ 12,420,451 $ 11,045,623 $ 4,811,709 $ (17,392,076 ) $ 10,885,707 Condensed Consolidating Financial Information as of December 31, 2016 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Balance Sheet Current assets Cash and cash equivalents $ 146,990 $ 53,006 $ 259,457 $ — $ 459,453 Accounts receivable, net 2,117,540 3,329,871 323,931 (4,832,599 ) 938,743 Inventories — 597,819 203,281 — 801,100 Prepaid expenses and other current assets 30,748 41,755 12,494 (36,504 ) 48,493 Restricted cash — — 160,527 — 160,527 Total current assets 2,295,278 4,022,451 959,690 (4,869,103 ) 2,408,316 Property, plant and equipment, net — 4,475,943 1,944,119 — 6,420,062 Other assets, net Goodwill — 791,706 154,847 — 946,553 Customer relationships, net — 468,645 142,970 — 611,615 Other intangible assets, net — 130,243 71,177 (25,581 ) 175,839 Deferred charges and other assets, net 9,170,042 874,003 1,115,877 (10,832,054 ) 327,868 Total other assets, net 9,170,042 2,264,597 1,484,871 (10,857,635 ) 2,061,875 Total assets $ 11,465,320 $ 10,762,991 $ 4,388,680 $ (15,726,738 ) $ 10,890,253 Current liabilities Accounts payable $ 4,330,375 $ 748,364 $ 225,300 $ (4,807,780 ) $ 496,259 Accrued liabilities 26,367 389,216 183,223 (61,323 ) 537,483 Term loan — — 149,341 — 149,341 Total current liabilities 4,356,742 1,137,580 557,864 (4,869,103 ) 1,183,083 Long-term debt, net 3,584,949 4,090,775 — (3,997,070 ) 3,678,654 Deferred income taxes — 1,581,260 91,809 (22,494 ) 1,650,575 Pension and other liabilities — 360,622 125,274 — 485,896 Total liabilities 7,941,691 7,170,237 774,947 (8,888,667 ) 6,998,208 Total Westlake Chemical Corporation stockholders' equity 3,523,629 3,592,754 3,245,317 (6,838,071 ) 3,523,629 Noncontrolling interests — — 368,416 — 368,416 Total equity 3,523,629 3,592,754 3,613,733 (6,838,071 ) 3,892,045 Total liabilities and equity $ 11,465,320 $ 10,762,991 $ 4,388,680 $ (15,726,738 ) $ 10,890,253 Condensed Consolidating Financial Information for the Three Months Ended June 30, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Operations Net sales $ — $ 1,596,952 $ 804,002 $ (421,793 ) $ 1,979,161 Cost of sales — 1,346,983 641,349 (415,005 ) 1,573,327 Gross profit — 249,969 162,653 (6,788 ) 405,834 Selling, general and administrative expenses 142 95,845 41,427 (6,788 ) 130,626 Transaction and integration-related costs — 8,092 — — 8,092 Income (loss) from operations (142 ) 146,032 121,226 — 267,116 Other income (expense) Interest expense (38,160 ) (45,783 ) (34 ) 45,005 (38,972 ) Other income (expense), net 37,282 3,550 3,635 (45,005 ) (538 ) Income (loss) before income taxes (1,020 ) 103,799 124,827 — 227,606 Provision for (benefit from) income taxes 4,616 52,083 11,489 — 68,188 Equity in net income of subsidiaries 158,463 — — (158,463 ) — Net income 152,827 51,716 113,338 (158,463 ) 159,418 Net income attributable to noncontrolling interests — — 6,591 — 6,591 Net income attributable to Westlake Chemical Corporation $ 152,827 $ 51,716 $ 106,747 $ (158,463 ) $ 152,827 Comprehensive income attributable to Westlake Chemical Corporation $ 203,090 $ 51,776 $ 148,417 $ (200,193 ) $ 203,090 Condensed Consolidating Financial Information for the Three Months Ended June 30, 2016 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Operations Net sales $ — $ 820,190 $ 553,173 $ (287,302 ) $ 1,086,061 Cost of sales — 698,096 428,898 (282,299 ) 844,695 Gross profit — 122,094 124,275 (5,003 ) 241,366 Selling, general and administrative expenses 950 44,020 21,461 (5,003 ) 61,428 Income (loss) from operations (950 ) 78,074 102,814 — 179,938 Other income (expense) Interest expense (11,151 ) (5,686 ) (205 ) 11,127 (5,915 ) Other income (expense), net 4,050 (1,183 ) 16,441 (11,127 ) 8,181 Income (loss) before income taxes (8,051 ) 71,205 119,050 — 182,204 Provision for (benefit from) income taxes (2,960 ) 55,671 13,873 — 66,584 Equity in net income of subsidiaries 116,215 — — (116,215 ) — Net income 111,124 15,534 105,177 (116,215 ) 115,620 Net income attributable to noncontrolling interests — — 4,496 — 4,496 Net income attributable to Westlake Chemical Corporation $ 111,124 $ 15,534 $ 100,681 $ (116,215 ) $ 111,124 Comprehensive income attributable to Westlake Chemical Corporation $ 119,686 $ 15,634 $ 102,296 $ (117,930 ) $ 119,686 Condensed Consolidating Financial Information for the Six Months Ended June 30, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Operations Net sales $ — $ 3,176,677 $ 1,540,087 $ (794,987 ) $ 3,921,777 Cost of sales — 2,706,258 1,224,009 (781,467 ) 3,148,800 Gross profit — 470,419 316,078 (13,520 ) 772,977 Selling, general and administrative expenses 919 188,109 78,769 (13,520 ) 254,277 Transaction and integration-related costs — 16,224 62 — 16,286 Income (loss) from operations (919 ) 266,086 237,247 — 502,414 Other income (expense) Interest expense (76,345 ) (91,460 ) (840 ) 89,897 (78,748 ) Other income (expense), net 74,439 3,293 16,698 (89,897 ) 4,533 Income (loss) before income taxes (2,825 ) 177,919 253,105 — 428,199 Provision for (benefit from) income taxes (851 ) 105,455 19,467 — 124,071 Equity in net income of subsidiaries 292,991 — — (292,991 ) — Net income 291,017 72,464 233,638 (292,991 ) 304,128 Net income attributable to noncontrolling interests — — 13,111 — 13,111 Net income attributable to Westlake Chemical Corporation $ 291,017 $ 72,464 $ 220,527 $ (292,991 ) $ 291,017 Comprehensive income attributable to Westlake Chemical Corporation $ 355,787 $ 72,449 $ 259,034 $ (331,483 ) $ 355,787 Condensed Consolidating Financial Information for the Six Months Ended June 30, 2016 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Operations Net sales $ — $ 1,581,931 $ 1,122,992 $ (643,675 ) $ 2,061,248 Cost of sales — 1,340,833 856,668 (633,204 ) 1,564,297 Gross profit — 241,098 266,324 (10,471 ) 496,951 Selling, general and administrative expenses 1,557 81,017 42,634 (10,471 ) 114,737 Income (loss) from operations (1,557 ) 160,081 223,690 — 382,214 Other income (expense) Interest expense (21,563 ) (12,471 ) (459 ) 21,893 (12,600 ) Other income (expense), net 5,865 (75 ) 26,929 (21,893 ) 10,826 Income (loss) before income taxes (17,255 ) 147,535 250,160 — 380,440 Provision for (benefit from) income taxes (6,182 ) 117,874 24,192 — 135,884 Equity in net income of subsidiaries 245,325 — — (245,325 ) — Net income 234,252 29,661 225,968 (245,325 ) 244,556 Net income attributable to noncontrolling interests — — 10,304 — 10,304 Net income attributable to Westlake Chemical Corporation $ 234,252 $ 29,661 $ 215,664 $ (245,325 ) $ 234,252 Comprehensive income attributable to Westlake Chemical Corporation $ 281,443 $ 29,967 $ 254,514 $ (284,481 ) $ 281,443 Condensed Consolidating Financial Information for the Six Months Ended June 30, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Cash Flows Cash flows from operating activities Net income $ 291,017 $ 72,464 $ 233,638 $ (292,991 ) $ 304,128 Adjustments to reconcile net income to net cash provided by (used for) operating activities Depreciation and amortization — 193,594 101,305 — 294,899 Deferred income taxes (126 ) 15,207 (119 ) — 14,962 Net changes in working capital and other (400,511 ) (25,601 ) (1,154 ) 292,991 (134,275 ) Net cash provided by (used for) operating activities (109,620 ) 255,664 333,670 — 479,714 Cash flows from investing activities Additions to property, plant and equipment — (198,621 ) (82,281 ) — (280,902 ) Additions to cost method investment — (31,000 ) — — (31,000 ) Proceeds from disposition of assets — 3 130 — 133 Proceeds from involuntary conversion of assets — 1,672 — — 1,672 Settlements of derivative instruments — (376 ) — — (376 ) Net cash used for investing activities — (228,322 ) (82,151 ) — (310,473 ) Cash flows from financing activities Intercompany financing 241,210 (253,075 ) 11,865 — — Dividends paid (49,315 ) — — — (49,315 ) Distributions to noncontrolling interests — 188,646 (204,679 ) — (16,033 ) Proceeds from issuance of notes payable — — 3,544 — 3,544 Proceeds from drawdown of revolver 175,000 — — — 175,000 Restricted cash associated with term loan 154,000 — — — 154,000 Repayment of term loan (150,000 ) — — — (150,000 ) Repayment of notes payable — (520 ) (4,381 ) — (4,901 ) Repayment of revolver (360,000 ) — — — (360,000 ) Other, net 1,101 — — — 1,101 Net cash provided by (used for) financing activities 11,996 (64,949 ) (193,651 ) — (246,604 ) Effect of exchange rate changes on cash and cash equivalents — — 13,686 — 13,686 Net increase (decrease) in cash and cash equivalents (97,624 ) (37,607 ) 71,554 — (63,677 ) Cash and cash equivalents at beginning of period 146,990 53,006 259,457 — 459,453 Cash and cash equivalents at end of period $ 49,366 $ 15,399 $ 331,011 $ — $ 395,776 Condensed Consolidating Financial Information for the Six Months Ended June 30, 2016 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Cash Flows Cash flows from operating activities Net income $ 234,252 $ 29,661 $ 225,968 $ (245,325 ) $ 244,556 Adjustments to reconcile net income to net cash provided by operating activities Depreciation and amortization — 66,137 66,827 — 132,964 Deferred income taxes (4,802 ) 96,990 10,802 — 102,990 Net changes in working capital and other (274,585 ) (38,234 ) (43,124 ) 245,325 (110,618 ) Net cash provided by (used for) operating activities (45,135 ) 154,554 260,473 — 369,892 Cash flows from investing activities Additions to property, plant and equipment — (94,775 ) (192,385 ) — (287,160 ) Proceeds from disposition of assets — 7 98 — 105 Proceeds from sales and maturities of securities 302,432 — — — 302,432 Purchase of securities (130,830 ) (7,592 ) — — (138,422 ) Settlements of derivative instruments — (3,372 ) — — (3,372 ) Net cash provided by (used for) investing activities 171,602 (105,732 ) (192,287 ) — (126,417 ) Cash flows from financing activities Intercompany financing 106,904 (212,948 ) 106,044 — — Debt issuance costs (9,700 ) — — — (9,700 ) Dividends paid (47,317 ) — — — (47,317 ) Distributions to noncontrolling interests — 158,392 (166,476 ) — (8,084 ) Proceeds from issuance of notes payable — — 3,842 — 3,842 Repayment of notes payable — — (8,626 ) — (8,626 ) Repurchase of common stock for treasury (67,404 ) — — — (67,404 ) Other 800 — — — 800 Net cash used for financing activities (16,717 ) (54,556 ) (65,216 ) — (136,489 ) Effect of exchange rate changes on cash and cash equivalents — — 1,486 1,486 Net increase (decrease) in cash and cash equivalents 109,750 (5,734 ) 4,456 — 108,472 Cash and cash equivalents at beginning of period 303,131 6,818 352,576 — 662,525 Cash and cash equivalents at end of period $ 412,881 $ 1,084 $ 357,032 $ — $ 770,997

Basis of Financial Statements (

Basis of Financial Statements (Policies)	6 Months Ended
	Jun. 30, 2017
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, 2016 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, 2016 (the " 2016 Form 10-K"), filed with the SEC on February 22, 2017 . 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, 2016 . 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 June 30, 2017 , its results of operations for the three and six months ended June 30, 2017 and 2016 and the changes in its cash position for the six months ended June 30, 2017 and 2016 . 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, 2017 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.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Revenue from Contracts with Customers (ASU No. 2014-09) 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. In 2016, the FASB issued various additional authoritative guidance for the new revenue recognition standard. The accounting standard will be effective for reporting periods beginning after December 15, 2017. The Company is in the process of evaluating the impact that the new accounting standard will have on its consolidated financial position, results of operations and cash flows. The Company has completed a preliminary assessment including detailed review of a representative sample of contracts with customers. The Company does not believe that adoption of the new accounting standard will significantly impact timing or amounts of revenue recognized for the majority of its sales. The Company intends to elect the modified retrospective method of adoption. Recognition and Measurement of Financial Assets and Financial Liabilities (ASU No. 2016-01) In January 2016, the FASB issued an accounting standards update making certain changes principally to the current guidance for equity investments, financial liabilities under the fair value option and the presentation and disclosure requirements for financial instruments. Among other things, the guidance (1) requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value, with changes in fair value recognized in net income; (2) provide entities with a policy election to record equity investments without readily determinable fair values at cost, less impairment, and subsequent adjustments for observable price changes (changes in the basis of these equity investments to be reported in net income); (3) requires an entity that has elected the fair value option for financial liabilities to recognize changes in fair value due to instrument-specific credit risk separately in other comprehensive income; (4) clarified current guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale debt securities; and (5) requires specific disclosure pertaining to financial assets and financial liabilities in the financial statements. The accounting standard will be effective for reporting periods beginning after December 15, 2017. 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. Leases (ASU No. 2016-02) In February 2016, the FASB issued an accounting standards update on a new lease standard that will supersede the existing lease guidance. The standard requires a lessee to recognize assets and liabilities related to long-term leases that are classified as operating leases under current guidance on its balance sheet. An asset would be recognized related to the right to use the underlying asset and a liability would be recognized related to the obligation to make lease payments over the term of the lease. The standard also requires expanded disclosures related to leases. The accounting standard will be effective for reporting periods beginning after December 15, 2018. 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. Credit Losses (ASU No. 2016-13) In June 2016, the FASB issued an accounting standards update providing new guidance for the accounting for credit losses on loans and other financial instruments. The new guidance introduces an approach based on expected losses to estimate credit losses on certain types of financial instruments. The standard also modifies the impairment model for available-for-sale debt securities and provides for a simplified accounting model for purchased financial assets with credit deterioration since their origination. The accounting standard will be effective for reporting periods beginning after December 15, 2019 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Cash Flows (ASU No. 2016-15) In August 2016, the FASB issued an accounting standards update providing new guidance on the classification of certain cash receipts and payments including debt extinguishment costs, debt prepayment costs, settlement of zero-coupon debt instruments, contingent consideration payments, proceeds from the settlement of insurance claims and life insurance policies and distributions received from equity method investees in the statement of cash flows. This update is required to be applied using the retrospective transition method to each period presented unless it is impracticable to be applied retrospectively. In such situation, this guidance is to be applied prospectively. The accounting standard will be effective for reporting periods beginning after December 15, 2017 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Cash Flows (ASU No. 2016-18) In November 2016, the FASB issued an accounting standards update to clarify certain existing principles in Accounting Standards Codification ("ASC") 230, Cash flows, including providing additional guidance related to transfers between cash and restricted cash and how entities present, in their statement of cash flows, the cash receipts and cash payments that directly affect the restricted cash accounts. The accounting standard will be effective for reporting periods beginning after December 15, 2017. Upon adoption of the accounting standards update, the Company will retrospectively adjust its financial statements to reflect restricted cash in the beginning and ending cash and restricted cash balances within the statements of cash flows. Transfers between cash and restricted cash will be excluded from net changes in cash and cash equivalents within the statements of cash flows. Business Combinations (ASU No. 2017-01) In January 2017, the FASB issued an accounting standards update to assist entities with evaluating when a set of transferred assets and activities is a business. The guidance requires an entity to evaluate if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets; if so, the set of transferred assets and activities is not a business. The guidance also requires a business to include at least one substantive process and narrows the definition of outputs by more closely aligning it with how outputs are described in the ASC 606, Revenue from contracts with customers. The accounting standard will be effective for reporting periods beginning after December 15, 2017 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Intangibles - Goodwill and Other (ASU No. 2017-04) In January 2017, the FASB issued an accounting standards update to simplify the subsequent measurement of goodwill. The guidance removes Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. A goodwill impairment will now be the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The accounting standard will be effective for reporting periods beginning after December 15, 2019 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (ASU No. 2017-05) In February 2017, the FASB issued an accounting standards update to clarify the scope of guidance related to other income — gains and losses from the derecognition of nonfinancial assets, and to add guidance for partial sales of nonfinancial assets. The new guidance clarifies that an in substance nonfinancial asset is an asset or group of assets for which substantially all of the fair value consists of nonfinancial assets and the group or subsidiary is not a business. The guidance also outlines that when an entity transfers its controlling interest in a nonfinancial asset, but retains a noncontrolling interest, it will measure the retained interest at fair value resulting in full gain or loss recognition upon sale of the controlling interest. The accounting standard will be effective for reporting periods beginning after December 15, 2017 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Compensation - Retirement Benefits (ASU No. 2017-07) In March 2017, the FASB issued an accounting standards update to improve the presentation of net periodic pension cost and net periodic postretirement benefit cost. The new guidance requires employers to disaggregate the service cost component from the other components of net periodic benefit cost and report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The amendments also allow only the service cost component to be eligible for capitalization when applicable. The accounting standard will be effective for reporting periods beginning after December 15, 2017. 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. Compensation - Stock Compensation (ASU No. 2017-09) In May 2017, the FASB issued the accounting standards update to provide clarity and reduce both (1) diversity in practice and (2) cost and complexity when applying the guidance in Topic 718, Compensation-Stock Compensation, to a change to the terms or conditions of a share-based payment award. The amendments in this update provide guidance about which changes to the terms or conditions of a share-based payment award require the application of modification accounting in Topic 718. Essentially, an entity will not have to account for the effects of a modification if: (1) the fair value of the modified award is the same immediately before and after the modification; (2) the vesting conditions of the modified award are the same immediately before and after the modification; and (3) the classification of the modified award as either an equity instrument or liability instrument is the same immediately before and after the modification. This update is to be applied prospectively to an award modified on or after the adoption date. The accounting standard will be effective for reporting periods beginning after December 15, 2017. Early adoption is permitted. 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. Recently Adopted Accounting Standards Investments - Equity Method and Joint Ventures (ASU No. 2016-07) In March 2016, the FASB issued an accounting standards update providing new guidance for the accounting for equity method investments. The new guidance eliminates the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. In addition, the guidance requires that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor's previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. Therefore, upon qualifying for the equity method of accounting, no retroactive adjustment of the investment is required. The accounting standard became effective for reporting periods beginning after December 15, 2016. The Company adopted this accounting standard effective January 1, 2017 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Stock Compensation (ASU No. 2016-09) In March 2016, the FASB issued an accounting standards update to simplify several aspects of the accounting for share-based payment transactions, including income tax consequences, classifications of awards as either equity or liabilities and certain related classifications on the statement of cash flows. In addition, the new guidance permits entities to make an accounting policy election for the impact of forfeitures on the recognition of expense for share-based payment awards. Forfeitures can be estimated, as required prior to adoption of the accounting standards update, or recognized when they occur. The accounting standard became effective for reporting periods beginning after December 15, 2016. The Company adopted this accounting standard effective January 1, 2017 and elected to continue estimating forfeitures as required prior to adoption of the accounting standards update. The adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Amendments to the Consolidation Analysis (ASU No. 2016-17) In October 2016, the FASB issued an accounting standards update making certain changes to the current consolidation guidance. The amendments affect reporting entities that are required to evaluate whether they should consolidate a variable interest entity in certain situations involving entities under common control. Specifically, the amendments change the evaluation of whether a reporting entity is the primary beneficiary of a variable interest entity by changing how a reporting entity that is a single decision maker of a variable interest entity treats indirect interests in the entity held through related parties that are under common control with the reporting entity. The amendments became effective for annual periods beginning after December 15, 2016. The Company adopted this accounting standard, to be applied prospectively, effective January 1, 2017, and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows.

Acquisition (Tables)

Acquisition (Tables)	6 Months Ended
	Jun. 30, 2017
Business Combinations [Abstract]
Schedule of Business Acquisitions	The following table summarizes the consideration transferred and the estimated fair value of identified assets acquired and liabilities assumed at the date of acquisition. The preliminary allocation of the consideration transferred is based on management's estimates, judgments and assumptions. When determining the fair values of assets acquired, liabilities assumed and noncontrolling interests of the acquiree, management made significant 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 consideration paid exceeded the fair value of the net assets acquired. Therefore, goodwill of $934,715 was recorded. The goodwill recognized is primarily attributable to synergies related to the Company's vinyls integration strategy that are expected to arise from the Merger. All of the goodwill is assigned to the Company's Vinyls segment. As a portion of the goodwill arising from the Merger is attributable to foreign operations, there will be a continuing foreign currency impact to goodwill in the financial statements. Final Purchase Consideration as of August 31, 2016 Closing stock purchase: Offer per share $ 33.00 Multiplied by number of shares outstanding at acquisition 67,277 Fair value of Axiall shares outstanding purchased by the Company 2,220,141 Plus: Axiall debt repaid at acquisition 247,135 Seller's transaction costs paid by the Company (1) 47,458 Total fair value of consideration transferred 2,514,734 Fair value of Axiall share-based awards attributed to pre-combination service (2) 11,346 Additional settlement value of shares acquired 13,280 Purchase consideration 2,539,360 Fair value of previously held equity interest in Axiall (3) 102,300 Total fair value allocated to net assets acquired $ 2,641,660 _____________ (1) Transaction costs incurred by the seller included legal and advisory costs incurred for the benefit of Axiall's former shareholders and board of directors to evaluate the Company's initial Merger proposals, explore strategic alternatives and negotiate the purchase price. (2) The fair value of share-based awards attributable to pre-combination service includes the ratio of the pre-combination service performed to the original service period of the Axiall restricted share units and options, including related dividend equivalent rights. (3) Prior to the Merger, the Company owned 3.1 million shares in Axiall. The investment in Axiall was carried at estimated fair value with unrealized gains recorded as a component of accumulated other comprehensive loss in the consolidated balance sheet. The Company recognized a $49,080 gain for the investment in other income, net in the consolidated statements of operations upon gaining control.
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The information below represents the preliminary purchase price allocation: Net Assets Acquired as of August 31, 2016 Cash $ 88,251 Accounts receivable (1) 422,274 Income tax receivable 50,980 Inventories (2) 349,205 Prepaid expenses and other current assets 55,462 Property, plant and equipment (2) 2,946,442 Customer relationships (weighted average lives of 9.8 years) (3) 670,000 Other intangible assets: Trade name (weighted average lives of 6.8 years) 50,000 Technology (weighted average lives of 5.4 years) 41,500 Supply contracts and leases (weighted average lives of 6.3 years) 27,288 Other assets 95,872 Total assets acquired 4,797,274 Accounts and notes payable 254,041 Interest payable 8,154 Income tax payable 1,607 Accrued compensation 44,186 Accrued liabilities 151,608 Deferred income taxes (4) 959,882 Tax reserve non-current 3,130 Pension and other post-retirement obligations 311,106 Other liabilities 101,325 Long-term debt 1,187,290 Total liabilities assumed 3,022,329 Total identifiable net assets acquired 1,774,945 Noncontrolling interest (68,000 ) Goodwill 934,715 Total fair value allocated to net assets acquired $ 2,641,660 ______________________________ (1) The fair value of accounts receivable acquired is $422,274 , with the gross contractual amount being $434,834 . The Company expects $12,560 to be uncollectible. (2) The Company obtained additional information related to its inventories and property, plant and equipment which led to an increase in inventories of $43,047 , a decrease in property, plant and equipment of $188,299 and a corresponding increase in goodwill of $145,252 . (3) The Company obtained additional information related to its customer relationships balances which led to an increase in customer relationships of $80,000 and a corresponding decrease in goodwill. (4) Decreases in the estimated fair values of identified assets acquired led to a decrease in deferred income taxes of $25,246 .

Financial Instruments (Tables)

Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Schedule of Realized Gain (Loss)	Three Months Ended June 30, Six Months Ended June 30, 2016 2016 Proceeds from sales and maturities of securities $ 275,573 $ 302,432 Gross realized gains 1,280 1,341 Gross realized losses (13 ) (22 )

Accounts Receivable (Tables)

Accounts Receivable (Tables)	6 Months Ended
	Jun. 30, 2017
Accounts Receivable, Net [Abstract]
Schedule Of Accounts Receivable	Accounts receivable consist of the following: June 30, December 31, Trade customers $ 1,031,060 $ 819,739 Affiliates 9,105 7,982 Allowance for doubtful accounts (19,602 ) (17,991 ) 1,020,563 809,730 Federal and state taxes 51,462 90,414 Other 23,783 38,599 Accounts receivable, net $ 1,095,808 $ 938,743

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Jun. 30, 2017
Inventory Disclosure [Abstract]
Schedule Of Inventory	Inventories consist of the following: June 30, December 31, Finished products $ 473,011 $ 500,861 Feedstock, additives and chemicals 226,562 216,877 Materials and supplies 132,127 83,362 Inventories $ 831,700 $ 801,100

Other Assets (Tables)

Other Assets (Tables)	6 Months Ended
	Jun. 30, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Changes in Carrying Amount of Goodwill	The gross carrying amounts of goodwill and the changes in the carrying amount of goodwill for the six months ended June 30, 2017 were as follows: Olefins Segment Vinyls Segment Total Balance at December 31, 2016 $ 29,990 $ 916,563 $ 946,553 Goodwill acquired during the period — — — Measurement period adjustment — 47,224 47,224 Effects of changes in foreign exchange rates — 5,837 5,837 Balance at June 30, 2017 $ 29,990 $ 969,624 $ 999,614

Accounts and Notes Payable (Tab

Accounts and Notes Payable (Tables)	6 Months Ended
	Jun. 30, 2017
Payables and Accruals [Abstract]
Schedule of Accounts Payable and Accrued Liabilities	Accounts payable consist of the following: June 30, December 31, Accounts payable—third parties $ 561,190 $ 474,017 Accounts payable to affiliates 21,615 20,726 Notes payable to banks 704 1,516 Accounts payable $ 583,509 $ 496,259

Long-Term Debt (Tables)

Long-Term Debt (Tables)	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Schedule Of Long-Term Debt	Long-term debt consists of the following: June 30, 2017 December 31, 2016 Principal Unamortized Discount Net Principal Unamortized Net Revolving credit facility $ 140,000 $ — $ 140,000 $ 325,000 $ — $ 325,000 4.625% senior notes due 2021 (the "4.625% Westlake 2021 Senior Notes") 624,793 23,502 648,295 624,793 26,837 651,630 4.625% senior notes due 2021 (the "4.625% Subsidiary 2021 Senior Notes") 63,207 2,518 65,725 63,207 2,862 66,069 3.60% senior notes due 2022 250,000 (1,720 ) 248,280 250,000 (1,891 ) 248,109 4.875% senior notes due 2023 (the "4.875% Westlake 2023 Senior Notes") 433,793 12,316 446,109 433,793 13,431 447,224 4.875% senior notes due 2023 (the "4.875% Subsidiary 2023 Senior Notes") 16,207 498 16,705 16,207 540 16,747 3.60% senior notes due 2026 (the "3.60% 2026 Senior Notes") 750,000 (10,312 ) 739,688 750,000 (10,757 ) 739,243 Loan related to tax-exempt waste disposal revenue bonds due 2027 10,889 — 10,889 10,889 — 10,889 6 ½% tax-exempt senior notes due 2029 100,000 (880 ) 99,120 100,000 (916 ) 99,084 6 ¾% tax-exempt senior notes due 2032 250,000 (1,824 ) 248,176 250,000 (1,883 ) 248,117 6 ½% tax-exempt senior notes due 2035 (the "6 ½% 2035 GO Zone Senior Notes") 89,000 (817 ) 88,183 89,000 (839 ) 88,161 6 ½% tax-exempt senior notes due 2035 (the "6 ½% 2035 IKE Zone Senior Notes") 65,000 (586 ) 64,414 65,000 (602 ) 64,398 5.0% senior notes due 2046 (the "5.0% 2046 Senior Notes") 700,000 (25,684 ) 674,316 700,000 (26,017 ) 673,983 Long-term debt, net $ 3,492,889 $ (2,989 ) $ 3,489,900 $ 3,677,889 $ 765 $ 3,678,654

Pension and Post-Retirement B38

Pension and Post-Retirement Benefits (Tables)	6 Months Ended
	Jun. 30, 2017
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Components of Net Periodic Benefit Cost	Components of net periodic benefit cost for the Company's other post-retirement benefits are as follows: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 U.S. Non-U.S. U.S. Non-U.S. U.S. Non-U.S. U.S. Non-U.S. Service cost $ 163 $ 13 $ 5 $ — $ 326 $ 27 $ 10 $ — Interest cost 499 32 145 — 999 65 290 — Amortization of net loss 15 — 32 — 30 — 63 — Net periodic benefit cost $ 677 $ 45 $ 182 $ — $ 1,355 $ 92 $ 363 $ — Components of net periodic benefit cost (income) for the Company's pension plans are as follows: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 U.S. Non-U.S. U.S. Non-U.S. U.S. Non-U.S. U.S. Non-U.S. Service cost $ 1,335 $ 496 $ — $ 137 $ 2,671 $ 981 $ — $ 462 Interest cost 6,198 576 493 582 12,396 1,139 1,060 1,149 Expected return on plan assets (9,976 ) (151 ) (658 ) — (19,952 ) (304 ) (1,460 ) — Amortization of net loss 298 153 337 — 595 304 640 — Net periodic benefit cost (income) $ (2,145 ) $ 1,074 $ 172 $ 719 $ (4,290 ) $ 2,120 $ 240 $ 1,611

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
Schedule of Stockholders Equity	Changes in stockholders' equity for the six months ended June 30, 2017 and 2016 were as follows: Common Stock Common Stock, Held in Treasury Additional Paid-in Capital Retained Earnings Accumulated Other Comprehensive Income (Loss) Noncontrolling Interests Total Balances at December 31, 2016 $ 1,347 $ (319,339 ) $ 550,641 $ 3,412,286 $ (121,306 ) $ 368,416 $ 3,892,045 Net income — — — 291,017 — 13,111 304,128 Other comprehensive income (loss), net of income taxes: Pension and other post- retirement benefits liability — — — — 721 (44 ) 677 Foreign currency translation adjustments — — — — 66,925 2,756 69,681 Other — — — — (164 ) — (164 ) Shares issued—stock- based compensation — 3,187 (1,710 ) — — — 1,477 Stock-based compensation, net of tax on stock options exercised — — 6,547 — — — 6,547 Dividends declared — — — (49,315 ) — — (49,315 ) Distributions to noncontrolling interests — — — — — (16,033 ) (16,033 ) Balances at June 30, 2017 $ 1,347 $ (316,152 ) $ 555,478 $ 3,653,988 $ (53,824 ) $ 368,206 $ 4,209,043 Common Stock Common Stock, Held in Treasury Additional Paid-in Capital Retained Earnings Accumulated Other Comprehensive Income (Loss) Noncontrolling Interests Total Balances at December 31, 2015 $ 1,347 $ (258,312 ) $ 542,148 $ 3,109,987 $ (129,292 ) $ 296,053 $ 3,561,931 Net income — — — 234,252 — 10,304 244,556 Other comprehensive income (loss), net of income taxes Pension and other post- retirement benefits liability — — — — 306 — 306 Foreign currency translation adjustments — — — — 9,305 — 9,305 Net unrealized holding gains on investments — — — — 37,580 — 37,580 Common stock repurchased — (66,725 ) — — — — (66,725 ) Shares issued—stock- based compensation — 2,235 (1,754 ) — — — 481 Stock-based compensation, net of tax on stock options exercised — — 5,403 — — — 5,403 Dividends declared — — — (47,317 ) — — (47,317 ) Distributions to noncontrolling interests — — — — — (8,084 ) (8,084 ) Balances at June 30, 2016 $ 1,347 $ (322,802 ) $ 545,797 $ 3,296,922 $ (82,101 ) $ 298,273 $ 3,737,436
Schedule of Accumulated Other Comprehensive Income (Loss)	Changes in accumulated other comprehensive income (loss) by component for the six months ended June 30, 2017 and 2016 were as follows: Benefits Liability, Net of Tax Cumulative Foreign Currency Exchange, Net of Tax Net Unrealized Holding Gains (Losses) on Investments, Net of Tax Total Balances at December 31, 2016 $ 28,945 $ (150,202 ) $ (49 ) $ (121,306 ) Other comprehensive income (loss) before reclassifications 95 66,925 (164 ) 66,856 Amounts reclassified from accumulated other comprehensive loss 626 — — 626 Net other comprehensive income (loss) for the period 721 66,925 (164 ) 67,482 Balances at June 30, 2017 $ 29,666 $ (83,277 ) $ (213 ) $ (53,824 ) Benefits Liability, Net of Tax Cumulative Foreign Currency Exchange, Net of Tax Net Unrealized Holding Gains (Losses) on Investments, Net of Tax Total Balances at December 31, 2015 $ (8,607 ) $ (115,690 ) $ (4,995 ) $ (129,292 ) Other comprehensive income before reclassifications (127 ) 9,305 38,425 47,603 Amounts reclassified from accumulated other comprehensive loss (income) 433 — (845 ) (412 ) Net other comprehensive income for the period 306 9,305 37,580 47,191 Balances at June 30, 2016 $ (8,301 ) $ (106,385 ) $ 32,585 $ (82,101 )
Reclassification out of Accumulated Other Comprehensive Income (Loss)	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 six months ended June 30, 2017 and 2016 : Details about Accumulated Other Comprehensive Income (Loss) Components Location of Reclassification (Income (Expense)) in Consolidated Statements of Operations Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Amortization of pension and other post-retirement items Net loss (1) $ (466 ) $ (369 ) $ (929 ) $ (703 ) Benefit from income taxes 140 142 303 270 (326 ) (227 ) (626 ) (433 ) Net unrealized gains on available-for-sale investments Realized gain on available-for-sale investments Other income, net — 1,267 — 1,319 Provision for income taxes — (455 ) — (474 ) — 812 — 845 Total reclassifications for the period $ (326 ) $ 585 $ (626 ) $ 412 _____________ (1) These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. For additional information, please read Note 13 (Employee Benefits) to the financial statements included in the 2016 Form 10-K.

Derivative Instruments (Tables)

Derivative Instruments (Tables)	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
ImpactofDerivativesNetInConsolidatedBalanceSheet [Table Text Block]	June 30, 2017 Net Presentation Gross Presentation Net Assets (Liabilities) Presented in the Consolidated Balance Sheets Risk management assets—Commodity forward contracts Risk management liabilities—Commodity forward contracts Accounts receivable, net Derivative positions subject to enforceable master netting arrangements $ — $ — $ — Derivative positions not subject to enforceable master netting arrangements 2,245 2,245 — 2,245 2,245 — Deferred charges and other assets, net Derivative positions subject to enforceable master netting — — — Derivative positions not subject to enforceable master netting 2,273 2,273 — 2,273 2,273 — Accrued liabilities Derivative positions subject to enforceable master netting (203 ) 1,062 (1,265 ) Derivative positions not subject to enforceable master netting (940 ) — (940 ) (1,143 ) 1,062 (2,205 ) Other liabilities Derivative positions subject to enforceable master netting (1,545 ) 771 (2,316 ) Derivative positions not subject to enforceable master netting (3,109 ) — (3,109 ) (4,654 ) 771 (5,425 ) Risk management assets (liabilities)—Commodity forward contracts $ 6,351 $ (7,630 ) December 31, 2016 Net Presentation Gross Presentation Net Assets (Liabilities) Presented in the Consolidated Balance Sheets Risk management assets—Commodity forward contracts Risk management liabilities—Commodity forward contracts Accounts receivable, net Derivative positions subject to enforceable master netting $ 1,498 $ 1,636 $ (138 ) Derivative positions not subject to enforceable master netting 6,091 6,091 — 7,589 7,727 (138 ) Deferred charges and other assets, net Derivative positions subject to enforceable master netting — — — Derivative positions not subject to enforceable master netting 5,249 5,249 — 5,249 5,249 — Accrued liabilities Derivative positions subject to enforceable master netting — — — Derivative positions not subject to enforceable master netting (1,349 ) — (1,349 ) (1,349 ) — (1,349 ) Other liabilities Derivative positions subject to enforceable master netting (436 ) 2,010 (2,446 ) Derivative positions not subject to enforceable master netting (3,288 ) — (3,288 ) (3,724 ) 2,010 (5,734 ) Risk management assets (liabilities)—Commodity forward contracts $ 14,986 $ (7,221 )
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 Hedging Instruments Location of Gain (Loss) Recognized in Income on Derivative Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Commodity forward contracts Cost of sales $ (435 ) $ 11,567 $ (9,602 ) $ 15,624

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2017
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: June 30, 2017 Level 1 Level 2 Total Derivative instruments Risk management assets—Commodity forward contracts $ 567 $ 5,784 $ 6,351 Risk management liabilities—Commodity forward contracts (6,692 ) (938 ) (7,630 ) December 31, 2016 Level 1 Level 2 Total Derivative instruments Risk management assets—Commodity forward contracts $ 878 $ 14,108 $ 14,986 Risk management liabilities—Commodity forward contracts (6,854 ) (367 ) (7,221 )
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 fair value of the Company's long-term debt instruments is determined using a market approach, based upon quotes from financial reporting services. 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. June 30, 2017 December 31, 2016 Carrying Value Fair Value Carrying Value Fair Value Revolving credit facility $ 140,000 $ 140,000 $ 325,000 $ 325,000 4.625% Westlake 2021 Senior Notes 648,295 649,054 651,630 650,847 4.625% Subsidiary 2021 Senior Notes 65,725 65,930 66,069 65,775 3.60% senior notes due 2022 248,280 255,255 248,109 251,725 4.875% Westlake 2023 Senior Notes 446,109 453,092 447,224 451,301 4.875% Subsidiary 2023 Senior Notes 16,705 16,923 16,747 16,501 3.60% 2026 Senior Notes 739,688 744,946 739,243 722,055 Loan related to tax-exempt waste disposal revenue bonds due 2027 10,889 10,889 10,889 10,889 6 ½% tax-exempt senior notes due 2029 99,120 113,358 99,084 112,433 6 ¾% tax-exempt senior notes due 2032 248,176 254,100 248,117 258,818 6 ½% 2035 GO Zone Senior Notes 88,183 101,589 88,161 100,323 6 ½% 2035 IKE Zone Senior Notes 64,414 74,190 64,398 73,270 5.0% 2046 Senior Notes 674,316 741,265 673,983 691,712

Earnings per Share (Tables)

Earnings per Share (Tables)	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Schedule Of Net Income Attributable To Common Stockholders	Diluted earnings per share include the effect of certain stock options. Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Net income attributable to Westlake Chemical Corporation $ 152,827 $ 111,124 $ 291,017 $ 234,252 Less: Net income attributable to participating securities (819 ) (504 ) (1,513 ) (1,054 ) Net income attributable to common shareholders $ 152,008 $ 110,620 $ 289,504 $ 233,198
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 June 30, Six Months Ended June 30, 2017 2016 2017 2016 Weighted average common shares—basic 129,051,227 129,583,224 129,015,507 129,886,594 Plus incremental shares from: Assumed exercise of options 735,487 397,303 724,136 403,927 Weighted average common shares—diluted 129,786,714 129,980,527 129,739,643 130,290,521 Earnings per common share attributable to Westlake Chemical Corporation: Basic $ 1.18 $ 0.85 $ 2.24 $ 1.80 Diluted $ 1.17 $ 0.85 $ 2.23 $ 1.79

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Segment Reporting Information	Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Net external sales Olefins Polyethylene $ 358,392 $ 371,658 $ 744,334 $ 717,690 Styrene, feedstock and other 130,842 122,826 287,895 207,814 Total Olefins 489,234 494,484 1,032,229 925,504 Vinyls PVC, caustic soda and other 1,157,317 462,472 2,288,446 893,374 Building products 332,610 129,105 601,102 242,370 Total Vinyls 1,489,927 591,577 2,889,548 1,135,744 $ 1,979,161 $ 1,086,061 $ 3,921,777 $ 2,061,248 Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Intersegment sales Olefins $ 97,992 $ 27,293 $ 183,936 $ 55,242 Vinyls 319 225 611 589 $ 98,311 $ 27,518 $ 184,547 $ 55,831 Income (loss) from operations Olefins $ 143,277 $ 140,564 $ 323,095 $ 289,799 Vinyls 143,320 52,208 214,761 114,324 Corporate and other (19,481 ) (12,834 ) (35,442 ) (21,909 ) $ 267,116 $ 179,938 $ 502,414 $ 382,214 Depreciation and amortization Olefins $ 35,175 $ 30,236 $ 76,215 $ 58,933 Vinyls 106,822 36,268 214,095 72,555 Corporate and other 2,633 746 4,589 1,476 $ 144,630 $ 67,250 $ 294,899 $ 132,964 Other income (expense), net Olefins $ 588 $ 1,093 $ 1,738 $ 2,606 Vinyls (1,534 ) 4,466 2,058 2,949 Corporate and other 408 2,622 737 5,271 $ (538 ) $ 8,181 $ 4,533 $ 10,826 Provision for (benefit from) income taxes Olefins $ 36,453 $ 51,940 $ 94,264 $ 104,473 Vinyls 39,237 16,297 54,195 33,567 Corporate and other (7,502 ) (1,653 ) (24,388 ) (2,156 ) $ 68,188 $ 66,584 $ 124,071 $ 135,884 Capital expenditures Olefins $ 23,733 $ 93,739 $ 49,083 $ 188,890 Vinyls 114,372 56,613 222,454 96,869 Corporate and other 8,512 481 9,365 1,401 $ 146,617 $ 150,833 $ 280,902 $ 287,160
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 June 30, Six Months Ended June 30, 2017 2016 2017 2016 Income from operations $ 267,116 $ 179,938 $ 502,414 $ 382,214 Interest expense (38,972 ) (5,915 ) (78,748 ) (12,600 ) Other income (expense), net (538 ) 8,181 4,533 10,826 Income before income taxes $ 227,606 $ 182,204 $ 428,199 $ 380,440
Total Assets	June 30, December 31, Total assets Olefins $ 2,077,986 $ 2,092,617 Vinyls 8,379,465 8,287,204 Corporate and other 428,256 510,432 $ 10,885,707 $ 10,890,253

Guarantor Disclosures (Tables)

Guarantor Disclosures (Tables)	6 Months Ended
	Jun. 30, 2017
Guarantees [Abstract]
Condensed Consolidating Financial Information Balance Sheet	Condensed Consolidating Financial Information as of June 30, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Balance Sheet Current assets Cash and cash equivalents $ 49,366 $ 15,399 $ 331,011 $ — $ 395,776 Accounts receivable, net 2,742,556 3,785,141 364,318 (5,796,207 ) 1,095,808 Inventories — 631,802 199,898 — 831,700 Prepaid expenses and other current assets 75,730 40,213 9,349 (79,548 ) 45,744 Restricted cash — 1,500 7,107 — 8,607 Total current assets 2,867,652 4,474,055 911,683 (5,875,755 ) 2,377,635 Property, plant and equipment, net — 4,326,202 1,990,529 — 6,316,731 Other assets, net Goodwill — 847,816 151,798 — 999,614 Customer relationships, net — 509,933 144,159 — 654,092 Other intangible assets, net — 97,224 72,767 — 169,991 Deferred charges and other assets, net 9,552,799 790,393 1,540,773 (11,516,321 ) 367,644 Total other assets, net 9,552,799 2,245,366 1,909,497 (11,516,321 ) 2,191,341 Total assets $ 12,420,451 $ 11,045,623 $ 4,811,709 $ (17,392,076 ) $ 10,885,707 Current liabilities Accounts payable $ 5,183,033 $ 815,642 $ 343,531 $ (5,758,697 ) $ 583,509 Accrued liabilities — 355,132 209,338 (117,058 ) 447,412 Total current liabilities 5,183,033 1,170,774 552,869 (5,875,755 ) 1,030,921 Long-term debt, net 3,396,581 4,537,551 421,405 (4,865,637 ) 3,489,900 Deferred income taxes — 1,573,733 97,781 (22,985 ) 1,648,529 Pension and other liabilities — 365,170 142,144 — 507,314 Total liabilities 8,579,614 7,647,228 1,214,199 (10,764,377 ) 6,676,664 Total Westlake Chemical Corporation stockholders' equity 3,840,837 3,398,395 3,229,304 (6,627,699 ) 3,840,837 Noncontrolling interests — — 368,206 — 368,206 Total equity 3,840,837 3,398,395 3,597,510 (6,627,699 ) 4,209,043 Total liabilities and equity $ 12,420,451 $ 11,045,623 $ 4,811,709 $ (17,392,076 ) $ 10,885,707 Condensed Consolidating Financial Information as of December 31, 2016 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Balance Sheet Current assets Cash and cash equivalents $ 146,990 $ 53,006 $ 259,457 $ — $ 459,453 Accounts receivable, net 2,117,540 3,329,871 323,931 (4,832,599 ) 938,743 Inventories — 597,819 203,281 — 801,100 Prepaid expenses and other current assets 30,748 41,755 12,494 (36,504 ) 48,493 Restricted cash — — 160,527 — 160,527 Total current assets 2,295,278 4,022,451 959,690 (4,869,103 ) 2,408,316 Property, plant and equipment, net — 4,475,943 1,944,119 — 6,420,062 Other assets, net Goodwill — 791,706 154,847 — 946,553 Customer relationships, net — 468,645 142,970 — 611,615 Other intangible assets, net — 130,243 71,177 (25,581 ) 175,839 Deferred charges and other assets, net 9,170,042 874,003 1,115,877 (10,832,054 ) 327,868 Total other assets, net 9,170,042 2,264,597 1,484,871 (10,857,635 ) 2,061,875 Total assets $ 11,465,320 $ 10,762,991 $ 4,388,680 $ (15,726,738 ) $ 10,890,253 Current liabilities Accounts payable $ 4,330,375 $ 748,364 $ 225,300 $ (4,807,780 ) $ 496,259 Accrued liabilities 26,367 389,216 183,223 (61,323 ) 537,483 Term loan — — 149,341 — 149,341 Total current liabilities 4,356,742 1,137,580 557,864 (4,869,103 ) 1,183,083 Long-term debt, net 3,584,949 4,090,775 — (3,997,070 ) 3,678,654 Deferred income taxes — 1,581,260 91,809 (22,494 ) 1,650,575 Pension and other liabilities — 360,622 125,274 — 485,896 Total liabilities 7,941,691 7,170,237 774,947 (8,888,667 ) 6,998,208 Total Westlake Chemical Corporation stockholders' equity 3,523,629 3,592,754 3,245,317 (6,838,071 ) 3,523,629 Noncontrolling interests — — 368,416 — 368,416 Total equity 3,523,629 3,592,754 3,613,733 (6,838,071 ) 3,892,045 Total liabilities and equity $ 11,465,320 $ 10,762,991 $ 4,388,680 $ (15,726,738 ) $ 10,890,253
Condensed Consolidating Financial Information Statement Of Operations	Condensed Consolidating Financial Information for the Three Months Ended June 30, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Operations Net sales $ — $ 1,596,952 $ 804,002 $ (421,793 ) $ 1,979,161 Cost of sales — 1,346,983 641,349 (415,005 ) 1,573,327 Gross profit — 249,969 162,653 (6,788 ) 405,834 Selling, general and administrative expenses 142 95,845 41,427 (6,788 ) 130,626 Transaction and integration-related costs — 8,092 — — 8,092 Income (loss) from operations (142 ) 146,032 121,226 — 267,116 Other income (expense) Interest expense (38,160 ) (45,783 ) (34 ) 45,005 (38,972 ) Other income (expense), net 37,282 3,550 3,635 (45,005 ) (538 ) Income (loss) before income taxes (1,020 ) 103,799 124,827 — 227,606 Provision for (benefit from) income taxes 4,616 52,083 11,489 — 68,188 Equity in net income of subsidiaries 158,463 — — (158,463 ) — Net income 152,827 51,716 113,338 (158,463 ) 159,418 Net income attributable to noncontrolling interests — — 6,591 — 6,591 Net income attributable to Westlake Chemical Corporation $ 152,827 $ 51,716 $ 106,747 $ (158,463 ) $ 152,827 Comprehensive income attributable to Westlake Chemical Corporation $ 203,090 $ 51,776 $ 148,417 $ (200,193 ) $ 203,090 Condensed Consolidating Financial Information for the Three Months Ended June 30, 2016 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Operations Net sales $ — $ 820,190 $ 553,173 $ (287,302 ) $ 1,086,061 Cost of sales — 698,096 428,898 (282,299 ) 844,695 Gross profit — 122,094 124,275 (5,003 ) 241,366 Selling, general and administrative expenses 950 44,020 21,461 (5,003 ) 61,428 Income (loss) from operations (950 ) 78,074 102,814 — 179,938 Other income (expense) Interest expense (11,151 ) (5,686 ) (205 ) 11,127 (5,915 ) Other income (expense), net 4,050 (1,183 ) 16,441 (11,127 ) 8,181 Income (loss) before income taxes (8,051 ) 71,205 119,050 — 182,204 Provision for (benefit from) income taxes (2,960 ) 55,671 13,873 — 66,584 Equity in net income of subsidiaries 116,215 — — (116,215 ) — Net income 111,124 15,534 105,177 (116,215 ) 115,620 Net income attributable to noncontrolling interests — — 4,496 — 4,496 Net income attributable to Westlake Chemical Corporation $ 111,124 $ 15,534 $ 100,681 $ (116,215 ) $ 111,124 Comprehensive income attributable to Westlake Chemical Corporation $ 119,686 $ 15,634 $ 102,296 $ (117,930 ) $ 119,686 Condensed Consolidating Financial Information for the Six Months Ended June 30, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Operations Net sales $ — $ 3,176,677 $ 1,540,087 $ (794,987 ) $ 3,921,777 Cost of sales — 2,706,258 1,224,009 (781,467 ) 3,148,800 Gross profit — 470,419 316,078 (13,520 ) 772,977 Selling, general and administrative expenses 919 188,109 78,769 (13,520 ) 254,277 Transaction and integration-related costs — 16,224 62 — 16,286 Income (loss) from operations (919 ) 266,086 237,247 — 502,414 Other income (expense) Interest expense (76,345 ) (91,460 ) (840 ) 89,897 (78,748 ) Other income (expense), net 74,439 3,293 16,698 (89,897 ) 4,533 Income (loss) before income taxes (2,825 ) 177,919 253,105 — 428,199 Provision for (benefit from) income taxes (851 ) 105,455 19,467 — 124,071 Equity in net income of subsidiaries 292,991 — — (292,991 ) — Net income 291,017 72,464 233,638 (292,991 ) 304,128 Net income attributable to noncontrolling interests — — 13,111 — 13,111 Net income attributable to Westlake Chemical Corporation $ 291,017 $ 72,464 $ 220,527 $ (292,991 ) $ 291,017 Comprehensive income attributable to Westlake Chemical Corporation $ 355,787 $ 72,449 $ 259,034 $ (331,483 ) $ 355,787 Condensed Consolidating Financial Information for the Six Months Ended June 30, 2016 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Operations Net sales $ — $ 1,581,931 $ 1,122,992 $ (643,675 ) $ 2,061,248 Cost of sales — 1,340,833 856,668 (633,204 ) 1,564,297 Gross profit — 241,098 266,324 (10,471 ) 496,951 Selling, general and administrative expenses 1,557 81,017 42,634 (10,471 ) 114,737 Income (loss) from operations (1,557 ) 160,081 223,690 — 382,214 Other income (expense) Interest expense (21,563 ) (12,471 ) (459 ) 21,893 (12,600 ) Other income (expense), net 5,865 (75 ) 26,929 (21,893 ) 10,826 Income (loss) before income taxes (17,255 ) 147,535 250,160 — 380,440 Provision for (benefit from) income taxes (6,182 ) 117,874 24,192 — 135,884 Equity in net income of subsidiaries 245,325 — — (245,325 ) — Net income 234,252 29,661 225,968 (245,325 ) 244,556 Net income attributable to noncontrolling interests — — 10,304 — 10,304 Net income attributable to Westlake Chemical Corporation $ 234,252 $ 29,661 $ 215,664 $ (245,325 ) $ 234,252 Comprehensive income attributable to Westlake Chemical Corporation $ 281,443 $ 29,967 $ 254,514 $ (284,481 ) $ 281,443
Condensed Consolidating Financial Information Statement Of Cash Flows	Condensed Consolidating Financial Information for the Six Months Ended June 30, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Cash Flows Cash flows from operating activities Net income $ 291,017 $ 72,464 $ 233,638 $ (292,991 ) $ 304,128 Adjustments to reconcile net income to net cash provided by (used for) operating activities Depreciation and amortization — 193,594 101,305 — 294,899 Deferred income taxes (126 ) 15,207 (119 ) — 14,962 Net changes in working capital and other (400,511 ) (25,601 ) (1,154 ) 292,991 (134,275 ) Net cash provided by (used for) operating activities (109,620 ) 255,664 333,670 — 479,714 Cash flows from investing activities Additions to property, plant and equipment — (198,621 ) (82,281 ) — (280,902 ) Additions to cost method investment — (31,000 ) — — (31,000 ) Proceeds from disposition of assets — 3 130 — 133 Proceeds from involuntary conversion of assets — 1,672 — — 1,672 Settlements of derivative instruments — (376 ) — — (376 ) Net cash used for investing activities — (228,322 ) (82,151 ) — (310,473 ) Cash flows from financing activities Intercompany financing 241,210 (253,075 ) 11,865 — — Dividends paid (49,315 ) — — — (49,315 ) Distributions to noncontrolling interests — 188,646 (204,679 ) — (16,033 ) Proceeds from issuance of notes payable — — 3,544 — 3,544 Proceeds from drawdown of revolver 175,000 — — — 175,000 Restricted cash associated with term loan 154,000 — — — 154,000 Repayment of term loan (150,000 ) — — — (150,000 ) Repayment of notes payable — (520 ) (4,381 ) — (4,901 ) Repayment of revolver (360,000 ) — — — (360,000 ) Other, net 1,101 — — — 1,101 Net cash provided by (used for) financing activities 11,996 (64,949 ) (193,651 ) — (246,604 ) Effect of exchange rate changes on cash and cash equivalents — — 13,686 — 13,686 Net increase (decrease) in cash and cash equivalents (97,624 ) (37,607 ) 71,554 — (63,677 ) Cash and cash equivalents at beginning of period 146,990 53,006 259,457 — 459,453 Cash and cash equivalents at end of period $ 49,366 $ 15,399 $ 331,011 $ — $ 395,776 Condensed Consolidating Financial Information for the Six Months Ended June 30, 2016 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Cash Flows Cash flows from operating activities Net income $ 234,252 $ 29,661 $ 225,968 $ (245,325 ) $ 244,556 Adjustments to reconcile net income to net cash provided by operating activities Depreciation and amortization — 66,137 66,827 — 132,964 Deferred income taxes (4,802 ) 96,990 10,802 — 102,990 Net changes in working capital and other (274,585 ) (38,234 ) (43,124 ) 245,325 (110,618 ) Net cash provided by (used for) operating activities (45,135 ) 154,554 260,473 — 369,892 Cash flows from investing activities Additions to property, plant and equipment — (94,775 ) (192,385 ) — (287,160 ) Proceeds from disposition of assets — 7 98 — 105 Proceeds from sales and maturities of securities 302,432 — — — 302,432 Purchase of securities (130,830 ) (7,592 ) — — (138,422 ) Settlements of derivative instruments — (3,372 ) — — (3,372 ) Net cash provided by (used for) investing activities 171,602 (105,732 ) (192,287 ) — (126,417 ) Cash flows from financing activities Intercompany financing 106,904 (212,948 ) 106,044 — — Debt issuance costs (9,700 ) — — — (9,700 ) Dividends paid (47,317 ) — — — (47,317 ) Distributions to noncontrolling interests — 158,392 (166,476 ) — (8,084 ) Proceeds from issuance of notes payable — — 3,842 — 3,842 Repayment of notes payable — — (8,626 ) — (8,626 ) Repurchase of common stock for treasury (67,404 ) — — — (67,404 ) Other 800 — — — 800 Net cash used for financing activities (16,717 ) (54,556 ) (65,216 ) — (136,489 ) Effect of exchange rate changes on cash and cash equivalents — — 1,486 1,486 Net increase (decrease) in cash and cash equivalents 109,750 (5,734 ) 4,456 — 108,472 Cash and cash equivalents at beginning of period 303,131 6,818 352,576 — 662,525 Cash and cash equivalents at end of period $ 412,881 $ 1,084 $ 357,032 $ — $ 770,997

Acquisition (Narrative) (Detail

Acquisition (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	Aug. 31, 2016	Aug. 30, 2016	Jun. 30, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill			$ 999,614	$ 946,553
Axiall Corporation [Member]
Business Acquisition [Line Items]
Equity interest in acquiree held prior to combination, shares		3.1
Offer per share	$ 33
Purchase consideration	$ 2,539,360
Goodwill	$ 934,715

Acquisition (Allocation of Purc

Acquisition (Allocation of Purchase Consideration) (Details) - Axiall Corporation [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Aug. 31, 2016	Aug. 30, 2016
Business Acquisition [Line Items]
Offer per share	$ 33
Multiplied by number of shares outstanding at acquisition	67,277
Fair value of Axiall shares outstanding purchased by the Company	$ 2,220,141
Axiall debt repaid at acquisition	247,135
Seller's transaction costs paid by the Company	47,458
Total fair value of consideration transferred	2,514,734
Fair value of Axiall share-based awards attributed to pre-combination service	11,346
Additional settlement value of shares acquired	13,280
Purchase consideration	2,539,360
Fair value of previously held equity interest in Axiall	102,300
Total fair value allocated to net assets acquired	2,641,660
Equity interest in acquiree held prior to combination, shares		3,100
Step acquisition, equity interest in acquiree, remeasurement gain (loss), net	$ 49,080

Acquisition (Purchase Price All

Acquisition (Purchase Price Allocation) (Details) - USD ($) $ in Thousands	Aug. 31, 2016	Jun. 30, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill		$ 999,614	$ 946,553
Goodwill, Purchase Accounting Adjustments		$ 47,224
Customer Relationships [Member]
Business Acquisition [Line Items]
Weighted average useful life	9 years 9 months 18 days
Trade Name [Member]
Business Acquisition [Line Items]
Weighted average useful life	6 years 9 months 18 days
Technology [Member]
Business Acquisition [Line Items]
Weighted average useful life	5 years 4 months 24 days
Supply Contracts and Leases [Member]
Business Acquisition [Line Items]
Weighted average useful life	6 years 3 months 18 days
Axiall Corporation [Member]
Business Acquisition [Line Items]
Cash	$ 88,251
Accounts receivable (1)	422,274
Income tax receivable	50,980
Inventories (2)	349,205
Prepaid expenses and other current assets	55,462
Property, plant and equipment (2)	2,946,442
Other assets	95,872
Total assets acquired	4,797,274
Accounts and notes payable	254,041
Interest payable	8,154
Income tax payable	1,607
Accrued compensation	44,186
Accrued liabilities	151,608
Deferred income taxes (4)	959,882
Tax reserve non-current	3,130
Pension and other post-retirement obligations	311,106
Other liabilities	101,325
Long-term debt	1,187,290
Total liabilities assumed	3,022,329
Total identifiable net assets acquired	1,774,945
Noncontrolling interest	(68,000)
Goodwill	934,715
Total fair value allocated to net assets acquired	2,641,660
Business Combination, Acquired Receivables, Fair Value	422,274
Business Combination, Acquired Receivables, Gross Contractual Amount	434,834
Business Combination, Acquired Receivables, Estimated Uncollectible	12,560
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Inventory	43,047
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment	188,299
Goodwill, Purchase Accounting Adjustments	145,252
Axiall Corporation [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	670,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles	80,000
Axiall Corporation [Member] | Trade Name [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	50,000
Axiall Corporation [Member] | Technology [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	41,500
Axiall Corporation [Member] | Supply Contracts and Leases [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	27,288
Deferred Income Tax Charge [Member]
Business Acquisition [Line Items]
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments Related to Previous Period	$ 25,246

Financial Instruments (Cash Equ

Financial Instruments (Cash Equivalents) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 9,996	$ 0

Financial Instruments (Restrict

Financial Instruments (Restricted Cash Equivalents) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Restricted cash	$ 31,538	$ 186,216
Current	8,607	160,527
Noncurrent	$ 22,931	$ 25,689

Financial Instruments (Availabl

Financial Instruments (Available-for-Sale Marketable Securities) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Available-for-sale Securities	$ 0		$ 0		$ 0
Gain (Loss) on Investments [Line Items]
Proceeds from Sale and Maturity of Available-for-sale Securities	$ 0	$ 275,573	$ 0	$ 302,432
Available-for-sale Securities, Gross Realized Gains		1,280		1,341
Available-for-sale Securities, Gross Realized Losses		$ (13)		$ (22)

Accounts Receivable (Details)

Accounts Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accounts Receivable, Net [Abstract]
Trade customers	$ 1,031,060	$ 819,739
Affiliates	9,105	7,982
Allowance for doubtful accounts	(19,602)	(17,991)
Accounts receivable from trade customers, net	1,020,563	809,730
Federal and state taxes	51,462	90,414
Other	23,783	38,599
Accounts receivable, net	$ 1,095,808	$ 938,743

Inventories (Inventories) (Deta

Inventories (Inventories) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Finished products	$ 473,011	$ 500,861
Feedstock, additives and chemicals	226,562	216,877
Materials and supplies	132,127	83,362
Inventories	$ 831,700	$ 801,100

Property, Plant and Equipment (

Property, Plant and Equipment (Property, Plant and Equipment) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Property, plant and equipment, net	$ 6,316,731		$ 6,316,731		$ 6,420,062
Depreciation expense on property, plant and equipment	$ 104,294	$ 57,930	$ 218,385	$ 113,971

Other Assets (Amortization Expe

Other Assets (Amortization Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other Assets [Member]
Other Assets [Line Items]
Amortization of Intangible Assets	$ 40,488	$ 9,269	$ 76,818	$ 19,163

Other Assets (Changes in Goodwi

Other Assets (Changes in Goodwill) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017USD ($)
Goodwill [Roll Forward]
Beginning Balance	$ 946,553
Goodwill acquired during the period	0
Goodwill, Purchase Accounting Adjustments	47,224
Effects of changes in foreign exchange rates	5,837
Ending Balance	999,614
Olefins [Member]
Goodwill [Roll Forward]
Beginning Balance	29,990
Goodwill acquired during the period	0
Goodwill, Purchase Accounting Adjustments	0
Effects of changes in foreign exchange rates	0
Ending Balance	29,990
Vinyls [Member]
Goodwill [Roll Forward]
Beginning Balance	916,563
Goodwill acquired during the period	0
Goodwill, Purchase Accounting Adjustments	47,224
Effects of changes in foreign exchange rates	5,837
Ending Balance	$ 969,624

Accounts and Notes Payable (Acc

Accounts and Notes Payable (Accounts Payable) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accounts payable—third parties	$ 561,190	$ 474,017
Accounts payable to affiliates	21,615	20,726
Notes payable to banks	704	1,516
Accounts payable	$ 583,509	$ 496,259

Term Loan (Narrative) (Details)

Term Loan (Narrative) (Details) - Line of Credit [Member] - Term Loan Facility Maturing March 31, 2017 [Member]	Aug. 10, 2016USD ($)
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 150,000,000
LIBOR [Member]
Line of Credit Facility [Line Items]
Percentage added to basis to find interest rate	2.00%

Long-Term Debt (Schedule of Lon

Long-Term Debt (Schedule of Long-term Debt) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Debt Instrument [Line Items]
Principal Amount	$ 3,492,889	$ 3,677,889
Unamortized Premium, Discount and Debt Issuance Costs,	(2,989)	765
Net, Long-term Debt	3,489,900	3,678,654
Line of Credit [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Principal Amount	140,000	325,000
Unamortized Premium, Discount and Debt Issuance Costs,	0	0
Net, Long-term Debt	$ 140,000	325,000
Senior Notes [Member] | 4.625% Senior Notes Due 2021 (New Westlake 2021 Notes) [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,021
Stated interest rate (percent)	4.625%		4.625%
Principal Amount	$ 624,793	624,793
Unamortized Premium, Discount and Debt Issuance Costs,	23,502	26,837
Net, Long-term Debt	$ 648,295	651,630
Senior Notes [Member] | 4.625% Senior Notes Due 2021 (Existing Axiall 2021 Notes) [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,021
Stated interest rate (percent)	4.625%		4.625%
Principal Amount	$ 63,207	63,207	$ 688,000
Unamortized Premium, Discount and Debt Issuance Costs,	2,518	2,862
Net, Long-term Debt	$ 65,725	66,069
Senior Notes [Member] | 3.60% Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,022
Stated interest rate (percent)	3.60%
Principal Amount	$ 250,000	250,000
Unamortized Premium, Discount and Debt Issuance Costs,	(1,720)	(1,891)
Net, Long-term Debt	$ 248,280	248,109
Senior Notes [Member] | 4.875% Senior Notes Due 2023 (New Westlake 2023 Notes) [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,023
Stated interest rate (percent)	4.875%		4.875%
Principal Amount	$ 433,793	433,793
Unamortized Premium, Discount and Debt Issuance Costs,	12,316	13,431
Net, Long-term Debt	$ 446,109	447,224
Senior Notes [Member] | 4.875% Senior Notes Due 2023 (Existing Axiall 2023 Notes) [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,023
Stated interest rate (percent)	4.875%		4.875%
Principal Amount	$ 16,207	16,207	$ 450,000
Unamortized Premium, Discount and Debt Issuance Costs,	498	540
Net, Long-term Debt	$ 16,705	16,747
Senior Notes [Member] | 3.6% Senior Notes Due 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,026
Stated interest rate (percent)	3.60%
Principal Amount	$ 750,000	750,000
Unamortized Premium, Discount and Debt Issuance Costs,	(10,312)	(10,757)
Net, Long-term Debt	$ 739,688	739,243
Senior Notes [Member] | Loan related to tax-exempt waste disposal revenue bonds due 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,027
Principal Amount	$ 10,889	10,889
Unamortized Premium, Discount and Debt Issuance Costs,	0	0
Net, Long-term Debt	$ 10,889	10,889
Senior Notes [Member] | 6 1/2% Senior Notes Due 2029 [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,029
Stated interest rate (percent)	6.50%
Principal Amount	$ 100,000	100,000
Unamortized Premium, Discount and Debt Issuance Costs,	(880)	(916)
Net, Long-term Debt	$ 99,120	99,084
Senior Notes [Member] | 6 3/4% Senior Notes Due 2032 [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,032
Stated interest rate (percent)	6.75%
Principal Amount	$ 250,000	250,000
Unamortized Premium, Discount and Debt Issuance Costs,	(1,824)	(1,883)
Net, Long-term Debt	$ 248,176	248,117
Senior Notes [Member] | 2035 GO Zone 6 1/2% Notes [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,035
Stated interest rate (percent)	6.50%
Principal Amount	$ 89,000	89,000
Unamortized Premium, Discount and Debt Issuance Costs,	(817)	(839)
Net, Long-term Debt	$ 88,183	88,161
Senior Notes [Member] | 2035 IKE Zone 6 1/2% Notes [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,035
Stated interest rate (percent)	6.50%
Principal Amount	$ 65,000	65,000
Unamortized Premium, Discount and Debt Issuance Costs,	(586)	(602)
Net, Long-term Debt	$ 64,414	64,398
Senior Notes [Member] | 5% Senior Notes Due 2046 [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,046
Stated interest rate (percent)	5.00%
Principal Amount	$ 700,000	700,000
Unamortized Premium, Discount and Debt Issuance Costs,	(25,684)	(26,017)
Net, Long-term Debt	$ 674,316	$ 673,983

Long-Term Debt (Revolving Credi

Long-Term Debt (Revolving Credit Facility) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Line of Credit Facility [Line Items]
Principal amount	$ 3,492,889	$ 3,677,889
Line of Credit [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Principal amount	$ 140,000	$ 325,000
Line of Credit Facility, Interest Rate at Period End	2.51%
Letters of credit outstanding	$ 76,525
Remaining borrowing capacity	$ 783,475

Long-Term Debt (Senior Notes) (

Long-Term Debt (Senior Notes) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Aug. 10, 2016
Debt Instrument [Line Items]
Principal amount	$ 3,492,889	$ 3,677,889
Unamortized Debt Issuance Expense	$ 23,281	$ 24,113
Senior Notes [Member] | 3.60% Percentage Senior Notes Due 2026 [Member]
Debt Instrument [Line Items]
Principal amount			$ 750,000
Stated interest rate (percent)			3.60%
Senior Notes [Member] | 5.0% Percentage Senior Notes Due 2046 [Member]
Debt Instrument [Line Items]
Principal amount			$ 700,000
Stated interest rate (percent)			5.00%

Long-Term Debt (Exchange Offers

Long-Term Debt (Exchange Offers) (Details) - USD ($) $ in Thousands	Mar. 27, 2017	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Aug. 10, 2016
Debt Instrument [Line Items]
Principal amount		$ 3,492,889	$ 3,677,889
Senior Notes [Member] | 3.60% Percentage Senior Notes Due 2026 [Member]
Debt Instrument [Line Items]
Principal amount					$ 750,000
Stated interest rate (percent)					3.60%
Exchange Offer Percentage	99.9667%
Senior Notes [Member] | 5.0% Percentage Senior Notes Due 2046 [Member]
Debt Instrument [Line Items]
Principal amount					$ 700,000
Stated interest rate (percent)					5.00%
Exchange Offer Percentage	100.00%
Senior Notes [Member] | 4.625% Senior Notes Due 2021 (New Westlake 2021 Notes) [Member]
Debt Instrument [Line Items]
Principal amount		$ 624,793	624,793
Stated interest rate (percent)		4.625%		4.625%
Senior Notes [Member] | 4.875% Senior Notes Due 2023 (New Westlake 2023 Notes) [Member]
Debt Instrument [Line Items]
Principal amount		$ 433,793	433,793
Stated interest rate (percent)		4.875%		4.875%
Senior Notes [Member] | 4.625% Senior Notes Due 2021 (Existing Axiall 2021 Notes) [Member]
Debt Instrument [Line Items]
Principal amount		$ 63,207	63,207	$ 688,000
Stated interest rate (percent)		4.625%		4.625%
Exchange Offer Percentage	100.00%
Senior Notes [Member] | 4.875% Senior Notes Due 2023 (Existing Axiall 2023 Notes) [Member]
Debt Instrument [Line Items]
Principal amount		$ 16,207	$ 16,207	$ 450,000
Stated interest rate (percent)		4.875%		4.875%

Pension and Post-Retirement B62

Pension and Post-Retirement Benefits (Components of Net Periodic Benefit Cost) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
United States Pension Plan of US Entity [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer			$ 5,139,000	$ 0
Service cost	$ 1,335,000	$ 0	2,671,000	0
Interest cost	6,198,000	493,000	12,396,000	1,060,000
Expected return on plan assets	(9,976,000)	(658,000)	(19,952,000)	(1,460,000)
Amortization of net loss	298,000	337,000	595,000	640,000
Net periodic benefit cost (income)	(2,145,000)	172,000	(4,290,000)	240,000
Non-US Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer			514,000	0
Service cost	496,000	137,000	981,000	462,000
Interest cost	576,000	582,000	1,139,000	1,149,000
Expected return on plan assets	(151,000)	0	(304,000)	0
Amortization of net loss	153,000	0	304,000	0
Net periodic benefit cost (income)	1,074,000	719,000	2,120,000	1,611,000
United States Postretirement Benefit Plan of US Entity [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	163,000	5,000	326,000	10,000
Interest cost	499,000	145,000	999,000	290,000
Amortization of net loss	15,000	32,000	30,000	63,000
Net periodic benefit cost (income)	677,000	182,000	1,355,000	363,000
Non-U.S. Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	13,000	0	27,000	0
Interest cost	32,000	0	65,000	0
Amortization of net loss	0	0	0	0
Net periodic benefit cost (income)	$ 45,000	$ 0	$ 92,000	$ 0

Pension and Post-Retirement B63

Pension and Post-Retirement Benefits (Additional Information) (Details) - USD ($)	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
United States Pension Plan of US Entity [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer	$ 5,139,000	$ 0
Estimated future employer contributions in current fiscal year	5,139,000
Non-US Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer	514,000	$ 0
Estimated future employer contributions in current fiscal year	$ 273,000

Stockholders' Equity (Changes i

Stockholders' Equity (Changes in Stockholders Equity) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 3,892,045	$ 3,561,931
Net income	$ 159,418	$ 115,620	304,128	244,556
Pension and other post- retirement benefits liability			677	306
Foreign currency translation adjustments			69,681	9,305
Other			(164)	37,580
Common stock repurchased				(66,725)
Shares issued—stock- based compensation			1,477	481
Stock-based compensation, net of tax on stock options exercised			6,547	5,403
Dividends declared			(49,315)	(47,317)
Distributions to noncontrolling interests			(16,033)	(8,084)
Ending balance	4,209,043	3,737,436	4,209,043	3,737,436
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			1,347	1,347
Shares issued—stock- based compensation			0	0
Ending balance	1,347	1,347	1,347	1,347
Treasury Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			(319,339)	(258,312)
Common stock repurchased				(66,725)
Shares issued—stock- based compensation			3,187	2,235
Ending balance	(316,152)	(322,802)	(316,152)	(322,802)
Additional Paid-in Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			550,641	542,148
Shares issued—stock- based compensation			(1,710)	(1,754)
Stock-based compensation, net of tax on stock options exercised			6,547	5,403
Ending balance	555,478	545,797	555,478	545,797
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			3,412,286	3,109,987
Net income			291,017	234,252
Dividends declared			(49,315)	(47,317)
Ending balance	3,653,988	3,296,922	3,653,988	3,296,922
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			(121,306)	(129,292)
Pension and other post- retirement benefits liability			721	306
Foreign currency translation adjustments			66,925	9,305
Other			(164)	37,580
Ending balance	(53,824)	(82,101)	(53,824)	(82,101)
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			368,416	296,053
Net income			13,111	10,304
Pension and other post- retirement benefits liability			(44)
Foreign currency translation adjustments			2,756
Distributions to noncontrolling interests			(16,033)	(8,084)
Ending balance	$ 368,206	$ 298,273	$ 368,206	$ 298,273

Stockholders' Equity (Changes65

Stockholders' Equity (Changes in Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated other comprehensive loss	$ (53,824)		$ (53,824)		$ (121,306)
Other comprehensive income, net of income taxes	49,812	$ 8,562	67,482	$ 47,191
Ending balance	4,209,043	3,737,436	4,209,043	3,737,436
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated other comprehensive loss					(121,306)	$ (129,292)
Other comprehensive income (loss) before reclassifications			66,856	47,603
Amounts reclassified from accumulated other comprehensive loss (income)			626	(412)
Other comprehensive income, net of income taxes			67,482	47,191
Ending balance	(53,824)	(82,101)	(53,824)	(82,101)
Benefits Liability, Net of Tax [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated other comprehensive loss					28,945	(8,607)
Other comprehensive income (loss) before reclassifications			95	(127)
Amounts reclassified from accumulated other comprehensive loss (income)			626	433
Other comprehensive income, net of income taxes			721	306
Ending balance	29,666	(8,301)	29,666	(8,301)
Cumulative Foreign Currency Exchange, Net of Tax [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated other comprehensive loss					(150,202)	(115,690)
Other comprehensive income (loss) before reclassifications			66,925	9,305
Amounts reclassified from accumulated other comprehensive loss (income)			0	0
Other comprehensive income, net of income taxes			66,925	9,305
Ending balance	(83,277)	(106,385)	(83,277)	(106,385)
Net Unrealized Holdings Gains (Losses) on Investments, Net of Tax [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated other comprehensive loss					$ (49)	$ (4,995)
Other comprehensive income (loss) before reclassifications			(164)	38,425
Amounts reclassified from accumulated other comprehensive loss (income)			0	(845)
Other comprehensive income, net of income taxes			(164)	37,580
Ending balance	$ (213)	$ 32,585	$ (213)	$ 32,585

Stockholders' Equity (Reclassif

Stockholders' Equity (Reclassifications in Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Provision for income taxes, investments	$ (68,188)	$ (66,584)	$ (124,071)	$ (135,884)
Benefits Liability, Net of Tax [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	(466)	(369)	(929)	(703)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Tax	140	142	303	270
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax	(326)	(227)	(626)	(433)
Total reclassifications for the period			(626)	(433)
Net Unrealized Holdings Gains on Available-for-sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total reclassifications for the period			0	845
Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total reclassifications for the period	(326)	585	(626)	412
Reclassification out of Accumulated Other Comprehensive Income [Member] | Net Unrealized Holdings Gains on Available-for-sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other income, net	0	1,267	0	1,319
Provision for income taxes, investments	0	(455)	0	(474)
Income (loss), including portion attributable to noncontrolling interest	$ 0	$ 812	$ 0	$ 845

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Aug. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 4,465	$ 2,781	$ 10,768	$ 5,084
Axiall Corporation [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share price (in usd per share)					$ 33

Derivative Instruments (Narrati

Derivative Instruments (Narrative) (Details) - Not Designated as Hedging Instrument [Member] - Commodity Forward Contracts [Member]	6 Months Ended	12 Months Ended
	Jun. 30, 2017MMBTUgal	Dec. 31, 2016MMBTUgal
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume | gal	173,900,000	257,000,000
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	9,100,000	8,500,000

Derivative Instruments (Impact

Derivative Instruments (Impact of Derivative Instruments on Consolidated Balance Sheet) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Commodity Forward Contracts [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 6,351	$ 14,986
Derivative Liability, Fair Value, Gross Liability	(7,630)	(7,221)
Accounts receivable, net [Member]
Derivative [Line Items]
Derivative Asset, Current	2,245	7,589
Derivative Asset, Fair Value, Gross Asset	2,245	7,727
Derivative Liability, Fair Value, Gross Liability	0	(138)
Accounts receivable, net [Member] | Subject to Master Netting [Member]
Derivative [Line Items]
Derivative Asset, Current	0	1,498
Derivative Asset, Fair Value, Gross Asset	0	1,636
Derivative Liability, Fair Value, Gross Liability	0	(138)
Accounts receivable, net [Member] | Not Subject to Master Netting [Member]
Derivative [Line Items]
Derivative Asset, Current	2,245	6,091
Derivative Asset, Fair Value, Gross Asset	2,245	6,091
Derivative Liability, Fair Value, Gross Liability	0	0
Deferred Charges and other assets, net [Member]
Derivative [Line Items]
Derivative Asset, Noncurrent	2,273	5,249
Derivative Asset, Fair Value, Gross Asset	2,273	5,249
Derivative Liability, Fair Value, Gross Liability	0	0
Deferred Charges and other assets, net [Member] | Subject to Master Netting [Member]
Derivative [Line Items]
Derivative Asset, Noncurrent	0	0
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	0	0
Deferred Charges and other assets, net [Member] | Not Subject to Master Netting [Member]
Derivative [Line Items]
Derivative Asset, Noncurrent	2,273	5,249
Derivative Asset, Fair Value, Gross Asset	2,273	5,249
Derivative Liability, Fair Value, Gross Liability	0	0
Accrued Liabilities [Member]
Derivative [Line Items]
Derivative Liability, Current	(1,143)	(1,349)
Derivative Asset, Fair Value, Gross Asset	1,062	0
Derivative Liability, Fair Value, Gross Liability	(2,205)	(1,349)
Accrued Liabilities [Member] | Subject to Master Netting [Member]
Derivative [Line Items]
Derivative Liability, Current	(203)	0
Derivative Asset, Fair Value, Gross Asset	1,062	0
Derivative Liability, Fair Value, Gross Liability	(1,265)	0
Accrued Liabilities [Member] | Not Subject to Master Netting [Member]
Derivative [Line Items]
Derivative Liability, Current	(940)	(1,349)
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	(940)	(1,349)
Other Liabilities [Member]
Derivative [Line Items]
Derivative Liability, Noncurrent	(4,654)	(3,724)
Derivative Asset, Fair Value, Gross Asset	771	2,010
Derivative Liability, Fair Value, Gross Liability	(5,425)	(5,734)
Other Liabilities [Member] | Subject to Master Netting [Member]
Derivative [Line Items]
Derivative Liability, Noncurrent	(1,545)	(436)
Derivative Asset, Fair Value, Gross Asset	771	2,010
Derivative Liability, Fair Value, Gross Liability	(2,316)	(2,446)
Other Liabilities [Member] | Not Subject to Master Netting [Member]
Derivative [Line Items]
Derivative Liability, Noncurrent	(3,109)	(3,288)
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	$ (3,109)	$ (3,288)

Derivative Instruments (Impac70

Derivative Instruments (Impact of Derivative Instruments Not Designated as Fair Value Hedges) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Not Designated as Hedging Instrument [Member] | Cost of Sales [Member] | Commodity Forward Contracts [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (435)	$ 11,567	$ (9,602)	$ 15,624

Fair Value Measurements (Summar

Fair Value Measurements (Summary of Assets and Liabilities Accounted at Fair Value on Recurring Basis) (Details) - Commodity Forward Contracts [Member] - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Risk management assets - Commodity forward contracts	$ 6,351	$ 14,986
Risk management liabilities - Commodity forward contracts	7,630	7,221
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Risk management assets - Commodity forward contracts	6,351	14,986
Risk management liabilities - Commodity forward contracts	(7,630)	(7,221)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Risk management assets - Commodity forward contracts	567	878
Risk management liabilities - Commodity forward contracts	(6,692)	(6,854)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Risk management assets - Commodity forward contracts	5,784	14,108
Risk management liabilities - Commodity forward contracts	$ (938)	$ (367)

Fair Value Measurements (Summ72

Fair Value Measurements (Summary of Carrying and Fair Values of Long Term Debt) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Senior Notes [Member] | 4.625% Senior Notes Due 2021 (New Westlake 2021 Notes) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Maturity	2,021
Stated interest rate (percent)	4.625%		4.625%
Senior Notes [Member] | 4.625% Senior Notes Due 2021 (Existing Axiall 2021 Notes) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Maturity	2,021
Stated interest rate (percent)	4.625%		4.625%
Senior Notes [Member] | 3.60% Senior Notes Due 2022 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Maturity	2,022
Stated interest rate (percent)	3.60%
Senior Notes [Member] | 4.875% Senior Notes Due 2023 (New Westlake 2023 Notes) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Maturity	2,023
Stated interest rate (percent)	4.875%		4.875%
Senior Notes [Member] | 4.875% Senior Notes Due 2023 (Existing Axiall 2023 Notes) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Maturity	2,023
Stated interest rate (percent)	4.875%		4.875%
Senior Notes [Member] | 3.6% Senior Notes Due 2026 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Maturity	2,026
Stated interest rate (percent)	3.60%
Senior Notes [Member] | Loan related to tax-exempt waste disposal revenue bonds due 2027 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Maturity	2,027
Senior Notes [Member] | 6 1/2% Senior Notes Due 2029 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Maturity	2,029
Stated interest rate (percent)	6.50%
Senior Notes [Member] | 6 3/4% Senior Notes Due 2032 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Maturity	2,032
Stated interest rate (percent)	6.75%
Senior Notes [Member] | 2035 GO Zone 6 1/2% Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Maturity	2,035
Stated interest rate (percent)	6.50%
Senior Notes [Member] | 2035 IKE Zone 6 1/2% Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Maturity	2,035
Stated interest rate (percent)	6.50%
Senior Notes [Member] | 5% Senior Notes Due 2046 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Maturity	2,046
Stated interest rate (percent)	5.00%
Carrying Value [Member] | Line of Credit [Member] | Unsecured Revolving Credit Facility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revolving credit facility	$ 140,000	$ 325,000
Carrying Value [Member] | Senior Notes [Member] | 4.625% Senior Notes Due 2021 (New Westlake 2021 Notes) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	648,295	651,630
Carrying Value [Member] | Senior Notes [Member] | 4.625% Senior Notes Due 2021 (Existing Axiall 2021 Notes) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	65,725	66,069
Carrying Value [Member] | Senior Notes [Member] | 3.60% Senior Notes Due 2022 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	248,280	248,109
Carrying Value [Member] | Senior Notes [Member] | 4.875% Senior Notes Due 2023 (New Westlake 2023 Notes) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	446,109	447,224
Carrying Value [Member] | Senior Notes [Member] | 4.875% Senior Notes Due 2023 (Existing Axiall 2023 Notes) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	16,705	16,747
Carrying Value [Member] | Senior Notes [Member] | 3.6% Senior Notes Due 2026 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	739,688	739,243
Carrying Value [Member] | Senior Notes [Member] | 6 1/2% Senior Notes Due 2029 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	99,120	99,084
Carrying Value [Member] | Senior Notes [Member] | 6 3/4% Senior Notes Due 2032 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	248,176	248,117
Carrying Value [Member] | Senior Notes [Member] | 2035 GO Zone 6 1/2% Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	88,183	88,161
Carrying Value [Member] | Senior Notes [Member] | 2035 IKE Zone 6 1/2% Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	64,414	64,398
Carrying Value [Member] | Senior Notes [Member] | 5% Senior Notes Due 2046 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	674,316	673,983
Carrying Value [Member] | Loan related to tax-exempt waste disposal revenue bonds due 2027 [Member] | Loan related to tax-exempt waste disposal revenue bonds due 2027 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	10,889	10,889
Fair Value [Member] | Line of Credit [Member] | Unsecured Revolving Credit Facility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revolving credit facility	140,000	325,000
Fair Value [Member] | Senior Notes [Member] | 4.625% Senior Notes Due 2021 (New Westlake 2021 Notes) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	649,054	650,847
Fair Value [Member] | Senior Notes [Member] | 4.625% Senior Notes Due 2021 (Existing Axiall 2021 Notes) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	65,930	65,775
Fair Value [Member] | Senior Notes [Member] | 3.60% Senior Notes Due 2022 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	255,255	251,725
Fair Value [Member] | Senior Notes [Member] | 4.875% Senior Notes Due 2023 (New Westlake 2023 Notes) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	453,092	451,301
Fair Value [Member] | Senior Notes [Member] | 4.875% Senior Notes Due 2023 (Existing Axiall 2023 Notes) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	16,923	16,501
Fair Value [Member] | Senior Notes [Member] | 3.6% Senior Notes Due 2026 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	744,946	722,055
Fair Value [Member] | Senior Notes [Member] | 6 1/2% Senior Notes Due 2029 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	113,358	112,433
Fair Value [Member] | Senior Notes [Member] | 6 3/4% Senior Notes Due 2032 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	254,100	258,818
Fair Value [Member] | Senior Notes [Member] | 2035 GO Zone 6 1/2% Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	101,589	100,323
Fair Value [Member] | Senior Notes [Member] | 2035 IKE Zone 6 1/2% Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	74,190	73,270
Fair Value [Member] | Senior Notes [Member] | 5% Senior Notes Due 2046 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	741,265	691,712
Fair Value [Member] | Loan related to tax-exempt waste disposal revenue bonds due 2027 [Member] | Loan related to tax-exempt waste disposal revenue bonds due 2027 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	$ 10,889	$ 10,889

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate	30.00%	36.50%	29.00%	35.70%
U.S. federal statutory income tax rate	35.00%	35.00%	35.00%	35.00%

Earnings per Share (Schedule of

Earnings per Share (Schedule of Net Income Attributable to Common Stockholders) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net income attributable to Westlake Chemical Corporation	$ 152,827	$ 111,124	$ 291,017	$ 234,252
Net income attributable to participating securities	(819)	(504)	(1,513)	(1,054)
Net income attributable to common shareholders	$ 152,008	$ 110,620	$ 289,504	$ 233,198

Earnings per Share (Reconciliat

Earnings per Share (Reconciliation of Denominator for Basic and Diluted Earnings Per Share) (Details) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Weighted average common shares—basic	129,051,227	129,583,224	129,015,507	129,886,594
Incremental Shares From Assumed exercise of options	735,487	397,303	724,136	403,927
Weighted average common shares-diluted	129,786,714	129,980,527	129,739,643	130,290,521
Earnings per share attributable to Westlake Chemical Corporation: Basic	$ 1.18	$ 0.85	$ 2.24	$ 1.80
Earnings per share attributable to Westlake Chemical Corporation: Diluted	$ 1.17	$ 0.85	$ 2.23	$ 1.79

Earnings per Share (Additional

Earnings per Share (Additional Information) (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Number of options excluded from computation of diluted earnings per share	583,585	695,040	511,085	625,494

Supplemental Information (Detai

Supplemental Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Accrued Liabilities [Abstract]
Accrued liabilities	$ 447,412		$ 537,483
Accrued rebates	84,088		77,985
Accrued Liabilities Affiliates	11,203		$ 10,551
Increase (Decrease) in Capital Expenditure Accrual	$ 10,848	$ 50,326

Commitments and Contingencies (

Commitments and Contingencies (Additional Information) (Detail) $ in Thousands	1 Months Ended	6 Months Ended	12 Months Ended
	Oct. 31, 2016USD ($)	Jun. 30, 2017USD ($)settlement	Dec. 31, 2015USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2016USD ($)
Environmental Loss Contingencies [Line Items]
Environmental Loss contingency accrual		$ 47,669			$ 48,817
Pending Litigation [Member]
Environmental Loss Contingencies [Line Items]
Maximum Expected Damages	$ 167
LDEQ [Member] | Settled Litigation [Member]
Environmental Loss Contingencies [Line Items]
Number of claims settled | settlement		2
Amount of settlement for compliance violations		$ 192
LDEQ [Member] | Pending Litigation [Member]
Environmental Loss Contingencies [Line Items]
Maximum Expected Damages		100
Natrium [Member] | Axiall Corporation [Member] | Settled Litigation [Member]
Environmental Loss Contingencies [Line Items]
Payments for environmental loss contingencies				$ 449
Lake Charles, Louisiana [Member] | Axiall Corporation [Member] | Environmental Protection Agency [Member] | Settled Litigation [Member]
Environmental Loss Contingencies [Line Items]
Amount of settlement for compliance violations			$ (878)
Maximum [Member]
Environmental Loss Contingencies [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss		80,000
Minimum [Member]
Environmental Loss Contingencies [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss		40,000
Unfavorable Regulatory Action [Member] | Culvert City, Kentucky and Lakes Charles, Louisiana [Member] | Environmental Protection Agency [Member] | Pending Litigation [Member]
Environmental Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss		$ 100

Segment Information (Additional

Segment Information (Additional Information) (Detail)	6 Months Ended
	Jun. 30, 2017Segment
Segment Reporting [Abstract]
Number of segments	2

Segment Information (Sales) (De

Segment Information (Sales) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Net external sales	$ 1,979,161	$ 1,086,061	$ 3,921,777	$ 2,061,248
Income (loss) from operations	267,116	179,938	502,414	382,214
Depreciation and amortization	144,630	67,250	294,899	132,964
Other income (expense), net	(538)	8,181	4,533	10,826
Provision for (benefit from) income taxes	68,188	66,584	124,071	135,884
Capital expenditures	146,617	150,833	280,902	287,160
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net external sales	1,979,161	1,086,061	3,921,777	2,061,248
Operating Segments [Member] | Olefins [Member]
Segment Reporting Information [Line Items]
Net external sales	489,234	494,484	1,032,229	925,504
Income (loss) from operations	143,277	140,564	323,095	289,799
Depreciation and amortization	35,175	30,236	76,215	58,933
Other income (expense), net	588	1,093	1,738	2,606
Provision for (benefit from) income taxes	36,453	51,940	94,264	104,473
Capital expenditures	23,733	93,739	49,083	188,890
Operating Segments [Member] | Vinyls [Member]
Segment Reporting Information [Line Items]
Net external sales	1,489,927	591,577	2,889,548	1,135,744
Income (loss) from operations	143,320	52,208	214,761	114,324
Depreciation and amortization	106,822	36,268	214,095	72,555
Other income (expense), net	(1,534)	4,466	2,058	2,949
Provision for (benefit from) income taxes	39,237	16,297	54,195	33,567
Capital expenditures	114,372	56,613	222,454	96,869
Operating Segments [Member] | Polyethylene [Member] | Olefins [Member]
Segment Reporting Information [Line Items]
Net external sales	358,392	371,658	744,334	717,690
Operating Segments [Member] | Styrene, Feedstock And Other [Member] | Olefins [Member]
Segment Reporting Information [Line Items]
Net external sales	130,842	122,826	287,895	207,814
Operating Segments [Member] | PVC, Caustic Soda And Other [Member] | Vinyls [Member]
Segment Reporting Information [Line Items]
Net external sales	1,157,317	462,472	2,288,446	893,374
Operating Segments [Member] | Building Products [Member] | Vinyls [Member]
Segment Reporting Information [Line Items]
Net external sales	332,610	129,105	601,102	242,370
Corporate and other [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	(19,481)	(12,834)	(35,442)	(21,909)
Depreciation and amortization	2,633	746	4,589	1,476
Other income (expense), net	408	2,622	737	5,271
Provision for (benefit from) income taxes	(7,502)	(1,653)	(24,388)	(2,156)
Capital expenditures	8,512	481	9,365	1,401
Intersegment sales [Member]
Segment Reporting Information [Line Items]
Net external sales	98,311	27,518	184,547	55,831
Intersegment sales [Member] | Olefins [Member]
Segment Reporting Information [Line Items]
Net external sales	97,992	27,293	183,936	55,242
Intersegment sales [Member] | Vinyls [Member]
Segment Reporting Information [Line Items]
Net external sales	$ 319	$ 225	$ 611	$ 589

Segment Information (Reconcilia

Segment Information (Reconciliation of Total Segment Income from Operations to Consolidated Income before Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting [Abstract]
Income from operations	$ 267,116	$ 179,938	$ 502,414	$ 382,214
Interest Expense	(38,972)	(5,915)	(78,748)	(12,600)
Other income (expense), net	(538)	8,181	4,533	10,826
Income before income taxes	$ 227,606	$ 182,204	$ 428,199	$ 380,440

Segment Information (Total Asse

Segment Information (Total Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 10,885,707	$ 10,890,253
Operating Segments [Member] | Olefins [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,077,986	2,092,617
Operating Segments [Member] | Vinyls [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	8,379,465	8,287,204
Corporate and other [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 428,256	$ 510,432

Guarantor Disclosures (Addition

Guarantor Disclosures (Additional Information) (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2017USD ($)
Condensed Financial Statements, Captions [Line Items]
Equity Method Investment, Ownership Percentage	100.00%
3.60%, 5.0%, 4.625%, 4.875% Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Minimum debt amount guaranteed by subsidiaries	$ 5,000
3.60% Senior Notes Due 2022 [Member] | Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Debt Instrument Maturity	2,022
3.6% Senior Notes Due 2026 [Member] | Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Debt Instrument Maturity	2,026
5% Senior Notes Due 2046 [Member] | Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Debt Instrument Maturity	2,046
4.625% Senior Notes Due 2021 (New Westlake 2021 Notes) [Member] | Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Debt Instrument Maturity	2,021
4.875% Senior Notes Due 2023 (New Westlake 2023 Notes) [Member] | Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Debt Instrument Maturity	2,023

Guarantor Disclosures (Condense

Guarantor Disclosures (Condensed Consolidating Financial Information Balance Sheets) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 395,776	$ 459,453	$ 770,997	$ 662,525
Accounts receivable, net	1,095,808	938,743
Inventories	831,700	801,100
Prepaid expenses and other current assets	45,744	48,493
Restricted cash	8,607	160,527
Total current assets	2,377,635	2,408,316
Property, plant and equipment, net	6,316,731	6,420,062
Goodwill	999,614	946,553
Customer relationships, net	654,092	611,615
Other intangible assets, net	169,991	175,839
Deferred charges and other assets, net	367,644	327,868
Total other assets, net	2,191,341	2,061,875
Total assets	10,885,707	10,890,253
Accounts payable	583,509	496,259
Accrued liabilities	447,412	537,483
Term loan	0	149,341
Total current liabilities	1,030,921	1,183,083
Long-term debt, net	3,489,900	3,678,654
Deferred income taxes	1,648,529	1,650,575
Pension and other liabilities	507,314	485,896
Total liabilities	6,676,664	6,998,208
Total Westlake Chemical Corporation stockholders' equity	3,840,837	3,523,629
Noncontrolling interests	368,206	368,416
Total equity	4,209,043	3,892,045	3,737,436	3,561,931
Total liabilities and equity	10,885,707	10,890,253
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	(5,796,207)	(4,832,599)
Inventories	0	0
Prepaid expenses and other current assets	(79,548)	(36,504)
Restricted cash	0	0
Total current assets	(5,875,755)	(4,869,103)
Property, plant and equipment, net	0	0
Goodwill	0	0
Customer relationships, net	0	0
Other intangible assets, net	0	(25,581)
Deferred charges and other assets, net	(11,516,321)	(10,832,054)
Total other assets, net	(11,516,321)	(10,857,635)
Total assets	(17,392,076)	(15,726,738)
Accounts payable	(5,758,697)	(4,807,780)
Accrued liabilities	(117,058)	(61,323)
Term loan		0
Total current liabilities	(5,875,755)	(4,869,103)
Long-term debt, net	(4,865,637)	(3,997,070)
Deferred income taxes	(22,985)	(22,494)
Pension and other liabilities	0	0
Total liabilities	(10,764,377)	(8,888,667)
Total Westlake Chemical Corporation stockholders' equity	(6,627,699)	(6,838,071)
Noncontrolling interests	0	0
Total equity	(6,627,699)	(6,838,071)
Total liabilities and equity	(17,392,076)	(15,726,738)
Westlake Chemical Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	49,366	146,990	412,881	303,131
Accounts receivable, net	2,742,556	2,117,540
Inventories	0	0
Prepaid expenses and other current assets	75,730	30,748
Restricted cash	0	0
Total current assets	2,867,652	2,295,278
Property, plant and equipment, net	0	0
Goodwill	0	0
Customer relationships, net	0	0
Other intangible assets, net	0	0
Deferred charges and other assets, net	9,552,799	9,170,042
Total other assets, net	9,552,799	9,170,042
Total assets	12,420,451	11,465,320
Accounts payable	5,183,033	4,330,375
Accrued liabilities	0	26,367
Term loan		0
Total current liabilities	5,183,033	4,356,742
Long-term debt, net	3,396,581	3,584,949
Deferred income taxes	0	0
Pension and other liabilities	0	0
Total liabilities	8,579,614	7,941,691
Total Westlake Chemical Corporation stockholders' equity	3,840,837	3,523,629
Noncontrolling interests	0	0
Total equity	3,840,837	3,523,629
Total liabilities and equity	12,420,451	11,465,320
100% Owned Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	15,399	53,006	1,084	6,818
Accounts receivable, net	3,785,141	3,329,871
Inventories	631,802	597,819
Prepaid expenses and other current assets	40,213	41,755
Restricted cash	1,500	0
Total current assets	4,474,055	4,022,451
Property, plant and equipment, net	4,326,202	4,475,943
Goodwill	847,816	791,706
Customer relationships, net	509,933	468,645
Other intangible assets, net	97,224	130,243
Deferred charges and other assets, net	790,393	874,003
Total other assets, net	2,245,366	2,264,597
Total assets	11,045,623	10,762,991
Accounts payable	815,642	748,364
Accrued liabilities	355,132	389,216
Term loan		0
Total current liabilities	1,170,774	1,137,580
Long-term debt, net	4,537,551	4,090,775
Deferred income taxes	1,573,733	1,581,260
Pension and other liabilities	365,170	360,622
Total liabilities	7,647,228	7,170,237
Total Westlake Chemical Corporation stockholders' equity	3,398,395	3,592,754
Noncontrolling interests	0	0
Total equity	3,398,395	3,592,754
Total liabilities and equity	11,045,623	10,762,991
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	331,011	259,457	$ 357,032	$ 352,576
Accounts receivable, net	364,318	323,931
Inventories	199,898	203,281
Prepaid expenses and other current assets	9,349	12,494
Restricted cash	7,107	160,527
Total current assets	911,683	959,690
Property, plant and equipment, net	1,990,529	1,944,119
Goodwill	151,798	154,847
Customer relationships, net	144,159	142,970
Other intangible assets, net	72,767	71,177
Deferred charges and other assets, net	1,540,773	1,115,877
Total other assets, net	1,909,497	1,484,871
Total assets	4,811,709	4,388,680
Accounts payable	343,531	225,300
Accrued liabilities	209,338	183,223
Term loan		149,341
Total current liabilities	552,869	557,864
Long-term debt, net	421,405	0
Deferred income taxes	97,781	91,809
Pension and other liabilities	142,144	125,274
Total liabilities	1,214,199	774,947
Total Westlake Chemical Corporation stockholders' equity	3,229,304	3,245,317
Noncontrolling interests	368,206	368,416
Total equity	3,597,510	3,613,733
Total liabilities and equity	$ 4,811,709	$ 4,388,680

Guarantor Disclosures (Conden85

Guarantor Disclosures (Condensed Consolidating Financial Information Statement of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,979,161	$ 1,086,061	$ 3,921,777	$ 2,061,248
Cost of sales	1,573,327	844,695	3,148,800	1,564,297
Gross profit	405,834	241,366	772,977	496,951
Selling, general and administrative expenses	130,626	61,428	254,277	114,737
Transaction and integration-related costs	8,092	7,709	16,286	7,709
Income (loss) from operations	267,116	179,938	502,414	382,214
Interest Expense	(38,972)	(5,915)	(78,748)	(12,600)
Other income (expense), net	(538)	8,181	4,533	10,826
Income before income taxes	227,606	182,204	428,199	380,440
Provision for (benefit from) income taxes	68,188	66,584	124,071	135,884
Equity in net income of subsidiaries	0	0	0	0
Net income	159,418	115,620	304,128	244,556
Net income attributable to noncontrolling interests	6,591	4,496	13,111	10,304
Net income attributable to Westlake Chemical Corporation	152,827	111,124	291,017	234,252
Comprehensive income attributable to Westlake Chemical Corporation	203,090	119,686	355,787	281,443
Westlake Chemical Corporation [Member]
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	142	950	919	1,557
Transaction and integration-related costs	0		0
Income (loss) from operations	(142)	(950)	(919)	(1,557)
Interest Expense	(38,160)	(11,151)	(76,345)	(21,563)
Other income (expense), net	37,282	4,050	74,439	5,865
Income before income taxes	(1,020)	(8,051)	(2,825)	(17,255)
Provision for (benefit from) income taxes	4,616	(2,960)	(851)	(6,182)
Equity in net income of subsidiaries	158,463	116,215	292,991	245,325
Net income	152,827	111,124	291,017	234,252
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to Westlake Chemical Corporation	152,827	111,124	291,017	234,252
Comprehensive income attributable to Westlake Chemical Corporation	203,090	119,686	355,787	281,443
100% Owned Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	1,596,952	820,190	3,176,677	1,581,931
Cost of sales	1,346,983	698,096	2,706,258	1,340,833
Gross profit	249,969	122,094	470,419	241,098
Selling, general and administrative expenses	95,845	44,020	188,109	81,017
Transaction and integration-related costs	8,092		16,224
Income (loss) from operations	146,032	78,074	266,086	160,081
Interest Expense	(45,783)	(5,686)	(91,460)	(12,471)
Other income (expense), net	3,550	(1,183)	3,293	(75)
Income before income taxes	103,799	71,205	177,919	147,535
Provision for (benefit from) income taxes	52,083	55,671	105,455	117,874
Equity in net income of subsidiaries	0	0	0	0
Net income	51,716	15,534	72,464	29,661
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to Westlake Chemical Corporation	51,716	15,534	72,464	29,661
Comprehensive income attributable to Westlake Chemical Corporation	51,776	15,634	72,449	29,967
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	804,002	553,173	1,540,087	1,122,992
Cost of sales	641,349	428,898	1,224,009	856,668
Gross profit	162,653	124,275	316,078	266,324
Selling, general and administrative expenses	41,427	21,461	78,769	42,634
Transaction and integration-related costs	0		62
Income (loss) from operations	121,226	102,814	237,247	223,690
Interest Expense	(34)	(205)	(840)	(459)
Other income (expense), net	3,635	16,441	16,698	26,929
Income before income taxes	124,827	119,050	253,105	250,160
Provision for (benefit from) income taxes	11,489	13,873	19,467	24,192
Equity in net income of subsidiaries	0	0	0	0
Net income	113,338	105,177	233,638	225,968
Net income attributable to noncontrolling interests	6,591	4,496	13,111	10,304
Net income attributable to Westlake Chemical Corporation	106,747	100,681	220,527	215,664
Comprehensive income attributable to Westlake Chemical Corporation	148,417	102,296	259,034	254,514
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	(421,793)	(287,302)	(794,987)	(643,675)
Cost of sales	(415,005)	(282,299)	(781,467)	(633,204)
Gross profit	(6,788)	(5,003)	(13,520)	(10,471)
Selling, general and administrative expenses	(6,788)	(5,003)	(13,520)	(10,471)
Transaction and integration-related costs	0		0
Income (loss) from operations	0	0	0	0
Interest Expense	45,005	11,127	89,897	21,893
Other income (expense), net	(45,005)	(11,127)	(89,897)	(21,893)
Income before income taxes	0	0	0	0
Provision for (benefit from) income taxes	0	0	0	0
Equity in net income of subsidiaries	(158,463)	(116,215)	(292,991)	(245,325)
Net income	(158,463)	(116,215)	(292,991)	(245,325)
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to Westlake Chemical Corporation	(158,463)	(116,215)	(292,991)	(245,325)
Comprehensive income attributable to Westlake Chemical Corporation	$ (200,193)	$ (117,930)	$ (331,483)	$ (284,481)

Guarantor Disclosures (Conden86

Guarantor Disclosures (Condensed Consolidating Financial Information Statement of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Condensed Financial Statements, Captions [Line Items]
Net income	$ 159,418	$ 115,620	$ 304,128	$ 244,556
Depreciation and amortization	144,630	67,250	294,899	132,964
Deferred income taxes			14,962	102,990
Net changes in working capital and other			(134,275)	(110,618)
Net cash provided by (used for) operating activities			479,714	369,892
Additions to property, plant and equipment	(146,617)	(150,833)	(280,902)	(287,160)
Additions to cost method investment			(31,000)	0
Proceeds from disposition of assets			133	105
Proceeds from involuntary conversion of assets			1,672	0
Proceeds from sales and maturities of securities			0	302,432
Purchase of securities			0	(138,422)
Settlements of derivative instruments			(376)	(3,372)
Net cash used for investing activities			(310,473)	(126,417)
Intercompany financing			0	0
Debt issuance costs			(376)	(9,700)
Dividends paid			(49,315)	(47,317)
Distributions to noncontrolling interests			(16,033)	(8,084)
Proceeds from issuance of notes payable			3,544	3,842
Proceeds from drawdown of revolver			175,000	0
Restricted cash associated with term loan			154,000	0
Repayment of term loan			(150,000)	0
Repayment of notes payable			(4,901)	(8,626)
Repayment of revolver			(360,000)	0
Other, net			1,101	800
Repurchase of common stock for treasury			0	(67,404)
Net cash provided by (used for) financing activities			(246,604)	(136,489)
Effect of exchange rate changes on cash and cash equivalents			13,686	1,486
Net increase (decrease) in cash and cash equivalents			(63,677)	108,472
Cash and cash equivalents at beginning of period			459,453	662,525
Cash and cash equivalents at end of period	395,776	770,997	395,776	770,997
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	(158,463)	(116,215)	(292,991)	(245,325)
Depreciation and amortization			0	0
Deferred income taxes			0	0
Net changes in working capital and other			292,991	245,325
Net cash provided by (used for) operating activities			0	0
Additions to property, plant and equipment			0	0
Additions to cost method investment			0
Proceeds from disposition of assets			0	0
Proceeds from involuntary conversion of assets			0
Proceeds from sales and maturities of securities				0
Purchase of securities				0
Settlements of derivative instruments			0	0
Net cash used for investing activities			0	0
Intercompany financing			0	0
Debt issuance costs				0
Dividends paid			0	0
Distributions to noncontrolling interests			0	0
Proceeds from issuance of notes payable			0	0
Proceeds from drawdown of revolver			0
Restricted cash associated with term loan			0
Repayment of term loan			0
Repayment of notes payable			0	0
Repayment of revolver			0
Other, net			0	0
Repurchase of common stock for treasury				0
Net cash provided by (used for) financing activities			0	0
Effect of exchange rate changes on cash and cash equivalents			0
Net increase (decrease) in cash and cash equivalents			0	0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	0	0	0	0
Westlake Chemical Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	152,827	111,124	291,017	234,252
Depreciation and amortization			0	0
Deferred income taxes			(126)	(4,802)
Net changes in working capital and other			(400,511)	(274,585)
Net cash provided by (used for) operating activities			(109,620)	(45,135)
Additions to property, plant and equipment			0	0
Additions to cost method investment			0
Proceeds from disposition of assets			0	0
Proceeds from involuntary conversion of assets			0
Proceeds from sales and maturities of securities				302,432
Purchase of securities				(130,830)
Settlements of derivative instruments			0	0
Net cash used for investing activities			0	171,602
Intercompany financing			241,210	106,904
Debt issuance costs				(9,700)
Dividends paid			(49,315)	(47,317)
Distributions to noncontrolling interests			0	0
Proceeds from issuance of notes payable			0	0
Proceeds from drawdown of revolver			175,000
Restricted cash associated with term loan			154,000
Repayment of term loan			(150,000)
Repayment of notes payable			0	0
Repayment of revolver			(360,000)
Other, net			1,101	800
Repurchase of common stock for treasury				(67,404)
Net cash provided by (used for) financing activities			11,996	(16,717)
Effect of exchange rate changes on cash and cash equivalents			0	0
Net increase (decrease) in cash and cash equivalents			(97,624)	109,750
Cash and cash equivalents at beginning of period			146,990	303,131
Cash and cash equivalents at end of period	49,366	412,881	49,366	412,881
100% Owned Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	51,716	15,534	72,464	29,661
Depreciation and amortization			193,594	66,137
Deferred income taxes			15,207	96,990
Net changes in working capital and other			(25,601)	(38,234)
Net cash provided by (used for) operating activities			255,664	154,554
Additions to property, plant and equipment			(198,621)	(94,775)
Additions to cost method investment			(31,000)
Proceeds from disposition of assets			3	7
Proceeds from involuntary conversion of assets			1,672
Proceeds from sales and maturities of securities				0
Purchase of securities				(7,592)
Settlements of derivative instruments			(376)	(3,372)
Net cash used for investing activities			(228,322)	(105,732)
Intercompany financing			(253,075)	(212,948)
Debt issuance costs				0
Dividends paid			0	0
Distributions to noncontrolling interests			188,646	158,392
Proceeds from issuance of notes payable			0	0
Proceeds from drawdown of revolver			0
Restricted cash associated with term loan			0
Repayment of term loan			0
Repayment of notes payable			(520)	0
Repayment of revolver			0
Other, net			0	0
Repurchase of common stock for treasury				0
Net cash provided by (used for) financing activities			(64,949)	(54,556)
Effect of exchange rate changes on cash and cash equivalents			0	0
Net increase (decrease) in cash and cash equivalents			(37,607)	(5,734)
Cash and cash equivalents at beginning of period			53,006	6,818
Cash and cash equivalents at end of period	15,399	1,084	15,399	1,084
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	113,338	105,177	233,638	225,968
Depreciation and amortization			101,305	66,827
Deferred income taxes			(119)	10,802
Net changes in working capital and other			(1,154)	(43,124)
Net cash provided by (used for) operating activities			333,670	260,473
Additions to property, plant and equipment			(82,281)	(192,385)
Additions to cost method investment			0
Proceeds from disposition of assets			130	98
Proceeds from involuntary conversion of assets			0
Proceeds from sales and maturities of securities				0
Purchase of securities				0
Settlements of derivative instruments			0	0
Net cash used for investing activities			(82,151)	(192,287)
Intercompany financing			11,865	106,044
Debt issuance costs				0
Dividends paid			0	0
Distributions to noncontrolling interests			(204,679)	(166,476)
Proceeds from issuance of notes payable			3,544	3,842
Proceeds from drawdown of revolver			0
Restricted cash associated with term loan			0
Repayment of term loan			0
Repayment of notes payable			(4,381)	(8,626)
Repayment of revolver			0
Other, net			0	0
Repurchase of common stock for treasury				0
Net cash provided by (used for) financing activities			(193,651)	(65,216)
Effect of exchange rate changes on cash and cash equivalents			13,686	1,486
Net increase (decrease) in cash and cash equivalents			71,554	4,456
Cash and cash equivalents at beginning of period			259,457	352,576
Cash and cash equivalents at end of period	$ 331,011	$ 357,032	$ 331,011	$ 357,032