Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The effective interest rate at the end of the reporting period.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The permitted amount the line of credit facility may be increased by, under certain circumstances if certain lenders agree to commit to such an increase.

+ References

No definition available.

+ Details

Name:	wlk_LineOfCreditFacilityPermittedIncrease
Namespace Prefix:	wlk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

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- Details

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Balance Type:
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- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

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- Details

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Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
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- Details

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Long-Term Debt (Revolving Credit Facility) (Details) - USD ($)	Sep. 30, 2016	Aug. 23, 2016	Jul. 21, 2016	Aug. 22, 2016	Dec. 31, 2015
Line of Credit Facility [Line Items]
Principal amount	$ 3,677,889,000				$ 764,889,000
Line of Credit [Member]
Line of Credit Facility [Line Items]
Term of revolving credit facility			5 years
Line of Credit [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Increase in credit facility borrowings		$ 25,000,000
Line of Credit [Member] \| Maximum {Member]
Line of Credit Facility [Line Items]
Increase in credit facility borrowings		$ 500,000,000
Line of Credit [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 1,000,000,000
Revolving credit facility, amount outstanding	$ 325,000,000
Line of Credit Facility, Interest Rate at Period End	2.05%
Letters of credit outstanding	$ 76,581,000
Remaining borrowing capacity	$ 598,419,000
Line of Credit [Member] \| Revolving Credit Facility [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Percentage of commitment on borrowing availability	0.10%
Line of Credit [Member] \| Revolving Credit Facility [Member] \| Maximum {Member]
Line of Credit Facility [Line Items]
Percentage of commitment on borrowing availability	0.25%
Line of Credit [Member] \| Revolving Credit Facility [Member] \| LIBOR [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Percentage added to basis to find interest rate	1.00%
Line of Credit [Member] \| Revolving Credit Facility [Member] \| LIBOR [Member] \| Maximum {Member]
Line of Credit Facility [Line Items]
Percentage added to basis to find interest rate	1.75%
Line of Credit [Member] \| Revolving Credit Facility [Member] \| Base Rate [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Percentage added to basis to find interest rate	0.00%
Line of Credit [Member] \| Revolving Credit Facility [Member] \| Base Rate [Member] \| Maximum {Member]
Line of Credit Facility [Line Items]
Percentage added to basis to find interest rate	0.75%
Line of Credit [Member] \| Senior Secured Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity				$ 400,000,000
Line of Credit [Member] \| Letter of Credit [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity			150,000,000
Line of Credit [Member] \| Bridge Loan [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 50,000,000