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

No definition available.

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

- Definition

The average effective interest rate during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

Reference 2: 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(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- 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

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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

+ 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 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Line of Credit Facility, Collateral, Percent of Membership Interests

+ References

No definition available.

+ Details

Name:	wlk_LineofCreditFacilityCollateralPercentofMembershipInterests
Namespace Prefix:	wlk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Covenant Terms, Increase In Restricted Cash Based on Non-U.S. Dollar based Deposits, Percent

+ References

No definition available.

+ Details

Name:	wlk_LineofCreditFacilityCovenantTermsIncreaseInRestrictedCashBasedonNonU.S.DollarbasedDepositsPercent
Namespace Prefix:	wlk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Covenant Terms, Period to Increase Bank Deposits

+ References

No definition available.

+ Details

Name:	wlk_LineofCreditFacilityCovenantTermsPeriodtoIncreaseBankDeposits
Namespace Prefix:	wlk_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wlk_TermLoanFacilityMaturingMarch312017Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=wlk_BankofAmericaN.A.Member
Namespace Prefix:
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Balance Type:
Period Type:

Term Loan (Narrative) (Details) - USD ($)		2 Months Ended
Term Loan (Narrative) (Details) - USD ($)	Aug. 10, 2016	Sep. 30, 2016	Sep. 10, 2016	Sep. 09, 2016	Dec. 31, 2015
Line of Credit Facility [Line Items]
Restricted cash		$ 195,705,000			$ 0
Line of Credit [Member] \| Term Loan Facility Maturing March 31, 2017 [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 150,000,000
Interest rate on outstanding term loan		2.82%
Restricted cash	$ 150,000,000
Percent increase In restricted cash based on non-u.s. dollar based deposits	5.00%
Percent of pledged membership interests	65.00%
Line of Credit [Member] \| Term Loan Facility Maturing March 31, 2017 [Member] \| LIBOR [Member]
Line of Credit Facility [Line Items]
Percentage added to basis to find interest rate	2.00%
Line of Credit [Member] \| Term Loan Facility Maturing March 31, 2017 [Member] \| Base Rate [Member]
Line of Credit Facility [Line Items]
Percentage added to basis to find interest rate	1.00%
Line of Credit [Member] \| Term Loan Facility Maturing March 31, 2017 [Member] \| Bank of America, N.A. [Member]
Line of Credit Facility [Line Items]
Restricted cash			$ 75,000,000	$ 50,000,000
Period to increase bank deposits	30 days