Long-Term Debt (Senior Secured Revolving Credit Facility) (Details) (Senior Secured Revolving Credit Facility [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 400,000
Percentage of commitment on borrowing availability	0.375%
Remaining borrowing capacity	384,285
Letters of credit outstanding	15,715
Amounts drawn under the facility limited to accounts receivable, percentage	85.00%
Amounts drawn under the facility limited to eligible inventory, percentage	70.00%
Amounts drawn under the facility limited to lesser of eligible inventory orderly liquidation, percentage	85.00%
Amounts drawn under the facility limited to cash held in an account with the agent	100.00%
Advances on inventory, maximum	325,000
Sub-limit for letters of credit facility	400,000
Minimum [Member]
Debt Instrument [Line Items]
Fixed charge coverage ratio for debt covenant	1.0
Minimum [Member] \| Plus LIBOR [Member]
Debt Instrument [Line Items]
Percentage added to basis to find interest rate	1.75%
Minimum [Member] \| Plus Base Rate [Member]
Debt Instrument [Line Items]
Percentage added to basis to find interest rate	0.25%
Minimum [Member] \| Debt Covenant [Member]
Debt Instrument [Line Items]
Fixed charge coverage ratio for debt covenant	1.0
Borrowing availability compliance requirements for credit facility	12.50%
Borrowing availability compliance requirments for credit facility	50,000
Maximum [Member]
Debt Instrument [Line Items]
Increase in credit facility borrowings	150,000
Maximum [Member] \| Plus LIBOR [Member]
Debt Instrument [Line Items]
Percentage added to basis to find interest rate	2.25%
Maximum [Member] \| Plus Base Rate [Member]
Debt Instrument [Line Items]
Percentage added to basis to find interest rate	0.75%
Minimum Increment [Member]
Debt Instrument [Line Items]
Increase in credit facility borrowings	$ 25,000

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

No definition available.

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

- Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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

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 Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

Reference 3: 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

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
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

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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 210.5-02.19(b),22(b))

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

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
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

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

- Definition

The borrowing availability of the line of credit facility, expressed as a percentage of the commitments under the facility, which may trigger additional compliance requirements for the credit facility.

+ References

No definition available.

+ Details

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

- Definition

The calculated fixed charge coverage ratio for the revolving credit facility.

+ References

No definition available.

+ Details

Name:	wlk_FixedChargeCoverageRatioRevolver
Namespace Prefix:	wlk_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Letter of credit sub-limit under the revolving credit facility.

+ References

No definition available.

+ Details

Name:	wlk_LetterOfCreditFacilitySublimit
Namespace Prefix:	wlk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents a percentage, that when multiplied by the net amount of eligible accounts receivable, becomes a factor used in the calculation to determine the borrowing capacity of the revolving credit facility.

+ References

No definition available.

+ Details

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

- Definition

Represents a percentage, that when multiplied by the cash held in account with an agent and subject to a control agreement with that agent, becomes a factor used in the calculation to determine the borrowing capacity of the revolving credit facility.

+ References

No definition available.

+ Details

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

- Definition

The maximum amount of eligible inventory that can be attributed to the calculation to determine the borrowing capacity of the revolving credit facility.

+ References

No definition available.

+ Details

Name:	wlk_LineOfCreditFacilityLimitedToInventory
Namespace Prefix:	wlk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents a percentage, that when multiplied by the appraised net orderly liquidation value of eligible inventory, becomes a factor used in the calculation to determine the borrowing capacity of the revolving credit facility.

+ References

No definition available.

+ Details

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

- Definition

Represents a percentage, that when multiplied by the value of the lower of cost or market of eligible inventory, becomes a factor used in the calculation to determine the borrowing capacity of the revolving credit facility.

+ References

No definition available.

+ Details

Name:	wlk_LineOfCreditFacilityLimitedToLesserOfEligibleInventoryPercentage
Namespace Prefix:	wlk_
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:	debit
Period Type:	duration

- Definition

The minimum allowable borrowing availability under the line of credit facility without potentially triggering additional compliance requirements for the credit facility.

+ References

No definition available.

+ Details

Name:	wlk_MinimumBorrowingAvailability
Namespace Prefix:	wlk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant