Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

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- Definition

Amount of operating lease expense. Excludes sublease income.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918638-209977

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- 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.

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- Definition

Site lease agreement, number

+ References

No definition available.

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- Definition

Site lease expense

+ References

No definition available.

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Related Party Transactions Related Party Transactions (Related Party Leases) (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Aug. 04, 2014
Westlake Chemical OpCo LP [Member] \| Westlake [Member] \| Investee [Member] \| Site Lease Agreement [Member]
Related Party Transaction [Line Items]
Site lease agreement, number	2
Term of operating lease				50 years
Site lease expense	$ 1
Westlake [Member] \| Affiliated Entity [Member]
Related Party Transaction [Line Items]
Operating Lease, Expense	$ 2,343,000	$ 2,219,000	$ 2,284,000