Guarantor Disclosures (Additional Information) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	0 Months Ended
Sep. 30, 2014 3.60% Senior Notes Due 2022	Aug. 04, 2014 Limited Partner [Member] IPO [Member]	Aug. 04, 2014 Limited Partner [Member] Westlake Chemical Partners LP [Member] Subsidiaries [Member] IPO [Member]
Condensed Financial Statements, Captions [Line Items]
Stated interest rate	3.60%
Maturity	2022
Minimum debt amount guaranteed by subsidiaries	$ 5,000
Limited partner interest		89.40%	10.60%

Contractual interest rate for funds borrowed, under the debt agreement.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 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 210.5-02.22(a)(1))

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

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