Consolidated Balance Sheets (Parenthetical) - Common units [Member] - shares	Dec. 31, 2020	Dec. 31, 2019
Westlake [Member]
Limited Partners' Capital Account, Units Issued	14,122,230	14,122,230
Public [Member]
Limited Partners' Capital Account, Units Issued	21,076,673	21,072,315

The number of limited partner units issued.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 4.F)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187171-122770

Name:	us-gaap_LimitedPartnersCapitalAccountUnitsIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant