| Cover Page | Nov. 02, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Nov. 2, 2021 |
| Entity Registrant Name | Westlake Chemical Partners LP |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-36567 |
| Entity Tax Identification Number | 32-0436529 |
| Entity Address, Address Line One | 2801 Post Oak Boulevard, |
| Entity Address, Address Line Two | Suite 600 |
| Entity Address, City or Town | Houston, |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77056 |
| City Area Code | 713 |
| Local Phone Number | 585-2900 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common units representing limited partnership interests |
| Trading Symbol | WLKP |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001604665 |
| Amendment Flag | false |
