| Document and Entity Information | Nov. 22, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001486159 |
| Document Type | 8-K |
| Document Period End Date | Nov. 22, 2021 |
| Entity Registrant Name | OASIS PETROLEUM INC. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-34776 |
| Entity Tax Identification Number | 80-0554627 |
| Entity Address, Address Line One | 1001 Fannin Street |
| Entity Address, Address Line Two | Suite 1500 |
| Entity Address, City or Town | Houston |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77002 |
| City Area Code | (281) |
| Local Phone Number | 404-9500 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock |
| Trading Symbol | OAS |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
