| Cover Page | Dec. 15, 2020 | Nov. 10, 2020 | Dec. 31, 2020 |
| Cover [Abstract] | |||
| Document Type | 8-K | ||
| Document Period End Date | Jan. 18, 2021 | ||
| Entity Registrant Name | OASIS PETROLEUM INC. | ||
| Entity Incorporation, State or 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 | ||
| Title of 12(b) Security | Common Stock | ||
| Trading Symbol | OAS | ||
| Security Exchange Name | NASDAQ | ||
| Entity Emerging Growth Company | false | ||
| Entity Central Index Key | 0001486159 | ||
| Amendment Flag | false | ||
| Current Fiscal Year End Date |
