| Document And Entity Information | Nov. 16, 2021 |
| Document Information [Line Items] | |
| Entity, Registrant Name | TIDEWATER INC. |
| Document, Type | 8-K |
| Document, Period End Date | Nov. 16, 2021 |
| Entity, Incorporation, State or Country Code | DE |
| Entity, File Number | 1-6311 |
| Entity, Tax Identification Number | 72-0487776 |
| Entity, Address, Address Line One | 6002 Rogerdale Road, Suite 600 |
| Entity, Address, City or Town | Houston |
| Entity, Address, State or Province | TX |
| Entity, Address, Postal Zip Code | 77072 |
| City Area Code | 713 |
| Local Phone Number | 470-5300 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity, Emerging Growth Company | false |
| Amendment Flag | false |
| Entity, Central Index Key | 0000098222 |
| CommonStock Custom [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Common stock |
| Trading Symbol | TDW |
| Security Exchange Name | NYSE |
| SeriesAWarrantsToPurchaseSharesOfCommonStock Custom [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Series A Warrants to purchase shares of common stock |
| Trading Symbol | TDW.WS.A |
| Security Exchange Name | NYSE |
| SeriesBWarrantsToPurchaseSharesOfCommonStock Custom [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Series B Warrants to purchase shares of common stock |
| Trading Symbol | TDW.WS.B |
| Security Exchange Name | NYSE |
| WarrantsToPurchaseSharesOfCommonStock Custom [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Warrants to purchase shares of common stock |
| Trading Symbol | TDW.WS |
| Security Exchange Name | NYSEAMER |
| PreferredStockPurchaseRights Custom [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Preferred stock purchase rights |
| Trading Symbol | N/A |
| Security Exchange Name | NYSE |
