| Cover | Mar. 04, 2021 |
| Schedule of Capitalization, Equity [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 4, 2021 |
| Entity File Number | 001-38382 |
| Entity Registrant Name | FTS INTERNATIONAL, INC. |
| Entity Central Index Key | 0001529463 |
| Entity Tax Identification Number | 30-0780081 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 777 Main Street |
| Entity Address, Address Line Two | Suite 2900 |
| Entity Address, City or Town | Fort Worth |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 76102 |
| City Area Code | 817 |
| Local Phone Number | 862-2000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Class A Common Stock, par value $0.01 per share | |
| Schedule of Capitalization, Equity [Line Items] | |
| Title of 12(b) Security | Class A Common Stock, par value $0.01 per share |
| Trading Symbol | FTSI |
| Security Exchange Name | NYSEAMER |
| Series A Preferred Purchase Rights | |
| Schedule of Capitalization, Equity [Line Items] | |
| Title of 12(b) Security | Series A Preferred Purchase Rights |
| Security Exchange Name | NYSEAMER |
