| Document and Entity Information | Mar. 14, 2022 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001788717 |
| Document Type | 8-K |
| Document Period End Date | Mar. 14, 2022 |
| Entity Registrant Name | F45 Training Holdings Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-40590 |
| Entity Tax Identification Number | 38-3978689 |
| Entity Address, Address Line One | 3601 South Congress Avenue |
| Entity Address, Address Line Two | Building E |
| Entity Address, City or Town | Austin |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 78704 |
| City Area Code | (737) |
| Local Phone Number | 787-1955 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common stock, par value $0.00005 per share |
| Trading Symbol | FXLV |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
