| Document and Entity Information | Dec. 30, 2021 |
| Document And Entity Information [Line Items] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001849489 |
| Document Type | 8-K |
| Document Period End Date | Dec. 30, 2021 |
| Entity Registrant Name | Arena Fortify Acquisition Corp. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-41046 |
| Entity Tax Identification Number | 86-2228751 |
| Entity Address, Address Line One | 405 Lexington Avenue |
| Entity Address, Address Line Two | 59th Floor |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10174 |
| City Area Code | 212 |
| Local Phone Number | 612-3205 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Units Each Consisting Of One Share Of Class A Common Stock 0.0001 Parvalue Per Share And One Half Of Oneredeemable Warrant [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Units, each consisting of one share ofClass A common stock, $0.0001 parvalue per share, and one-half of oneredeemable warrant |
| Trading Symbol | AFACU |
| Security Exchange Name | NASDAQ |
| Shares 160of 160 Class 160 A 160common 160stockbrincluded 160as 160part 160of 160the 160units [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Shares of Class A common stockincluded as part of the units |
| Trading Symbol | AFAC |
| Security Exchange Name | NASDAQ |
| Redeemable Warrants Included As Partof The Units Each Whole Warrantexercisable For One Share Of Class Acommon Stock At An Exercise Price Of 11.50 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Redeemable warrants included as partof the units, each whole warrantexercisable for one share of Class Acommon stock at an exercise price of$11.50 |
| Trading Symbol | AFACW |
| Security Exchange Name | NASDAQ |
| Shares Of Class A Common Stockunderlying Redeemable Warrantsincluded As Part Of The Units [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Shares of Class A common stockunderlying redeemable warrantsincluded as part of the units |
| Trading Symbol | AFAC |
| Security Exchange Name | NASDAQ |
