v3.26.1
Cover - shares
 6 Months Ended
Jun. 30, 2026
Aug. 13, 2026
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Entity Interactive Data Current Yes  
Amendment Flag false  
Document Period End Date Jun. 30, 2026  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q2  
Entity Information [Line Items]    
Entity Registrant Name FIFTH ERA ACQUISITION CORP I  
Entity Central Index Key 0002025401  
Entity File Number 001-42539  
Entity Tax Identification Number 36-5108801  
Entity Incorporation, State or Country Code E9  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Shell Company true  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Contact Personnel [Line Items]    
Entity Address, Address Line One PO Box 1093 Boundary Hall  
Entity Address, Address Line Two Cricket Square  
Entity Address, City or Town Grand Cayman  
Entity Address, Country KY  
Entity Address, Postal Zip Code KY1-1102  
Entity Phone Fax Numbers [Line Items]    
City Area Code 310  
Local Phone Number 545-9265  
Units, each consisting of one Class A Ordinary Share and one Right    
Entity Listings [Line Items]    
Title of 12(b) Security Units, each consisting of one Class A Ordinary Share and one Right  
Trading Symbol FERAU  
Security Exchange Name NASDAQ  
Class A Ordinary Shares, par value $0.0001 per share    
Entity Listings [Line Items]    
Title of 12(b) Security Class A Ordinary Shares, par value $0.0001 per share  
Trading Symbol FERA  
Security Exchange Name NASDAQ  
Rights, each entitling the holder to receive one-tenth (1/10) of one Class A Ordinary Share upon the consummation of a Business Combination    
Entity Listings [Line Items]    
Title of 12(b) Security Rights, each entitling the holder to receive one-tenth (1/10) of one Class A Ordinary Share upon the consummation of a Business Combination  
Trading Symbol FERAR  
Security Exchange Name NASDAQ  
Class A Ordinary Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   23,600,000
Class B Ordinary Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   7,666,667