v3.25.4
Document and Entity Information - USD ($)
 10 Months Ended
Dec. 31, 2025
Mar. 06, 2026
Jun. 30, 2025
Document and Entity Information      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2025    
Document Transition Report false    
Entity File Number 001-42822    
Entity Registrant Name SPRING VALLEY ACQUISITION CORP. III    
Entity Incorporation, State or Country Code E9    
Entity Tax Identification Number 00-0000000    
Entity Address, Address Line One 2100 McKinney Ave.,    
Entity Address, Adress Line Two Suite 1675    
Entity Address, City or Town Dallas    
Entity Address State Or Province TX    
Entity Address, Postal Zip Code 10580    
City Area Code 214    
Local Phone Number 308-5230    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Inception Date Mar. 12, 2025    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company true    
Entity Ex Transition Period false    
ICFR Auditor Attestation Flag false    
Document Financial Statement Error Correction [Flag] false    
Entity Shell Company true    
Entity Public Float     $ 0
Entity Central Index Key 0002074850    
Current Fiscal Year End Date --12-31    
Document Fiscal Year Focus 2025    
Document Fiscal Period Focus FY    
Amendment Flag false    
Auditor Name WithumSmith+Brown, PC    
Auditor Location New York, New York    
Auditor Firm ID 100    
Units, each consisting of one Class A ordinary share and one-third of one redeemable warrant      
Document and Entity Information      
Title of 12(b) Security Units, each consisting of one Class A ordinary share and one-third of one redeemable warrant    
Trading Symbol SVACU    
Security Exchange Name NASDAQ    
Class A ordinary shares      
Document and Entity Information      
Title of 12(b) Security Class A ordinary shares, par value $0.0001 per share    
Trading Symbol SVAC    
Security Exchange Name NASDAQ    
Entity Common Stock, Shares Outstanding   23,000,000  
Warrants, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50      
Document and Entity Information      
Title of 12(b) Security Warrants, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50    
Trading Symbol SVACW    
Security Exchange Name NASDAQ    
Class B ordinary shares      
Document and Entity Information      
Entity Common Stock, Shares Outstanding   7,666,667