v3.25.4
Cover - USD ($)
$ in Thousands
 12 Months Ended
Nov. 30, 2025
Mar. 06, 2026
May 31, 2025
Document Type 10-K    
Amendment Flag false    
Document Annual Report true    
Document Transition Report false    
Document Period End Date Nov. 30, 2025    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2025    
Current Fiscal Year End Date --11-30    
Entity File Number 001-41667    
Entity Registrant Name Black Hawk Acquisition Corporation    
Entity Central Index Key 0002000775    
Entity Tax Identification Number 00-0000000    
Entity Incorporation, State or Country Code E9    
Entity Address, Address Line One 125 Blackhawk Plaza Circle    
Entity Address, Address Line Two Suite 166    
Entity Address, City or Town Danville    
Entity Address, State or Province CA    
Entity Address, Postal Zip Code 94506    
City Area Code (915)    
Local Phone Number 217-4482    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
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    
Elected Not To Use the Extended Transition Period false    
Entity Shell Company true    
Entity Public Float     $ 73,900
Entity Common Stock, Shares Outstanding   4,153,577  
ICFR Auditor Attestation Flag false    
Document Financial Statement Error Correction [Flag] false    
Rule 10b5-1 Arrangement Adopted [Flag] false    
Non-Rule 10b5-1 Arrangement Adopted [Flag] false    
Rule 10b5-1 Arrangement Terminated [Flag] false    
Non-Rule 10b5-1 Arrangement Terminated [Flag] false    
Auditor Firm ID 206    
Auditor Name MaloneBailey, LLP    
Auditor Location Houston, Texas    
Units Each Consisting Of One Ordinary Share 0. 0001 Par Value And Onefifth 15 Of One Right Entitling Holder Thereof To Receive One Class Ordinary Share Upon Consummation Of Our Initial Business Combination [Member]      
Title of 12(b) Security Units, each consisting of one ordinary share, $0.0001 par value    
Trading Symbol BKHAU    
Security Exchange Name NASDAQ    
Ordinary shares, par value $0.0001 per share      
Title of 12(b) Security Ordinary shares, par value $0.0001 per share    
Trading Symbol BKHA    
Security Exchange Name NASDAQ    
Rights Each Right Entitling Holder To Receive One Class Ordinary Share Upon Consummation Of Our Initial Business Combination [Member]      
Title of 12(b) Security Rights, each right entitling the holder to receive one Class A ordinary share upon the consummation of our initial business combination    
Trading Symbol BKHAR    
Security Exchange Name NASDAQ