v3.26.1
Cover - shares
 3 Months Ended
Mar. 31, 2026
May 11, 2026
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2026  
Document Transition Report false  
Entity File Number 001-42844  
Registrant Name Black Rock Coffee Bar, Inc.  
Entity Incorporation, State or Country Code TX  
Entity Tax Identification Number 33-5053729  
Entity Address, Address Line One 9170 E. Bahia Drive  
Entity Address, Address Line Two Suite 101  
Entity Address, City or Town Scottsdale  
Entity Address, State or Province AZ  
Entity Address, Postal Zip Code 85260  
City Area Code 458  
Local Phone Number 256-9668  
Title of 12(b) Security Class A common stock, par value $0.00001 per share  
Trading Symbol BRCB  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company false  
Entity Central Index Key 0002068577  
Amendment Flag false  
Document Fiscal Period Focus Q1  
Document Fiscal Year Focus 2026  
Current Fiscal Year End Date --12-31  
Class A Common stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   21,572,893
Class B Common stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   10,377,136
Class C Common stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   18,105,778