XML 12 R1.htm IDEA: XBRL DOCUMENT v3.25.3
Cover - shares
 9 Months Ended
Sep. 28, 2025
Oct. 31, 2025
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Sep. 28, 2025  
Document Transition Report false  
Entity File Number 001-40866  
Entity Registrant Name First Watch Restaurant Group, Inc.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 82-4271369  
Entity Address, Address Line One 8725 Pendery Place  
Entity Address, Address Line Two Suite 201  
Entity Address, City or Town Bradenton  
Entity Address, State or Province FL  
Entity Address, Postal Zip Code 34201  
City Area Code 941  
Local Phone Number 907-9800  
Title of 12(b) Security Common Stock, $0.01 par value  
Trading Symbol FWRG  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company true  
Entity Ex Transition Period true  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   61,032,105
Entity Central Index Key 0001789940  
Amendment Flag false  
Current Fiscal Year End Date --12-28  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q3