v3.25.2
Cover - $ / shares
 6 Months Ended
Jun. 30, 2025
Sep. 10, 2025
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Quarterly Report true  
Document Transition Report false  
Document Period End Date Jun. 30, 2025  
Document Fiscal Period Focus Q2  
Document Fiscal Year Focus 2025  
Current Fiscal Year End Date --12-31  
Entity File Number 0-15950  
Entity Registrant Name TRI-COUNTY FINANCIAL GROUP, INC.  
Entity Central Index Key 0001725262  
Entity Tax Identification Number 36-3412522  
Entity Incorporation, State or Country Code DE  
Entity Address, Address Line One 706 Washington Street  
Entity Address, City or Town Mendota  
Entity Address, State or Province IL  
Entity Address, Postal Zip Code 61342  
City Area Code (815)  
Local Phone Number 538-2265  
Title of 12(b) Security Common Stock, $1.00 par value  
Trading Symbol TYFG  
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  
Elected Not To Use the Extended Transition Period false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   2,377,518
Entity Listing, Par Value Per Share $ 1.00