v3.26.1
Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)
 3 Months Ended
Mar. 31, 2025
Mar. 01, 2025
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Apr. 30, 2021
Significant Accounting Policies [Line Items]            
Stock repurchase program, number of shares authorized to be repurchased (in shares)           375,388
Stock repurchase program, percent of stock outstanding           5.00%
Securities held to maturity, Accrued interest receivable     $ 2,300,000   $ 2,000,000  
Shares issued for directors and employee stock plans     $ 255,000 $ 172,000    
Shares repurchased     50,000      
Shares repurchased, cost     $ 1,441,000      
Shares remaining to purchase under repurchase plan     300,272      
Number of days individually evaluation     60 days      
Fentura Financial, Inc. [Member]            
Significant Accounting Policies [Line Items]            
Shares issued for directors and employee stock plans (in shares)   6,070,836        
Cash price $ 1,800,000          
Common stock purchased   $ 57,807        
Shares issued for directors and employee stock plans   $ 193,000,000        
Directors' Stock Purchase Plan [Member]            
Significant Accounting Policies [Line Items]            
Shares issued for directors and employee stock plans (in shares)     5,978 3,301    
Shares issued for directors and employee stock plans     $ 177,000 $ 118,000    
Employee Stock Purchase Plan [Member]            
Significant Accounting Policies [Line Items]            
Shares issued for directors and employee stock plans (in shares)     3,283 2,214    
Shares issued for directors and employee stock plans     $ 91,000 $ 67,000    
FETM Shares Retired [Member]            
Significant Accounting Policies [Line Items]            
Shares issued for directors and employee stock plans (in shares)   6,750        
Shares issued for directors and employee stock plans $ 215,000