v3.26.1
Computation of Earnings Per Common Share - Schedule of Earnings Per Share (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]        
Average number of common shares outstanding for basic calculation 7,330,929 7,383,338 7,324,794 7,400,370
Average number of common shares outstanding used to calculate diluted earnings per common share 7,337,378 7,398,109 7,332,078 7,413,974
Net income $ 5,041 $ 5,031 $ 10,033 $ 8,980
Basic (in dollars per share) $ 0.69 $ 0.68 $ 1.37 $ 1.21
Diluted (in dollars per share) $ 0.69 $ 0.68 $ 1.37 $ 1.21
Isabella Bank Corporation Restricted Stock Plan        
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]        
Dilutive effect of stock compensation, awards, and options 6,449 14,771 7,284 13,604