v3.26.1
Summary of significant accounting policies - Nature of operations and Basis of presentation (Details)
3 Months Ended
Apr. 24, 2026
$ / shares
Mar. 31, 2026
Office
$ / shares
Mar. 31, 2025
$ / shares
Summary of significant accounting policies      
Number of full-service community banking offices | Office   40  
Cash dividends declared (in dollars per share)   $ 0.625 $ 0.6175
2026 Q2 dividend | Subsequent events      
Summary of significant accounting policies      
Dividend declared date Apr. 24, 2026    
Cash dividends declared (in dollars per share) $ 0.625    
Dividend payable date Jun. 15, 2026    
Dividend record date May 29, 2026