v3.26.1
Note 25 - Subsequent Event (Details Textual)
$ in Thousands
May 01, 2026
USD ($)
Mar. 31, 2026
USD ($)
Dec. 31, 2025
USD ($)
Mar. 31, 2025
USD ($)
Assets   $ 9,466,856 $ 9,536,124 $ 8,997,478
Deposits   7,757,236 7,791,137  
Investment Management and Trust [Member]        
Assets   32,968   $ 33,713
Assets under Management, Carrying Amount   7,600,000 $ 7,640,000  
Field & Main Bancorp, Inc. [Member]        
Assets   860,000    
Financing Receivable, before Allowance for Credit Loss   640,000    
Deposits   780,000    
Field & Main Bancorp, Inc. [Member] | Investment Management and Trust [Member]        
Assets under Management, Carrying Amount   $ 791,000    
Subsequent Event [Member]        
Number of Branches 81      
Subsequent Event [Member] | Field & Main Bancorp, Inc. [Member]        
Number of Branches 6      
Subsequent Event [Member] | Field & Main Bancorp, Inc. [Member]        
Business Combination, Consideration Transferred $ 112,000      
Business Combination, Recognized Asset Acquired, Asset 10,300,000      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans, Gross 7,900,000      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits 8,500,000      
Business Combination, Recognized Asset Acquired, Assets Under Management $ 8,400,000