v3.25.2
Short and Long-Term Borrowings - Schedule of Junior Subordinated Debentures and Subordinated Notes (Details) - USD ($)
 6 Months Ended
Jun. 30, 2025
Dec. 31, 2024
Dec. 31, 2021
Jul. 31, 2021
Debt Instrument [Line Items]        
Carrying Value $ 134,340,000 $ 161,387,000    
Junior subordinated debentures        
Debt Instrument [Line Items]        
Par 48,045,000      
Unamortized Premium /(Discount) / Debt Issue Costs (6,246,000)      
Carrying Value $ 41,799,000 $ 41,384,000    
Adjustment on variable rate 0.26161%      
Junior subordinated debentures | 2005 Mid-Wisconsin Financial Services, Inc.        
Debt Instrument [Line Items]        
Interest Rate 6.01% 6.05%    
Par $ 10,310,000      
Unamortized Premium /(Discount) / Debt Issue Costs (2,076,000)      
Carrying Value $ 8,234,000 $ 8,134,000    
Floating interest rate basis spread 1.43%      
Junior subordinated debentures | 2006 Baylake Corp.        
Debt Instrument [Line Items]        
Interest Rate 5.91% 5.94%    
Par $ 16,598,000      
Unamortized Premium /(Discount) / Debt Issue Costs (2,583,000)      
Carrying Value $ 14,015,000 $ 13,897,000    
Floating interest rate basis spread 1.35%      
Junior subordinated debentures | 2004 First Menasha Bancshares, Inc.        
Debt Instrument [Line Items]        
Interest Rate 7.36% 7.40%    
Par $ 5,155,000      
Unamortized Premium /(Discount) / Debt Issue Costs (379,000)      
Carrying Value $ 4,776,000 $ 4,755,000    
Floating interest rate basis spread 2.79%      
Junior subordinated debentures | County Bancorp Statutory Trust II        
Debt Instrument [Line Items]        
Interest Rate 6.11% 6.15%    
Par $ 6,186,000      
Unamortized Premium /(Discount) / Debt Issue Costs (522,000)      
Carrying Value $ 5,664,000 $ 5,586,000    
Floating interest rate basis spread 1.53%      
Junior subordinated debentures | County Bancorp Statutory Trust III        
Debt Instrument [Line Items]        
Interest Rate 6.27% 6.31%    
Par $ 6,186,000      
Unamortized Premium /(Discount) / Debt Issue Costs (581,000)      
Carrying Value $ 5,605,000 $ 5,528,000    
Floating interest rate basis spread 1.69%      
Junior subordinated debentures | Fox River Valley Capital Trust        
Debt Instrument [Line Items]        
Interest Rate 7.89% 7.89%    
Par $ 3,610,000      
Unamortized Premium /(Discount) / Debt Issue Costs (105,000)      
Carrying Value $ 3,505,000 $ 3,484,000    
Floating interest rate basis spread 3.40%      
Subordinated notes        
Debt Instrument [Line Items]        
Par $ 92,750,000      
Unamortized Premium /(Discount) / Debt Issue Costs (209,000)      
Carrying Value $ 92,541,000 $ 115,003,000    
Subordinated notes | Subordinated Notes due 2031        
Debt Instrument [Line Items]        
Interest Rate 3.13% 3.13%    
Par $ 92,750,000     $ 100,000,000
Unamortized Premium /(Discount) / Debt Issue Costs (209,000)      
Carrying Value $ 92,541,000 $ 92,436,000    
Subordinated notes | County Subordinated Notes due 2030        
Debt Instrument [Line Items]        
Interest Rate 7.00% 7.00%    
Par $ 0   $ 22,000,000  
Unamortized Premium /(Discount) / Debt Issue Costs 0      
Carrying Value $ 0 $ 22,567,000