v3.26.1
Mortgage Banking Activities, Mortgage Servicing Rights (Details)
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Summary of Mortgage Servicing Rights [Abstract]          
Number of residential mortgage loans serviced for others 121,859   121,859   123,263
Outstanding principal balance of residential mortgage loans serviced for others $ 21,592,573,000   $ 21,592,573,000   $ 21,760,414,000
Weighted average interest rate 3.87%   3.87%   3.83%
Remaining term (in months)     268 months   270 months
Servicing Asset at Fair Value, Amount [Roll Forward]          
Beginning balance $ 333,381,000 $ 342,111,000 $ 322,724,000 $ 338,145,000 $ 338,145,000
Additions 4,830,000 3,063,000 8,840,000 5,572,000  
Acquisitions 0 0 8,645,000 14,615,000  
Changes due to principal payments (10,513,000) (5,511,000) (20,666,000) (11,429,000)  
Change in fair value due to market assumption changes 6,300,000 (5,019,000) 14,455,000 (12,259,000)  
Ending balance $ 333,998,000 $ 334,644,000 $ 333,998,000 $ 334,644,000 $ 322,724,000
Servicing Assets at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]          
Discount rate - risk-free rate plus a market premium (in hundredths)     9.61%   9.31%
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Prepayment Speed     6.80%   7.07%
Loan servicing costs - annually per loan based upon loan type, performing, minimum (in dollars per loan)     $ 73   $ 73
Loan servicing costs - annually per loan based upon loan type, performing, maximum (in dollars per loan)     94   94
Loan servicing costs - annually per loan based upon loan type, delinquent, minimum (in dollars per loan)     150   150
Loan servicing costs - annually per loan based upon loan type, delinquent, maximum (in dollars per loan)     500   500
Loan servicing costs - annually per loan based upon loan type, foreclosure, minimum (in dollars per loan)     875   875
Loan servicing costs - annually per loan based upon loan type, foreclosure, maximum (in dollars per loan)     $ 6,000   $ 6,000
Escrow earnings rate - indexed to rates paid on deposit accounts with comparable average life (in hundredths)     4.09%   3.66%
Primary secondary mortgage rate spread 125   125   128
Delinquency rate     2.33%   2.28%