v3.26.1
Fair Value Measurements (Estimated Fair Values of Financial Instruments) (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Held to maturity securities $ 1,885,139 $ 2,132,882
Loans held for sale 42,867 33,158
Derivative financial instruments, Financial assets 45,403 46,120
Derivative financial instruments, Financial liabilities 27,078 36,259
Total Fair Value [Member]    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Cash, interest-bearing bank deposits, and federal funds sold 1,087,121 695,261
Available for sale securities 6,006,220 5,961,917
Held to maturity securities 1,755,583 2,011,026
Loans, net 24,118,056 23,588,681
Loans held for sale 52,850 33,158
Derivative financial instruments, Financial assets 49,137 63,126
Deposits 29,617,567 29,274,190
Federal funds purchased 325 70,400
Securities sold under agreements to repurchase 620,645 546,892
Short-term FHLB Borrowings 950,664 400,000
Long-term debt 154,915 162,257
Derivative financial instruments, Financial liabilities 91,681 95,367
Total Fair Value [Member] | Level 1 [Member]    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Cash, interest-bearing bank deposits, and federal funds sold 1,086,926 695,032
Total Fair Value [Member] | Level 2 [Member]    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Cash, interest-bearing bank deposits, and federal funds sold 195 229
Available for sale securities 6,006,220 5,961,917
Held to maturity securities 1,755,583 2,011,026
Loans held for sale 42,867 33,158
Derivative financial instruments, Financial assets 49,137 63,126
Federal funds purchased 325 70,400
Securities sold under agreements to repurchase 620,645 546,892
Short-term FHLB Borrowings 950,664 400,000
Long-term debt 154,915 162,257
Derivative financial instruments, Financial liabilities 90,695 94,083
Total Fair Value [Member] | Level 3 [Member]    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Loans, net 24,118,056 23,588,681
Loans held for sale 9,983  
Deposits 29,617,567 29,274,190
Derivative financial instruments, Financial liabilities 986 1,284
Carrying Amount [Member]    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Cash, interest-bearing bank deposits, and federal funds sold 1,087,121 695,261
Available for sale securities 6,006,220 5,961,917
Held to maturity securities 1,885,139 2,132,882
Loans, net 24,267,565 23,650,709
Loans held for sale 52,850 33,158
Derivative financial instruments, Financial assets 49,137 63,126
Deposits 29,629,760 29,279,774
Federal funds purchased 325 70,400
Securities sold under agreements to repurchase 620,645 546,892
Short-term FHLB Borrowings 950,000 400,000
Long-term debt 193,823 199,407
Derivative financial instruments, Financial liabilities $ 91,681 $ 95,367