Quarterly report [Sections 13 or 15(d)]

Note 12 - Fair Value Measurement - Financial Assets and Liabilities Carried at Fair Value on Recurring Basis or Nonrecurring Basis (Details)

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Note 12 - Fair Value Measurement - Financial Assets and Liabilities Carried at Fair Value on Recurring Basis or Nonrecurring Basis (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Cash and due from banks $ 115,442 $ 95,127
Interest-bearing balances due from depository institutions 11,553,328 11,534,762
Federal funds sold 1,000 6,052
Held to maturity debt securities 635,480 660,076
Mortgage loans held for sale 14,886 11,744
Restricted equity securities 12,475 12,203
Federal funds purchased 1,579,388 1,471,628
US Treasury Securities [Member]    
Held to maturity debt securities 249,730 249,621
Reported Value Measurement [Member]    
Cash and due from banks 115,442 95,127
Interest-bearing balances due from depository institutions 1,089,592 1,026,607
Securities purchased with agreement to resell 250,439 498,910
Federal funds sold 1,000 6,052
Held to maturity debt securities 385,750 410,455
Mortgage loans held for sale 14,886 11,744
Restricted equity securities 12,475 12,203
Loans, net 14,296,636 13,525,229
Deposits 14,548,730 14,219,034
Federal funds purchased 1,579,388 1,471,628
Other borrowings 34,750 34,750
Reported Value Measurement [Member] | US Treasury Securities [Member]    
Held to maturity debt securities 249,730 249,621
Estimate of Fair Value Measurement [Member]    
Cash and due from banks 115,442 95,127
Interest-bearing balances due from depository institutions 1,089,592 1,026,607
Securities purchased with agreement to resell 250,439 498,910
Federal funds sold 1,000 6,052
Held to maturity debt securities 349,570 376,503
Mortgage loans held for sale 14,886 11,744
Restricted equity securities 12,475 12,203
Loans, net 14,123,112 13,267,169
Deposits 14,544,901 14,217,711
Federal funds purchased 1,579,388 1,471,628
Other borrowings 31,571 31,258
Estimate of Fair Value Measurement [Member] | US Treasury Securities [Member]    
Held to maturity debt securities 240,710 240,032
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]    
Cash and due from banks 115,442 95,127
Interest-bearing balances due from depository institutions 1,089,592 1,026,607
Securities purchased with agreement to resell 250,439 498,910
Federal funds sold 0 0
Mortgage loans held for sale 0 0
Restricted equity securities 0 0
Loans, net 0 0
Deposits 0 0
Federal funds purchased 0 0
Other borrowings 0 0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]    
Held to maturity debt securities 240,710 240,032
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]    
Cash and due from banks 0 0
Interest-bearing balances due from depository institutions 0 0
Securities purchased with agreement to resell 0 0
Federal funds sold 1,000 6,052
Held to maturity debt securities 348,070 376,003
Mortgage loans held for sale 14,886 11,744
Restricted equity securities 12,475 12,203
Loans, net 0 0
Deposits 14,544,901 14,217,711
Federal funds purchased 1,579,388 1,471,628
Other borrowings 31,571 31,258
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]    
Cash and due from banks 0 0
Interest-bearing balances due from depository institutions 0 0
Securities purchased with agreement to resell 0 0
Federal funds sold 0 0
Held to maturity debt securities 1,500 500
Mortgage loans held for sale 0 0
Restricted equity securities 0 0
Loans, net 14,123,112 13,267,169
Deposits 0 0
Federal funds purchased 0 0
Other borrowings $ 0 $ 0