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)

v3.26.1
Note 12 - Fair Value Measurement - Financial Assets and Liabilities Carried at Fair Value on Recurring Basis or Nonrecurring Basis (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Cash and cash equivalents $ 100,561 $ 95,127 [1]
Held to maturity debt securities 647,270 660,076 [1]
Federal funds sold 18,678 6,052 [1]
Mortgage loans held for sale 12,893 11,744 [1]
Restricted equity securities 12,466 12,203 [1]
Federal funds purchased 1,546,987 1,471,628 [1]
US Treasury Securities [Member]    
Held to maturity debt securities 249,675 249,621
Reported Value Measurement [Member]    
Cash and cash equivalents 1,817,944 1,121,734
Securities purchased with agreement to resell 499,087 498,910
Held to maturity debt securities 397,595 410,455
Federal funds sold 18,678 6,052
Mortgage loans held for sale 12,893 11,744
Restricted equity securities 12,466 12,203
Loans, net 13,772,008 13,525,229
Deposits 14,486,364 14,219,034
Federal funds purchased 1,546,987 1,471,628
Other borrowings 34,750 34,750
Reported Value Measurement [Member] | US Treasury Securities [Member]    
Held to maturity debt securities 249,675 249,621
Estimate of Fair Value Measurement [Member]    
Cash and cash equivalents 1,817,944 1,121,734
Securities purchased with agreement to resell 499,087 498,910
Held to maturity debt securities 362,221 376,503
Federal funds sold 18,678 6,052
Mortgage loans held for sale 12,893 11,744
Restricted equity securities 12,466 12,203
Loans, net 13,570,508 13,267,169
Deposits 14,483,407 14,217,711
Federal funds purchased 1,546,987 1,471,628
Other borrowings 31,413 31,258
Estimate of Fair Value Measurement [Member] | US Treasury Securities [Member]    
Held to maturity debt securities 240,255 240,032
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]    
Cash and cash equivalents 1,817,944 1,121,734
Securities purchased with agreement to resell 499,087 498,910
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 240,255 240,032
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]    
Cash and cash equivalents 0 0
Securities purchased with agreement to resell 0 0
Held to maturity debt securities 361,721 376,003
Federal funds sold 18,678 6,052
Mortgage loans held for sale 12,893 11,744
Restricted equity securities 12,466 12,203
Loans, net 0 0
Deposits 14,483,407 14,217,711
Federal funds purchased 1,546,987 1,471,628
Other borrowings 31,413 31,258
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]    
Cash and cash equivalents 0 0
Securities purchased with agreement to resell 0 0
Held to maturity debt securities 500 500
Federal funds sold 0 0
Mortgage loans held for sale 0 0
Restricted equity securities 0 0
Loans, net 13,570,508 13,267,169
Deposits 0 0
Federal funds purchased 0 0
Other borrowings $ 0 $ 0
[1] Derived from audited financial statements.