Quarterly report [Sections 13 or 15(d)]

Note 4 - Securities - Amortized Cost and Fair Value of Available-for-sale and Held-to-maturity Securities (Details)

v3.26.3
Note 4 - Securities - Amortized Cost and Fair Value of Available-for-sale and Held-to-maturity Securities (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Available for sale, amortized cost $ 985,042 $ 1,073,313
Available for sale, gross unrealized gain 1,196 6,128
Available for sale, gross unrealized loss (17,735) (10,616)
Available for sale, fair value 968,503 1,068,825
Held to maturity, amortized cost 594,596 660,076
Held to maturity, gross unrealized gain 0 743
Held to maturity, gross unrealized loss (61,491) (44,284)
Held to maturity debt securities, fair value 533,105 616,535
US Treasury Securities [Member]    
Available for sale, amortized cost 440,569 520,100
Available for sale, gross unrealized gain 0 2,823
Available for sale, gross unrealized loss (2,183) 0
Available for sale, fair value 438,386 522,923
Held to maturity, amortized cost 224,785 249,621
Held to maturity, gross unrealized gain 0 0
Held to maturity, gross unrealized loss (9,348) (9,589)
Held to maturity debt securities, fair value 215,437 240,032
Collateralized Mortgage-Backed Securities [Member]    
Available for sale, amortized cost 154,363 133,126
Available for sale, gross unrealized gain 0 1,030
Available for sale, gross unrealized loss (6,874) (852)
Available for sale, fair value 147,489 133,304
Held to maturity, amortized cost 363,792 402,097
Held to maturity, gross unrealized gain 0 743
Held to maturity, gross unrealized loss (51,792) (34,395)
Held to maturity debt securities, fair value 312,000 368,445
US States and Political Subdivisions Debt Securities [Member]    
Available for sale, amortized cost 9,855 10,362
Available for sale, gross unrealized gain 1 1
Available for sale, gross unrealized loss (625) (554)
Available for sale, fair value 9,231 9,809
Held to maturity, amortized cost 6,019 8,358
Held to maturity, gross unrealized gain 0 0
Held to maturity, gross unrealized loss (351) (300)
Held to maturity debt securities, fair value 5,668 8,058
Corporate Debt Securities [Member]    
Available for sale, amortized cost 380,255 409,725
Available for sale, gross unrealized gain 1,195 2,274
Available for sale, gross unrealized loss (8,053) (9,210)
Available for sale, fair value $ 373,397 $ 402,789