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)

v3.26.1
Note 4 - Securities - Amortized Cost and Fair Value of Available-for-sale and Held-to-maturity Securities (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Available for sale, amortized cost $ 1,042,706 $ 1,073,313
Available for sale, gross unrealized gain 4,706 6,128
Available for sale, gross unrealized loss (10,261) (10,616)
Available for sale, fair value 1,037,151 1,068,825 [1]
Held to maturity, amortized cost 647,270 660,076 [1]
Held to maturity, gross unrealized gain 474 743
Held to maturity, gross unrealized loss (45,268) (44,284)
Held to maturity debt securities, fair value 602,476 616,535
US Treasury Securities [Member]    
Available for sale, amortized cost 470,349 520,100
Available for sale, gross unrealized gain 1,344 2,823
Available for sale, gross unrealized loss 0 0
Available for sale, fair value 471,693 522,923
Held to maturity, amortized cost 249,675 249,621
Held to maturity, gross unrealized gain 0 0
Held to maturity, gross unrealized loss (9,420) (9,589)
Held to maturity debt securities, fair value 240,255 240,032
Collateralized Mortgage-Backed Securities [Member]    
Available for sale, amortized cost 123,874 133,126
Available for sale, gross unrealized gain 412 1,030
Available for sale, gross unrealized loss (1,126) (852)
Available for sale, fair value 123,160 133,304
Held to maturity, amortized cost 389,231 402,097
Held to maturity, gross unrealized gain 474 743
Held to maturity, gross unrealized loss (35,555) (34,395)
Held to maturity debt securities, fair value 354,150 368,445
US States and Political Subdivisions Debt Securities [Member]    
Available for sale, amortized cost 10,360 10,362
Available for sale, gross unrealized gain 1 1
Available for sale, gross unrealized loss (539) (554)
Available for sale, fair value 9,822 9,809
Held to maturity, amortized cost 8,364 8,358
Held to maturity, gross unrealized gain 0 0
Held to maturity, gross unrealized loss (293) (300)
Held to maturity debt securities, fair value 8,071 8,058
Corporate Debt Securities [Member]    
Available for sale, amortized cost 438,123 409,725
Available for sale, gross unrealized gain 2,949 2,274
Available for sale, gross unrealized loss (8,596) (9,210)
Available for sale, fair value $ 432,476 $ 402,789
[1] Derived from audited financial statements.