Note 3 - Investment Securities - Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Securities available for sale, amortized cost, due in one year or less	$ 61,941
Securities available for sale, fair value, due in one year or less	60,796
Securities held to maturity, amortized cost, due in one year or less	0
Securities held to maturity, fair value, due in one year or less	0
Securities available for sale, amortized cost, due after one year through five years	166,347
Securities available for sale, fair value, due after one year through five years	156,117
Securities held to maturity, amortized cost, due after one year through five years	0
Securities held to maturity, fair value, due after one year through five years	0
Securities available for sale, amortized cost, due after five years through ten years	42,731
Securities available for sale, fair value, due after five years through ten years	40,603
Securities held to maturity, amortized cost, due after five years through ten years	2,000
Securities held to maturity, fair value, due after five years through ten years	1,279
Securities available for sale, amortized cost, due after ten years	90,962
Securities available for sale, fair value, due after ten years	82,538
Securities held to maturity, amortized cost, due after ten years	5,000
Securities held to maturity, fair value, due after ten years	3,167
Securities available for sale, amortized cost, single maturity	361,981
Securities available for sale, fair value, single maturity	340,054
Securities held to maturity, amortized cost, single maturity	7,000
Securities held to maturity, fair value, single maturity	4,446
Mortgage-backed securities and CMO, amortized cost	106,568
Mortgage-backed securities and CMO, fair value	97,217
Mortgage-backed securities and CMO, amortized cost	0
Mortgage-backed securities and CMO, fair value	0
Securities available for sale, amortized cost	468,549	$ 507,466
Securities available for sale, fair value	437,271	460,819
Securities held to maturity, amortized cost	7,000	7,000
Securities held to maturity, fair value	$ 4,446	$ 5,311