Note 3 - Investment Securities - Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Securities available for sale, amortized cost, due in one year or less	$ 67,535
Securities available for sale, fair value, due in one year or less	65,951
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	149,731
Securities available for sale, fair value, due after one year through five years	140,052
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 year	41,277
Securities available for sale, fair value, due after five years through ten years	38,658
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	1,270
Securities available for sale, amortized cost, due after ten years	76,695
Securities available for sale, fair value, due after ten years	67,296
Securities held to maturity, amortized cost, due after ten years	5,000
Securities held to maturity, fair value, due after ten years	3,135
Securities available for sale, amortized cost, single maturity	335,238
Securities available for sale, fair value, single maturity	311,957
Securities held to maturity, amortized cost, single maturity	7,000
Securities held to maturity, fair value, single maturity	4,405
Mortgage-backed securities and CMO, amortized cost	126,257
Mortgage-backed securities and CMO, fair value	116,187
Mortgage-backed securities and CMO, amortized cost	0
Mortgage-backed securities and CMO, fair value	0
Securities available for sale, amortized cost	461,495	$ 468,549
Securities available for sale, fair value	428,144	437,271
Securities held to maturity, amortized cost	7,000	7,000
Securities held to maturity, fair value	$ 4,405	$ 4,446