Note 2 - Investment Securities - Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Securities available for sale, amortized cost, due in one year or less	$ 201
Securities available for sale, fair value, due in one year or less	201
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	200,587
Securities available for sale, fair value, due after one year through five years	191,701
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	52,276
Securities available for sale, fair value, due after five years through ten years	50,378
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	1,894
Securities available for sale, amortized cost, due after ten years	97,118
Securities available for sale, fair value, due after ten years	90,196
Securities held to maturity, amortized cost, due after ten years	5,000
Securities held to maturity, fair value, due after ten years	4,739
Securities available for sale, amortized cost, single maturity	350,182
Securities available for sale, fair value, single maturity	332,476
Securities held to maturity, amortized cost, single maturity	7,000
Securities held to maturity, fair value, single maturity	6,633
Mortgage-backed securities and CMO, amortized cost	110,785
Mortgage-backed securities and CMO, fair value	105,692
Mortgage-backed securities and CMO, amortized cost	0
Mortgage-backed securities and CMO, fair value	0
Securities available for sale, amortized cost	460,967	$ 445,220
Securities available for sale, fair value	438,168	447,335
Securities held to maturity, amortized cost	7,000	2,000
Securities held to maturity, fair value	$ 6,633	$ 2,004