Note 3 - Investment Securities - Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Securities available for sale, amortized cost, due in one year or less	$ 2,043
Securities available for sale, fair value, due in one year or less	2,049
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	182,653
Securities available for sale, fair value, due after one year through five years	181,145
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	56,104
Securities available for sale, fair value, due after five years through ten years	57,063
Securities held to maturity, amortized cost, due after five years through ten years	0
Securities held to maturity, fair value, due after five years through ten years	0
Securities available for sale, amortized cost, due after ten years	93,790
Securities available for sale, fair value, due after ten years	96,381
Securities held to maturity, amortized cost, due after ten years	2,000
Securities held to maturity, fair value, due after ten years	2,004
Securities available for sale, amortized cost, single maturity	334,590
Securities available for sale, fair value, single maturity	336,638
Securities held to maturity, amortized cost, single maturity	2,000
Securities held to maturity, fair value, single maturity	2,004
Mortgage-backed securities and CMO, amortized cost	110,630
Mortgage-backed securities and CMO, fair value	110,697
Mortgage-backed securities and CMO, amortized cost	0
Mortgage-backed securities and CMO, fair value	0
Securities available for sale, amortized cost	445,220	$ 274,709
Securities available for sale, fair value	447,335	283,502
Securities held to maturity, amortized cost	2,000	$ 0
Securities held to maturity, fair value	$ 2,004