Note 2 - Investment Securities - Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Securities available for sale, amortized cost, due in one year or less	$ 16,194
Securities available for sale, fair value, due in one year or less	15,800
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	237,878
Securities available for sale, fair value, due after one year through five years	220,169
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	43,996
Securities available for sale, fair value, due after five years through ten years	40,360
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	1,608
Securities available for sale, amortized cost, due after ten years	103,386
Securities available for sale, fair value, due after ten years	85,009
Securities held to maturity, amortized cost, due after ten years	5,000
Securities held to maturity, fair value, due after ten years	4,010
Securities available for sale, amortized cost, single maturity	401,454
Securities available for sale, fair value, single maturity	361,338
Securities held to maturity, amortized cost, single maturity	7,000
Securities held to maturity, fair value, single maturity	5,618
Mortgage-backed securities and CMO, amortized cost	106,493
Mortgage-backed securities and CMO, fair value	93,941
Mortgage-backed securities and CMO, amortized cost	0
Mortgage-backed securities and CMO, fair value	0
Securities available for sale, amortized cost	507,947	$ 445,220
Securities available for sale, fair value	455,279	447,335
Securities held to maturity, amortized cost	7,000	2,000
Securities held to maturity, fair value	$ 5,618	$ 2,004