Note 2 - Investment Securities - Summary of Continuous Unrealized Loss Position for Securities Classified as AFS (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Obligations of the U.S. Treasury and U.S. government agencies and corporations	$ 5,526	$ 210,918
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(491)	(24,039)
Obligations of the U.S. Treasury and U.S. government agencies and corporations	329,283	164,186
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(57,207)	(38,440)
Obligations of the U.S. Treasury and U.S. government agencies and corporations	334,809	375,104
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(57,698)	(62,479)
US Government Corporations and Agencies Securities [Member]
Obligations of the U.S. Treasury and U.S. government agencies and corporations	1,268	16,017
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(7)	(688)
Obligations of the U.S. Treasury and U.S. government agencies and corporations	9,284	1,013
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(433)	(11)
Obligations of the U.S. Treasury and U.S. government agencies and corporations	10,552	17,030
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(440)	(699)
US States and Political Subdivisions Debt Securities [Member]
Obligations of the U.S. Treasury and U.S. government agencies and corporations	0	13,695
Obligations of the U.S. Treasury and U.S. government agencies and corporations	0	(1,427)
Obligations of the U.S. Treasury and U.S. government agencies and corporations	15,425	4,524
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(2,076)	(1,300)
Obligations of the U.S. Treasury and U.S. government agencies and corporations	15,425	18,219
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(2,076)	(2,727)
Corporate Debt Securities [Member]
Obligations of the U.S. Treasury and U.S. government agencies and corporations	468	19,606
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(28)	(1,170)
Obligations of the U.S. Treasury and U.S. government agencies and corporations	25,888	10,085
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(3,713)	(2,365)
Obligations of the U.S. Treasury and U.S. government agencies and corporations	26,356	29,691
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(3,741)	(3,535)
Residential Mortgage-Backed Securities [Member]
Obligations of the U.S. Treasury and U.S. government agencies and corporations	2,705	134,419
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(421)	(18,122)
Obligations of the U.S. Treasury and U.S. government agencies and corporations	228,415	116,132
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(42,498)	(28,904)
Obligations of the U.S. Treasury and U.S. government agencies and corporations	231,120	250,551
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(42,919)	(47,026)
Commercial Mortgage-Backed Securities [Member]
Obligations of the U.S. Treasury and U.S. government agencies and corporations	1,085	27,181
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(35)	(2,632)
Obligations of the U.S. Treasury and U.S. government agencies and corporations	50,271	32,432
Obligations of the U.S. Treasury and U.S. government agencies and corporations	(8,487)	(5,860)
Obligations of the U.S. Treasury and U.S. government agencies and corporations	51,356	59,613
Obligations of the U.S. Treasury and U.S. government agencies and corporations	$ (8,522)	$ (8,492)