Note 3 - Investment Securities - Portfolio of Securities Available-for-sale (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Amortized cost	$ 709,388	$ 721,799
Gross unrealized gains	578	289
Gross unrealized losses	(80,965)	(87,204)
Securities available-for-sale	629,001	634,884
Allowance for investment credit losses	0	0
US Government Agencies Debt Securities [Member]
Amortized cost	53,301	54,889
Gross unrealized gains	1	0
Gross unrealized losses	(9,787)	(10,439)
Securities available-for-sale	43,515	44,450
Allowance for investment credit losses	0	0
Residential Mortgage-Backed Securities [Member]
Amortized cost	469,925	475,263
Gross unrealized gains	322	178
Gross unrealized losses	(50,580)	(57,863)
Securities available-for-sale	419,667	417,578
Allowance for investment credit losses	0	0
Commercial Mortgage-Backed Securities [Member]
Amortized cost	25,424	25,485
Gross unrealized gains	0	0
Gross unrealized losses	(3,464)	(4,381)
Securities available-for-sale	21,960	21,104
Allowance for investment credit losses	0	0
US States and Political Subdivisions Debt Securities [Member]
Amortized cost	155,101	157,247
Gross unrealized gains	255	111
Gross unrealized losses	(17,060)	(14,462)
Securities available-for-sale	138,296	142,896
Allowance for investment credit losses	0	0
Corporate Debt Securities [Member]
Amortized cost	4,000	7,000
Gross unrealized gains	0	0
Gross unrealized losses	(23)	(26)
Securities available-for-sale	3,977	6,974
Allowance for investment credit losses	0	0
Asset-Backed Securities [Member]
Amortized cost	1,505	1,673
Gross unrealized gains	0	0
Gross unrealized losses	(51)	(33)
Securities available-for-sale	1,454	1,640
Allowance for investment credit losses	0	0
Other Debt Obligations [Member]
Amortized cost	132	242
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Securities available-for-sale	132	242
Allowance for investment credit losses	$ 0	$ 0