Note 5 - Debt Securities - Summary of Amortized Cost and Fair Value of Available-for-sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt securities, available for sale, amortized cost	$ 541,196	$ 455,067
Available for sale securities, unrealized gains	1,534	721
Available for sale securities, unrealized losses	39,968	50,587
Debt securities available for sale (at fair value)	502,762	405,201
US Government Corporations and Agencies Securities [Member]
Debt securities, available for sale, amortized cost	23,295	20,446
Available for sale securities, unrealized gains	38	83
Available for sale securities, unrealized losses	508	310
Debt securities available for sale (at fair value)	22,825	20,219
Government Sponsored Agencies [Member]
Debt securities, available for sale, amortized cost	133,709	55,184
Available for sale securities, unrealized gains	729	80
Available for sale securities, unrealized losses	4,871	3,808
Debt securities available for sale (at fair value)	129,567	51,456
Nongovernment Sponsored Agencies [Member]
Debt securities, available for sale, amortized cost	78,350	65,860
Available for sale securities, unrealized gains	22	48
Available for sale securities, unrealized losses	4,503	4,291
Debt securities available for sale (at fair value)	73,869	61,617
Taxable State and Political Subdivisions General Obligations [Member]
Debt securities, available for sale, amortized cost	79,323	82,410
Available for sale securities, unrealized gains	3	9
Available for sale securities, unrealized losses	14,995	19,924
Debt securities available for sale (at fair value)	64,331	62,495
Taxable State and Political Subdivisions Various Tax Revenues [Member]
Debt securities, available for sale, amortized cost	10,665	10,699
Available for sale securities, unrealized gains	0	0
Available for sale securities, unrealized losses	2,107	2,591
Debt securities available for sale (at fair value)	8,558	8,108
Taxable State and Political Subdivisions Other Revenues [Member]
Debt securities, available for sale, amortized cost	26,822	29,044
Available for sale securities, unrealized gains	0	0
Available for sale securities, unrealized losses	4,782	6,580
Debt securities available for sale (at fair value)	22,040	22,464
Corporate Debt Securities [Member]
Debt securities, available for sale, amortized cost	39,618	33,409
Available for sale securities, unrealized gains	52	44
Available for sale securities, unrealized losses	1,763	1,825
Debt securities available for sale (at fair value)	37,907	31,628
Asset-Backed Securities [Member]
Debt securities, available for sale, amortized cost	44,388	20,009
Available for sale securities, unrealized gains	81	0
Available for sale securities, unrealized losses	264	533
Debt securities available for sale (at fair value)	44,205	19,476
Taxable Debt Securities [Member]
Debt securities, available for sale, amortized cost	436,170	317,061
Available for sale securities, unrealized gains	925	264
Available for sale securities, unrealized losses	33,793	39,862
Debt securities available for sale (at fair value)	403,302	277,463
Tax Exempt State and Political Subdivisions General Obligations [Member]
Debt securities, available for sale, amortized cost	80,144	93,910
Available for sale securities, unrealized gains	581	281
Available for sale securities, unrealized losses	3,716	6,719
Debt securities available for sale (at fair value)	77,009	87,472
Tax Exempt State and Political Subdivisions Other Revenues [Member]
Debt securities, available for sale, amortized cost	24,882	11,274
Available for sale securities, unrealized gains	28	9
Available for sale securities, unrealized losses	2,459	1,326
Debt securities available for sale (at fair value)	22,451	9,957
Tax Exempt State and Political Subdivisions Water And Sewer Revenues [Member]
Debt securities, available for sale, amortized cost		17,560
Available for sale securities, unrealized gains		120
Available for sale securities, unrealized losses		1,154
Debt securities available for sale (at fair value)		16,526
Tax Exempt Debt Securities [Member]
Debt securities, available for sale, amortized cost	105,026	138,006
Available for sale securities, unrealized gains	609	457
Available for sale securities, unrealized losses	6,175	10,725
Debt securities available for sale (at fair value)	$ 99,460	127,738
Tax Exempt State and Political Subdivisions Lease Revenues [Member]
Debt securities, available for sale, amortized cost		7,411
Available for sale securities, unrealized gains		47
Available for sale securities, unrealized losses		411
Debt securities available for sale (at fair value)		7,047
Tax Exempt State and Political Subdivisions Various Tax Revenues [Member]
Debt securities, available for sale, amortized cost		7,851
Available for sale securities, unrealized gains		0
Available for sale securities, unrealized losses		1,115
Debt securities available for sale (at fair value)		$ 6,736