Note 6 - Investments and Equity Securities - Gross Unrealized Losses and Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Less than Twelve Months, Fair Value	$ 2,575	$ 94,134
Less than Twelve Months, Gross Unrealized Losses	(17)	(12,097)
Twelve Months or Greater, Fair Value	141,556	51,244
Twelve Months or Greater, Gross Unrealized Losses	(20,573)	(15,986)
Total, Fair Value	144,131	145,378
Total, Gross Unrealized Losses	(20,590)	(28,083)
Less than Twelve Months, Fair Value	2,575	94,134
Less than Twelve Months, Gross Unrealized Losses	(17)	(12,097)
Twelve Months or Greater, Fair Value	141,556	51,244
Twelve Months or Greater, Gross Unrealized Losses	(20,573)	(15,986)
Total, Fair Value	144,131	145,378
Total, Gross Unrealized Losses	(20,590)	(28,083)
Subordinated Debt Securities [Member]
Less than Twelve Months, Fair Value	994	12,638
Less than Twelve Months, Gross Unrealized Losses	(6)	(1,129)
Twelve Months or Greater, Fair Value	29,356	8,790
Twelve Months or Greater, Gross Unrealized Losses	(2,445)	(1,010)
Total, Fair Value	30,350	21,428
Total, Gross Unrealized Losses	(2,451)	(2,139)
Less than Twelve Months, Fair Value	994	12,638
Less than Twelve Months, Gross Unrealized Losses	(6)	(1,129)
Twelve Months or Greater, Fair Value	29,356	8,790
Twelve Months or Greater, Gross Unrealized Losses	(2,445)	(1,010)
Total, Fair Value	30,350	21,428
Total, Gross Unrealized Losses	(2,451)	(2,139)
Nontaxable Municipal Bonds [Member]
Less than Twelve Months, Fair Value	1,386	75,343
Less than Twelve Months, Gross Unrealized Losses	(10)	(10,488)
Twelve Months or Greater, Fair Value	106,078	41,138
Twelve Months or Greater, Gross Unrealized Losses	(17,482)	(14,623)
Total, Fair Value	107,464	116,481
Total, Gross Unrealized Losses	(17,492)	(25,111)
Less than Twelve Months, Fair Value	1,386	75,343
Less than Twelve Months, Gross Unrealized Losses	(10)	(10,488)
Twelve Months or Greater, Fair Value	106,078	41,138
Twelve Months or Greater, Gross Unrealized Losses	(17,482)	(14,623)
Total, Fair Value	107,464	116,481
Total, Gross Unrealized Losses	(17,492)	(25,111)
Mortgage-Backed Securities, Issued by US Government Sponsored Enterprises [Member]
Less than Twelve Months, Fair Value	195	6,153
Less than Twelve Months, Gross Unrealized Losses	(1)	(480)
Twelve Months or Greater, Fair Value	6,122	1,316
Twelve Months or Greater, Gross Unrealized Losses	(646)	(353)
Total, Fair Value	6,317	7,469
Total, Gross Unrealized Losses	(647)	(833)
Less than Twelve Months, Fair Value	195	6,153
Less than Twelve Months, Gross Unrealized Losses	(1)	(480)
Twelve Months or Greater, Fair Value	6,122	1,316
Twelve Months or Greater, Gross Unrealized Losses	(646)	(353)
Total, Fair Value	6,317	7,469
Total, Gross Unrealized Losses	$ (647)	$ (833)