Note 6 - Equity and Other Investments (Details Textual)	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Federal Home Loan Bank Stock	$ 14,400,000	$ 11,300,000
Number of Limited Partnerships	4
Investment in a Limited Partnership	$ 6,600,000	4,800,000
Investment Tax Credit	1,590,000	1,309,000	$ 1,087,000
Amortization on Investment in Limited Partnership	1,162,000	1,177,000	877,000
Income Tax Benefit Recognized on Limited Partnerships	$ 200,000	$ 214,000	$ 206,000