Note 20 - Parent Company Only Condensed Financial Statements - Consolidated Balance Sheet Data (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	$ 135,200	$ 163,072
Interest Receivable	5,374	5,512
Total Assets	1,611,773	1,549,671
Balance	182,389	172,362	$ 160,233
Total Liabilities and Shareholders' Equity	1,611,773	1,549,671
Parent Company [Member]
Cash	28,009	26,842
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	40,881	50,211
Interest Receivable	122	200
Accounts Receivable and Other Assets	77	11,163
Total Assets	198,078	204,850
Accounts Payable and Other Liabilities	534	833
Long-term Debt	15,155	31,655
Balance	182,389	172,362
Total Liabilities and Shareholders' Equity	198,078	204,850
Parent Company [Member] | Security Federal Statutory Trust [Member]
Consolidated investment	155	155
Parent Company [Member] | Security Federal Bank [Member]
Consolidated investment	$ 128,834	$ 116,279