Note 3 - Investment Securities - Amortized Cost and Estimated Fair Value of Debt Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Debt Securities, Available-for-Sale, Amortized Cost	$ 275,549	$ 282,620
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	18	8
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax	19,676	24,301
Debt securities, available-for-sale, at fair value	255,891	258,327
Debt securities, held-to-maturity, at cost, net of allowance for credit losses of $5 at March 31, 2025 and December 31, 2024	17,585	16,324
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	1,383	1,396
Debt Securities, Held-to-Maturity, Fair Value	16,202	14,928
US Treasury Securities [Member]
Debt Securities, Available-for-Sale, Amortized Cost	67,674	70,934
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax	3,750	4,754
Debt securities, available-for-sale, at fair value	63,924	66,180
US Government Corporations and Agencies Securities [Member]
Debt Securities, Available-for-Sale, Amortized Cost	83,384	83,770
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax	5,000	6,253
Debt securities, available-for-sale, at fair value	78,384	77,517
Corporate Debt Securities [Member]
Debt Securities, Available-for-Sale, Amortized Cost	8,200	8,200
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	15	5
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax	422	449
Debt securities, available-for-sale, at fair value	7,793	7,756
Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member]
Debt Securities, Available-for-Sale, Amortized Cost	75,467	78,869
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	3	3
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax	7,620	9,326
Debt securities, available-for-sale, at fair value	67,850	69,546
Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-Sale, Amortized Cost	4,239	4,248
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax	243	266
Debt securities, available-for-sale, at fair value	3,996	3,982
Debt securities, held-to-maturity, at cost, net of allowance for credit losses of $5 at March 31, 2025 and December 31, 2024	14,456	13,195
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	1,059	922
Debt Securities, Held-to-Maturity, Fair Value	13,397	12,273
Taxable Municipal Bonds [Member]
Debt Securities, Available-for-Sale, Amortized Cost	36,585	36,599
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax	2,641	3,253
Debt securities, available-for-sale, at fair value	33,944	33,346
Debt securities, held-to-maturity, at cost, net of allowance for credit losses of $5 at March 31, 2025 and December 31, 2024	3,129	3,129
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	324	474
Debt Securities, Held-to-Maturity, Fair Value	$ 2,805	$ 2,655

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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