Note 10 - Fair Value Measurements - Fair Value on a Recurring Basis (Details) - USD ($)	Sep. 30, 2025	Dec. 31, 2024
Debt securities available-for-sale	$ 223,633,000	$ 116,053,000
Marketable equity securities	518,000	268,000
Fair Value, Recurring [Member]
Debt securities available-for-sale	223,633,000	116,053,000
Marketable equity securities	518,000	268,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Debt securities available-for-sale	2,988,000	2,202,000
Marketable equity securities	518,000	268,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Debt securities available-for-sale	220,645,000	113,851,000
Marketable equity securities	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Debt securities available-for-sale	0	0
Marketable equity securities	0	0
US Treasury Securities [Member]
Debt securities available-for-sale	2,988,000	2,202,000
US Treasury Securities [Member] | Fair Value, Recurring [Member]
Debt securities available-for-sale	2,988,000	2,202,000
US Treasury Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Debt securities available-for-sale	2,988,000	2,202,000
US Treasury Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Debt securities available-for-sale	0	0
US Treasury Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Debt securities available-for-sale	0	0
US Government Agencies Debt Securities [Member]
Debt securities available-for-sale	49,557,000	25,449,000
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member]
Debt securities available-for-sale	49,557,000	25,449,000
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Debt securities available-for-sale	0	0
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Debt securities available-for-sale	49,557,000	25,449,000
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Debt securities available-for-sale	0	0
Taxable Municipal Notes [Member]
Debt securities available-for-sale	34,165,000	5,631,000
Taxable Municipal Notes [Member] | Fair Value, Recurring [Member]
Debt securities available-for-sale	34,165,000	5,631,000
Taxable Municipal Notes [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Debt securities available-for-sale	0	0
Taxable Municipal Notes [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Debt securities available-for-sale	34,165,000	5,631,000
Taxable Municipal Notes [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Debt securities available-for-sale	0	0
Nontaxable Municipal Notes [Member]
Debt securities available-for-sale	87,435,000	51,796,000
Nontaxable Municipal Notes [Member] | Fair Value, Recurring [Member]
Debt securities available-for-sale	87,435,000	51,796,000
Nontaxable Municipal Notes [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Debt securities available-for-sale	0	0
Nontaxable Municipal Notes [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Debt securities available-for-sale	87,435,000	51,796,000
Nontaxable Municipal Notes [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Debt securities available-for-sale	0	0
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Recurring [Member]
Debt securities available-for-sale	45,468,000	27,098,000
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Debt securities available-for-sale	0	0
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Debt securities available-for-sale	45,468,000	27,098,000
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Debt securities available-for-sale	0	0
Corporate Debt Securities [Member]
Debt securities available-for-sale	4,020,000	3,877,000
Corporate Debt Securities [Member] | Fair Value, Recurring [Member]
Debt securities available-for-sale	4,020,000	3,877,000
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Debt securities available-for-sale	0	0
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Debt securities available-for-sale	4,020,000	3,877,000
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Debt securities available-for-sale	$ 0	$ 0