Note 9 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($)	Jun. 30, 2026	Dec. 31, 2025
Investment securities available for sale, Estimated fair value	$ 465,991,000	$ 476,595,000
Fair Value, Recurring [Member]
Investment securities available for sale, Estimated fair value	465,991	476,595
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, Estimated fair value	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, Estimated fair value	465,991	476,595
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, Estimated fair value	0	0
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises [Member]
Investment securities available for sale, Estimated fair value	234,965,000	253,165,000
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises [Member] \| Fair Value, Recurring [Member]
Investment securities available for sale, Estimated fair value	234,965	253,165
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, Estimated fair value	0	0
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, Estimated fair value	234,965	253,165
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, Estimated fair value	0	0
Commercial Mortgage Backed Securities Issued by US Government Agencies [Member]
Investment securities available for sale, Estimated fair value	142,106,000	134,764,000
Commercial Mortgage Backed Securities Issued by US Government Agencies [Member] \| Fair Value, Recurring [Member]
Investment securities available for sale, Estimated fair value	142,106	134,764
Commercial Mortgage Backed Securities Issued by US Government Agencies [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, Estimated fair value	0	0
Commercial Mortgage Backed Securities Issued by US Government Agencies [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, Estimated fair value	142,106	134,764
Commercial Mortgage Backed Securities Issued by US Government Agencies [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, Estimated fair value	0	0
US States and Political Subdivisions Debt Securities [Member]
Investment securities available for sale, Estimated fair value	88,920,000	88,666,000
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Recurring [Member]
Investment securities available for sale, Estimated fair value	88,920	88,666
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, Estimated fair value	0	0
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, Estimated fair value	88,920	88,666
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, Estimated fair value	$ 0	$ 0

Note 9 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($)

Jun. 30, 2026

Dec. 31, 2025

Investment securities available for sale, Estimated fair value

$ 465,991,000

$ 476,595,000

Fair Value, Recurring [Member]

Investment securities available for sale, Estimated fair value

465,991

476,595

Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]

Investment securities available for sale, Estimated fair value