Note 5 - Fair Value Measurements - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Available for sale securities	$ 640,416	$ 648,513
US Treasury Securities [Member]
Available for sale securities	158,963	167,715
US Government Agencies Debt Securities [Member]
Available for sale securities	86,624	83,433
Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member]
Available for sale securities	89,240	91,050
US States and Political Subdivisions Debt Securities [Member]
Available for sale securities	245,561	245,562
Corporate Debt Securities [Member]
Available for sale securities	60,028	60,753
Fair Value, Recurring [Member]
Loans receivable	7,990	7,923
Derivative financial instruments	876	996
Derivative financial instruments, liabilities	351	248
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Loans receivable	0	0
Derivative financial instruments	0	0
Derivative financial instruments, liabilities	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Loans receivable	7,990	7,923
Derivative financial instruments	876	996
Derivative financial instruments, liabilities	351	248
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Loans receivable	0	0
Derivative financial instruments	0	0
Derivative financial instruments, liabilities	0	0
Fair Value, Recurring [Member] \| US Treasury Securities [Member]
Available for sale securities	158,963	167,715
Fair Value, Recurring [Member] \| US Treasury Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Available for sale securities	158,963	167,715
Fair Value, Recurring [Member] \| US Treasury Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale securities	0	0
Fair Value, Recurring [Member] \| US Treasury Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Available for sale securities	0	0
Fair Value, Recurring [Member] \| US Government Agencies Debt Securities [Member]
Available for sale securities	86,624	83,433
Fair Value, Recurring [Member] \| US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Available for sale securities	0	0
Fair Value, Recurring [Member] \| US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale securities	86,624	83,433
Fair Value, Recurring [Member] \| US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Available for sale securities	0	0
Fair Value, Recurring [Member] \| Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member]
Available for sale securities	89,240	91,050
Fair Value, Recurring [Member] \| Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member] \| Fair Value, Inputs, Level 1 [Member]
Available for sale securities	0	0
Fair Value, Recurring [Member] \| Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale securities	89,240	91,050
Fair Value, Recurring [Member] \| Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member] \| Fair Value, Inputs, Level 3 [Member]
Available for sale securities	0	0
Fair Value, Recurring [Member] \| US States and Political Subdivisions Debt Securities [Member]
Available for sale securities	245,561	245,562
Fair Value, Recurring [Member] \| US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Available for sale securities	0	0
Fair Value, Recurring [Member] \| US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale securities	245,561	245,562
Fair Value, Recurring [Member] \| US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Available for sale securities	0	0
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member]
Available for sale securities	60,028	60,753
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Available for sale securities	0	0
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale securities	60,028	60,753
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Available for sale securities	$ 0	$ 0