Note 13 - Fair Value Measurements - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Available-for-sale debt securities, at fair value	$ 473,119	$ 476,091
Equity securities, at fair value	7,369	7,717
US Treasury Securities [Member]
Available-for-sale debt securities, at fair value	32,845	32,134
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale debt securities, at fair value	219,483	220,782
Collateralized Mortgage-Backed Securities [Member]
Available-for-sale debt securities, at fair value	19,970	20,663
Mortgage-Backed Securities, Issued by Private Enterprises [Member]
Available-for-sale debt securities, at fair value	69,740	72,507
Corporate Debt Securities [Member]
Available-for-sale debt securities, at fair value	32,040	30,672
Asset-Backed Securities [Member]
Available-for-sale debt securities, at fair value	14,278	14,941
Negotiable Certificates of Deposit [Member]
Available-for-sale debt securities, at fair value	655	656
Fair Value, Recurring [Member]
Available-for-sale debt securities, at fair value	473,119	476,091
Equity securities, at fair value	7,369	7,717
Derivative assets	1,712	2,104
Total financial assets	482,200	485,912
Derivative liabilities	2,203	931
Total financial liabilities	2,203	931
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale debt securities, at fair value	0	0
Equity securities, at fair value	7,369	7,717
Derivative assets	0	0
Total financial assets	7,369	7,717
Derivative liabilities	0	0
Total financial liabilities	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale debt securities, at fair value	465,107	468,155
Equity securities, at fair value	0	0
Derivative assets	1,712	2,104
Total financial assets	466,819	470,259
Derivative liabilities	2,203	931
Total financial liabilities	2,203	931
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale debt securities, at fair value	8,012	7,936
Equity securities, at fair value	0	0
Derivative assets	0
Total financial assets	8,012	7,936
Derivative liabilities	0	0
Total financial liabilities	0	0
Fair Value, Recurring [Member] | US Treasury Securities [Member]
Available-for-sale debt securities, at fair value	32,845	32,134
Fair Value, Recurring [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale debt securities, at fair value	32,845	32,134
Fair Value, Recurring [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member]
Available-for-sale debt securities, at fair value	219,483	220,782
Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale debt securities, at fair value	219,483	220,782
Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | Residential Mortgage [Member]
Available-for-sale debt securities, at fair value	80,750	80,407
Fair Value, Recurring [Member] | Residential Mortgage [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | Residential Mortgage [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale debt securities, at fair value	80,750	80,407
Fair Value, Recurring [Member] | Residential Mortgage [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | Commercial Loan [Member]
Available-for-sale debt securities, at fair value	3,358	3,329
Fair Value, Recurring [Member] | Commercial Loan [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | Commercial Loan [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale debt securities, at fair value	3,358	3,329
Fair Value, Recurring [Member] | Commercial Loan [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | Collateralized Mortgage-Backed Securities [Member]
Available-for-sale debt securities, at fair value	19,970	20,663
Fair Value, Recurring [Member] | Collateralized Mortgage-Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | Collateralized Mortgage-Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale debt securities, at fair value	19,970	20,663
Fair Value, Recurring [Member] | Collateralized Mortgage-Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | Mortgage-Backed Securities, Issued by Private Enterprises [Member]
Available-for-sale debt securities, at fair value	69,740	72,507
Fair Value, Recurring [Member] | Mortgage-Backed Securities, Issued by Private Enterprises [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | Mortgage-Backed Securities, Issued by Private Enterprises [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale debt securities, at fair value	69,740	72,507
Fair Value, Recurring [Member] | Mortgage-Backed Securities, Issued by Private Enterprises [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | Corporate Debt Securities [Member]
Available-for-sale debt securities, at fair value	32,040	30,672
Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale debt securities, at fair value	24,028	22,736
Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale debt securities, at fair value	8,012	7,936
Fair Value, Recurring [Member] | Asset-Backed Securities [Member]
Available-for-sale debt securities, at fair value	14,278	14,941
Fair Value, Recurring [Member] | Asset-Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | Asset-Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale debt securities, at fair value	14,278	14,941
Fair Value, Recurring [Member] | Asset-Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | Negotiable Certificates of Deposit [Member]
Available-for-sale debt securities, at fair value	655	656
Fair Value, Recurring [Member] | Negotiable Certificates of Deposit [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale debt securities, at fair value	0	0
Fair Value, Recurring [Member] | Negotiable Certificates of Deposit [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale debt securities, at fair value	655	656
Fair Value, Recurring [Member] | Negotiable Certificates of Deposit [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale debt securities, at fair value	$ 0	$ 0