Note 13 - Fair Value Measurements - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Available-for-sale debt securities, at fair value	$ 442,120	$ 450,814
Equity securities, at fair value	4,373	4,786
US Treasury Securities [Member]
Available-for-sale debt securities, at fair value	32,914	33,177
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale debt securities, at fair value	195,740	199,796
Collateralized Mortgage-Backed Securities [Member]
Available-for-sale debt securities, at fair value	15,531	16,446
Mortgage-Backed Securities, Issued by Private Enterprises [Member]
Available-for-sale debt securities, at fair value	66,302	70,152
Corporate Debt Securities [Member]
Available-for-sale debt securities, at fair value	31,564	31,286
Asset-Backed Securities [Member]
Available-for-sale debt securities, at fair value	23,214	21,690
Negotiable Certificates of Deposit [Member]
Available-for-sale debt securities, at fair value	682	674
Fair Value, Recurring [Member]
Available-for-sale debt securities, at fair value	442,120	450,814
Equity securities, at fair value	4,373	4,786
Derivative assets	4,170	2,088
Total financial assets	450,663	457,688
Derivative liabilities	1,650	2,691
Total financial liabilities	1,650	2,691
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	4,373	4,786
Derivative assets	0	0
Total financial assets	4,373	4,786
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	435,012	443,840
Equity securities, at fair value	0	0
Derivative assets	4,170	2,088
Total financial assets	439,182	445,928
Derivative liabilities	1,650	2,691
Total financial liabilities	1,650	2,691
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale debt securities, at fair value	7,108	6,974
Equity securities, at fair value	0	0
Derivative assets	0
Total financial assets	7,108	6,974
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	32,914	33,177
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	32,914	33,177
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	195,740	199,796
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	195,740	199,796
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	72,803	74,207
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	72,803	74,207
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	3,370	3,386
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	3,370	3,386
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	15,531	16,446
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	15,531	16,446
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	66,302	70,151
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	66,302	70,151
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	31,564	31,286
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	24,456	24,312
Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale debt securities, at fair value	7,108	6,974
Fair Value, Recurring [Member] | Asset-Backed Securities [Member]
Available-for-sale debt securities, at fair value	23,214	21,690
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	23,214	21,690
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	682	674
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	682	674
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