Note 6 - Fair Value Measurements - Assets and Liabilities at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Securities available for sale, at fair value	$ 596,253	$ 601,898
Fair Value, Inputs, Level 1 [Member]
Securities available for sale, at fair value	0	0
Fair Value, Inputs, Level 2 [Member]
Securities available for sale, at fair value	596,253	601,898
Fair Value, Inputs, Level 3 [Member]
Securities available for sale, at fair value	0	0
US Government Agencies Debt Securities [Member]
Securities available for sale, at fair value	306,927	311,124
US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Securities available for sale, at fair value	0	0
US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Securities available for sale, at fair value	306,927	311,124
US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Securities available for sale, at fair value	0	0
US States and Political Subdivisions Debt Securities [Member]
Securities available for sale, at fair value	147,612	145,734
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Securities available for sale, at fair value	0	0
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Securities available for sale, at fair value	147,612	145,734
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Securities available for sale, at fair value	0	0
Collateralized Mortgage-Backed Securities [Member]
Securities available for sale, at fair value	135,928	138,298
Collateralized Mortgage-Backed Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Securities available for sale, at fair value	0	0
Collateralized Mortgage-Backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Securities available for sale, at fair value	135,928	138,298
Collateralized Mortgage-Backed Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Securities available for sale, at fair value	0	0
Corporate Debt Securities [Member]
Securities available for sale, at fair value	5,786	5,743
Corporate Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Securities available for sale, at fair value	0	0
Corporate Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Securities available for sale, at fair value	5,786	5,743
Corporate Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Securities available for sale, at fair value	$ 0	0
US Treasury Securities [Member]
Securities available for sale, at fair value		999
US Treasury Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Securities available for sale, at fair value		0
US Treasury Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Securities available for sale, at fair value		999
US Treasury Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Securities available for sale, at fair value		$ 0

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 103
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-103

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
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-Section 55
-Paragraph 100
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-100

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
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-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
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Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
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Reference 8: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
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-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481830/320-10-45-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

+ Details