Note 5 - Debt Securities - Summary of Volume of State and Political Subdivision Securities Held in Portfolio (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt securities, available for sale, amortized cost	$ 541,196	$ 455,067
Available for sale securities, unrealized gains	1,534	721
Available for sale securities, unrealized losses	39,968	50,587
Debt securities available for sale (at fair value)	502,762	$ 405,201
CALIFORNIA
Debt securities, available for sale, amortized cost	43,903
Available for sale securities, unrealized gains	0
Available for sale securities, unrealized losses	8,423
Debt securities available for sale (at fair value)	35,480
TEXAS
Debt securities, available for sale, amortized cost	29,284
Available for sale securities, unrealized gains	220
Available for sale securities, unrealized losses	3,604
Debt securities available for sale (at fair value)	25,900
MICHIGAN
Debt securities, available for sale, amortized cost	18,749
Available for sale securities, unrealized gains	8
Available for sale securities, unrealized losses	1,481
Debt securities available for sale (at fair value)	17,276
OREGON
Debt securities, available for sale, amortized cost	14,719
Available for sale securities, unrealized gains	0
Available for sale securities, unrealized losses	3,006
Debt securities available for sale (at fair value)	11,713
PENNSYLVANIA
Debt securities, available for sale, amortized cost	11,214
Available for sale securities, unrealized gains	19
Available for sale securities, unrealized losses	1,231
Debt securities available for sale (at fair value)	$ 10,002

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on 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/disclosureRef
-Topic 320
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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 10
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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
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