Note 2 - Securities - Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Value of Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Securities available for sale, amortized cost	$ 341,504	$ 357,407
Securities available for sale, gross unrealized gains	5,252	8,358
Securities available for sale, gross unrealized losses	(2,544)	(1,469)
Investment securities available for sale, at fair value	344,212	364,296
US States and Political Subdivisions Debt Securities [Member] \| Securities Investment [Member]
Securities available for sale, amortized cost	110,497	122,667
Securities available for sale, gross unrealized gains	3,207	5,212
Securities available for sale, gross unrealized losses	(340)	(17)
Investment securities available for sale, at fair value	113,364	127,862
International Agency Bonds [Member] \| Securities Investment [Member]
Securities available for sale, amortized cost	1,947
Securities available for sale, gross unrealized gains	0
Securities available for sale, gross unrealized losses	(27)
Investment securities available for sale, at fair value	1,920
Asset-backed Securities, Issued by US Government Agencies [Member] \| Securities Investment [Member]
Securities available for sale, amortized cost		62,934
Securities available for sale, gross unrealized gains		1,240
Securities available for sale, gross unrealized losses		(354)
Investment securities available for sale, at fair value		63,820
Asset-backed Securities, Issued by Private Enterprises [Member] \| Securities Investment [Member]
Securities available for sale, amortized cost	14,556	29,661
Securities available for sale, gross unrealized gains	0	37
Securities available for sale, gross unrealized losses	(67)	(418)
Investment securities available for sale, at fair value	14,489	29,280
Corporate Debt Securities [Member] \| Securities Investment [Member]
Securities available for sale, amortized cost	58,906	35,408
Securities available for sale, gross unrealized gains	1,450	687
Securities available for sale, gross unrealized losses	(567)	(585)
Investment securities available for sale, at fair value	59,789	35,510
US Small Business Administration Securities [Member] \| Securities Investment [Member]
Securities available for sale, amortized cost	14,404	18,420
Securities available for sale, gross unrealized gains	276	144
Securities available for sale, gross unrealized losses	0	0
Investment securities available for sale, at fair value	14,680	18,564
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Collateralized Mortgage Backed Securities [Member]
Securities available for sale, amortized cost	80,877	61,859
Securities available for sale, gross unrealized gains	248	876
Securities available for sale, gross unrealized losses	(1,163)	(52)
Investment securities available for sale, at fair value	79,962	62,683
Mortgage-backed Securities, Issued by Private Enterprises [Member] \| Collateralized Mortgage Backed Securities [Member]
Securities available for sale, amortized cost	60,317	26,458
Securities available for sale, gross unrealized gains	71	162
Securities available for sale, gross unrealized losses	(380)	(43)
Investment securities available for sale, at fair value	$ 60,008	$ 26,577

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).

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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).

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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).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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