Note 2 - Securities - Available-for-sale Securities (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Amortized cost	$ 597,463,000	$ 380,403,000
Securities available for sale, gross unrealized gains	5,238,000	7,843,000
Securities available for sale, gross unrealized losses	(9,958,000)	(899,000)
Fair value	592,743,000	387,347,000
US Government Agencies Debt Securities [Member]
Amortized cost	398,874,000	242,522,000
Securities available for sale, gross unrealized gains	266,000	516,000
Securities available for sale, gross unrealized losses	(8,769,000)	(897,000)
Fair value	390,371,000	242,141,000
Collateralized Mortgage Backed Securities [Member]
Amortized cost	41,906,000	23,869,000
Securities available for sale, gross unrealized gains	549,000	1,021,000
Securities available for sale, gross unrealized losses	(652,000)	0
Fair value	41,803,000	24,890,000
Municipal General Obligation Bonds [Member]
Amortized cost	133,894,000	101,991,000
Securities available for sale, gross unrealized gains	4,092,000	5,833,000
Securities available for sale, gross unrealized losses	(392,000)	0
Fair value	137,594,000	107,824,000
Municipal Revenue Bonds [Member]
Amortized cost	22,289,000	11,521,000
Securities available for sale, gross unrealized gains	331,000	473,000
Securities available for sale, gross unrealized losses	(145,000)	(2,000)
Fair value	22,475,000	11,992,000
Other Debt and Equity Securities [Member]
Amortized cost	500,000	500,000
Securities available for sale, gross unrealized gains	0	0
Securities available for sale, gross unrealized losses	0	0
Fair value	$ 500,000	$ 500,000

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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