Note 3 - Securities - Amortized Cost and Fair Value of Investments in Debt Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale, Amortized Cost	$ 694,639	$ 455,992
Securities available for sale, unrealized gains	5,086	10,261
Securities available for sale, unrealized losses	7,258	162
Securities available for sale, fair value	692,467	466,091
US Treasury Securities [Member]
Debt Securities, Available-for-sale, Amortized Cost	150,751	34,997
Securities available for sale, unrealized gains	0	1
Securities available for sale, unrealized losses	1,174	0
Securities available for sale, fair value	149,577	34,998
US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale, Amortized Cost	104,518	104,092
Securities available for sale, unrealized gains	993	1,976
Securities available for sale, unrealized losses	931	45
Securities available for sale, fair value	104,580	106,023
Collateralized Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale, Amortized Cost	357,981	246,770
Securities available for sale, unrealized gains	2,854	6,117
Securities available for sale, unrealized losses	4,525	105
Securities available for sale, fair value	356,310	252,782
US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale, Amortized Cost	65,939	57,122
Securities available for sale, unrealized gains	1,021	1,979
Securities available for sale, unrealized losses	488	2
Securities available for sale, fair value	66,472	59,099
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale, Amortized Cost	15,450	13,011
Securities available for sale, unrealized gains	218	188
Securities available for sale, unrealized losses	140	10
Securities available for sale, fair value	$ 15,528	$ 13,189

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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