Note 4 - Securities - Securities Available-for-sale (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Securities available-for-sale, amortized costs	$ 738,559	$ 682,467
Securities available-for-sale, gross unrealized gains	1,390	10,680
Securities available-for-sale, gross unrealized losses	40,595	7,067
Securities available for sale, at fair value	699,354	686,080
US Treasury Securities [Member]
Securities available-for-sale, amortized costs	989
Securities available-for-sale, gross unrealized gains	0
Securities available-for-sale, gross unrealized losses	25
Securities available for sale, at fair value	964
US Government Agencies Debt Securities [Member]
Securities available-for-sale, amortized costs	344,348	279,934
Securities available-for-sale, gross unrealized gains	904	2,795
Securities available-for-sale, gross unrealized losses	22,864	4,710
Securities available for sale, at fair value	322,388	278,019
US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale, amortized costs	193,185	195,365
Securities available-for-sale, gross unrealized gains	416	5,314
Securities available-for-sale, gross unrealized losses	14,801	2,007
Securities available for sale, at fair value	178,800	198,672
Collateralized Mortgage-Backed Securities [Member]
Securities available-for-sale, amortized costs	193,538	204,164
Securities available-for-sale, gross unrealized gains	70	2,323
Securities available-for-sale, gross unrealized losses	2,722	313
Securities available for sale, at fair value	190,886	206,174
Corporate Debt Securities [Member]
Securities available-for-sale, amortized costs	6,499	3,004
Securities available-for-sale, gross unrealized gains	0	248
Securities available-for-sale, gross unrealized losses	183	37
Securities available for sale, at fair value	$ 6,316	$ 3,215

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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