Note 3 - Debt and Equity Securities - Debt and Equity Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Loans, allowance for loan losses	$ 616,063	$ 570,842
Securities, Available-for-sale, Gross Unrealized Gains	7,677	10,875
Securities, Available-for-sale, Gross Unrealized Losses	9,808	1,174
Debt Securities, Available-for-sale, Total	613,932	580,543
US Government-sponsored Enterprises Debt Securities [Member]
Loans, allowance for loan losses	127,112	125,712
Securities, Available-for-sale, Gross Unrealized Gains	109	328
Securities, Available-for-sale, Gross Unrealized Losses	3,196	135
Debt Securities, Available-for-sale, Total	124,025	125,905
Collateralized Mortgage Backed Securities [Member]
Loans, allowance for loan losses	287,126	258,774
Securities, Available-for-sale, Gross Unrealized Gains	4,825	5,636
Securities, Available-for-sale, Gross Unrealized Losses	3,289	620
Debt Securities, Available-for-sale, Total	288,662	263,790
Asset-backed Securities [Member]
Loans, allowance for loan losses	39,755	36,394
Securities, Available-for-sale, Gross Unrealized Gains	397	582
Securities, Available-for-sale, Gross Unrealized Losses	22	19
Debt Securities, Available-for-sale, Total	40,130	36,957
Corporate Debt Securities [Member]
Loans, allowance for loan losses	2,500	2,500
Securities, Available-for-sale, Gross Unrealized Gains	44	100
Securities, Available-for-sale, Gross Unrealized Losses	0	0
Debt Securities, Available-for-sale, Total	2,544	2,600
US States and Political Subdivisions Debt Securities [Member]
Loans, allowance for loan losses	159,570	147,462
Securities, Available-for-sale, Gross Unrealized Gains	2,302	4,229
Securities, Available-for-sale, Gross Unrealized Losses	3,301	400
Debt Securities, Available-for-sale, Total	$ 158,571	$ 151,291

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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