Note 3 - Debt and Equity Securities - Debt and Equity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Available-for-sale, amortized cost	$ 420,207	$ 295,683
Securities, Available-for-sale, Gross Unrealized Gains	2,908	41
Securities, Available-for-sale, Gross Unrealized Losses	1,970	10,472
Debt Securities, Available-for-sale, Total	421,145	285,252
US Government-sponsored Enterprises Debt Securities [Member]
Available-for-sale, amortized cost	59,735	71,446
Securities, Available-for-sale, Gross Unrealized Gains	48	0
Securities, Available-for-sale, Gross Unrealized Losses	204	2,979
Debt Securities, Available-for-sale, Total	59,579	68,467
Collateralized Mortgage Backed Securities [Member]
Available-for-sale, amortized cost	265,648	152,375
Securities, Available-for-sale, Gross Unrealized Gains	2,300	9
Securities, Available-for-sale, Gross Unrealized Losses	635	4,874
Debt Securities, Available-for-sale, Total	267,313	147,510
Asset-backed Securities [Member]
Available-for-sale, amortized cost	27,531	22,534
Securities, Available-for-sale, Gross Unrealized Gains	1	10
Securities, Available-for-sale, Gross Unrealized Losses	303	844
Debt Securities, Available-for-sale, Total	27,229	21,700
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale, amortized cost	67,293	49,328
Securities, Available-for-sale, Gross Unrealized Gains	559	22
Securities, Available-for-sale, Gross Unrealized Losses	828	1,775
Debt Securities, Available-for-sale, Total	$ 67,024	$ 47,575

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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