Note 3 - Securities - Amortized Cost and Fair Value of Investments in Debt Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Securities available for sale, amortized cost	$ 311,788	$ 375,494
Securities available for sale, unrealized gains	10,871	4,360
Securities available for sale, unrealized losses	136	659
Debt Securities, Available-for-sale, Total	322,523	379,195
US Treasury Securities [Member]
Securities available for sale, amortized cost	9,998	14,992
Securities available for sale, unrealized gains	0	0
Securities available for sale, unrealized losses	0	5
Debt Securities, Available-for-sale, Total	9,998	14,987
US Government-sponsored Enterprises Debt Securities [Member]
Securities available for sale, amortized cost	51,382	126,829
Securities available for sale, unrealized gains	2,088	1,504
Securities available for sale, unrealized losses	32	219
Debt Securities, Available-for-sale, Total	53,438	128,114
Collateralized Mortgage Backed Securities [Member]
Securities available for sale, amortized cost	193,961	182,732
Securities available for sale, unrealized gains	6,988	1,901
Securities available for sale, unrealized losses	30	393
Debt Securities, Available-for-sale, Total	200,919	184,240
US States and Political Subdivisions Debt Securities [Member]
Securities available for sale, amortized cost	44,935	41,427
Securities available for sale, unrealized gains	1,751	769
Securities available for sale, unrealized losses	6	42
Debt Securities, Available-for-sale, Total	46,680	42,154
Corporate Debt Securities [Member]
Securities available for sale, amortized cost	11,512	9,514
Securities available for sale, unrealized gains	44	186
Securities available for sale, unrealized losses	68	0
Debt Securities, Available-for-sale, Total	$ 11,488	$ 9,700

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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Amortized cost of 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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