Note 3 - Investment Securities - Schedule of Investment Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Available for sale securities, amortized cost	$ 364,252	$ 363,433
Available for sale securities, gross unrealized gains	917	321
Available for sale securities, gross unrealized losses	(7,280)	(10,688)
Available for Sale, at Fair Value	357,889	353,066
US Government Agencies Debt Securities [Member]
Available for sale securities, amortized cost	357,480	356,498
Available for sale securities, gross unrealized gains	883	303
Available for sale securities, gross unrealized losses	(7,225)	(10,596)
Available for Sale, at Fair Value	351,138	346,205
US States and Political Subdivisions Debt Securities [Member]
Available for sale securities, amortized cost	3,873	4,008
Available for sale securities, gross unrealized gains	34	18
Available for sale securities, gross unrealized losses	(12)	(37)
Available for Sale, at Fair Value	3,895	3,989
Corporate Debt Securities [Member]
Available for sale securities, amortized cost	2,899	2,927
Available for sale securities, gross unrealized gains
Available for sale securities, gross unrealized losses	(43)	(55)
Available for Sale, at Fair Value	$ 2,856	$ 2,872

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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