Note 3 - Securities - Amortized Cost and Estimated Fair Values of Debt Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Available-for-sale securities, amortized cost	$ 207,330	$ 177,612
Available-for-sale securities, gross unrealized gains	1,733	2,832
Available-for-sale securities, gross unrealized losses	(2,351)	(1,196)
Available-for-sale securities, fair market value	206,712	179,248
US Government Agencies Debt Securities [Member]
Available-for-sale securities, amortized cost	44,474	29,741
Available-for-sale securities, gross unrealized gains	135	374
Available-for-sale securities, gross unrealized losses	(503)	(143)
Available-for-sale securities, fair market value	44,106	29,972
Collateralized Mortgage Obligations [Member]
Available-for-sale securities, amortized cost	2,071	2,628
Available-for-sale securities, gross unrealized gains	0	1
Available-for-sale securities, gross unrealized losses	(59)	(36)
Available-for-sale securities, fair market value	2,012	2,593
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities, amortized cost	92,257	91,201
Available-for-sale securities, gross unrealized gains	1,404	2,174
Available-for-sale securities, gross unrealized losses	(424)	(308)
Available-for-sale securities, fair market value	93,237	93,067
SBA Pool [Member]
Available-for-sale securities, amortized cost	8,707	11,818
Available-for-sale securities, gross unrealized gains	13	46
Available-for-sale securities, gross unrealized losses	(47)	(14)
Available-for-sale securities, fair market value	8,673	11,850
Corporate Debt Securities [Member]
Available-for-sale securities, amortized cost	21,426	19,358
Available-for-sale securities, gross unrealized gains	62	112
Available-for-sale securities, gross unrealized losses	(901)	(681)
Available-for-sale securities, fair market value	20,587	18,789
Asset-backed Securities [Member]
Available-for-sale securities, amortized cost	38,395	22,866
Available-for-sale securities, gross unrealized gains	119	125
Available-for-sale securities, gross unrealized losses	(417)	(14)
Available-for-sale securities, fair market value	$ 38,097	$ 22,977

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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