Note 4 - Investment Securities - Available-for-sale and Held-to-maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Available-for-sale, amortized cost	$ 135,656	$ 155,473
Available-for-sale, gross unrealized gains	174	495
Available-for-sale, gross unrealized losses	(3,343)	(2,097)
Available-for-sale, estimated fair value	132,487	153,871
Held-to-maturity, amortized cost	21,462	26,279
Held-to-maturity, gross unrealized gains		13
Held-to-maturity, gross unrealized losses	(610)	(343)
Held-to-maturity, estimated fair value	20,852	25,949
Residential Mortgage Backed Securities [Member]
Available-for-sale, amortized cost	73,859	83,360
Available-for-sale, gross unrealized gains	113	286
Available-for-sale, gross unrealized losses	(1,517)	(860)
Available-for-sale, estimated fair value	72,455	82,786
Commercial Mortgage Backed Securities [Member]
Available-for-sale, amortized cost	56,101	67,281
Available-for-sale, gross unrealized gains	10	27
Available-for-sale, gross unrealized losses	(1,822)	(1,234)
Available-for-sale, estimated fair value	54,289	66,074
Held-to-maturity, amortized cost	11,716	15,065
Held-to-maturity, gross unrealized gains		1
Held-to-maturity, gross unrealized losses	(349)	(186)
Held-to-maturity, estimated fair value	11,367	14,880
US Government Agencies Debt Securities [Member]
Held-to-maturity, amortized cost	8,026	9,326
Held-to-maturity, gross unrealized gains		7
Held-to-maturity, gross unrealized losses	(244)	(144)
Held-to-maturity, estimated fair value	7,782	9,189
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale, amortized cost	5,617	4,752
Available-for-sale, gross unrealized gains	51	182
Available-for-sale, gross unrealized losses	(4)	(3)
Available-for-sale, estimated fair value	5,664	4,931
Held-to-maturity, amortized cost	1,720	1,888
Held-to-maturity, gross unrealized gains		5
Held-to-maturity, gross unrealized losses	(17)	(13)
Held-to-maturity, estimated fair value	1,703	1,880
US Treasury Securities [Member]
Available-for-sale, amortized cost	79	80
Available-for-sale, gross unrealized gains
Available-for-sale, gross unrealized losses
Available-for-sale, estimated fair value	$ 79	$ 80

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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