Note 3 - Securities - Securities in a Continuous Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Less than 12 months, fair value	$ 21,242	$ 62,617
Less than 12 months, unrealized loss	(257)	(765)
12 months or more, fair value	36,313	57,672
12 months or more, unrealized loss	(915)	(1,586)
Fair value	57,555	120,289
Unrealized loss	(1,172)	(2,351)
US Government Agencies Debt Securities [Member]
Less than 12 months, fair value	3,934	22,007
Less than 12 months, unrealized loss	(11)	(230)
12 months or more, fair value	1,535	11,972
12 months or more, unrealized loss	(6)	(273)
Fair value	5,469	33,979
Unrealized loss	(17)	(503)
Collateralized Mortgage Obligations [Member]
Less than 12 months, fair value	0	93
Less than 12 months, unrealized loss	0	(1)
12 months or more, fair value	650	1,917
12 months or more, unrealized loss	(9)	(58)
Fair value	650	2,010
Unrealized loss	(9)	(59)
US States and Political Subdivisions Debt Securities [Member]
Less than 12 months, fair value	0	9,630
Less than 12 months, unrealized loss	0	(55)
12 months or more, fair value	411	26,559
12 months or more, unrealized loss	(1)	(369)
Fair value	411	36,189
Unrealized loss	(1)	(424)
SBA Pool [Member]
Less than 12 months, fair value	1,423	3,284
Less than 12 months, unrealized loss	(7)	(8)
12 months or more, fair value	3,545	3,726
12 months or more, unrealized loss	(26)	(39)
Fair value	4,968	7,010
Unrealized loss	(33)	(47)
Corporate Debt Securities [Member]
Less than 12 months, fair value	2,994	3,999
Less than 12 months, unrealized loss	(6)	(59)
12 months or more, fair value	8,859	11,645
12 months or more, unrealized loss	(452)	(842)
Fair value	11,853	15,644
Unrealized loss	(458)	(901)
Asset-backed Securities [Member]
Less than 12 months, fair value	12,891	23,604
Less than 12 months, unrealized loss	(233)	(412)
12 months or more, fair value	21,313	1,853
12 months or more, unrealized loss	(421)	(5)
Fair value	34,204	25,457
Unrealized loss	$ (654)	$ (417)