Note 4 - Securities - Securities Reconciliation (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Available-for-sale securities, amortized costs	$ 261,198	$ 267,395
Available-for-sale securities, gross unrealized gain	1,431	2,221
Available-for-sale securities, gross unrealized loss	(5,701)	(2,673)
Securities available-for-sale	256,928	266,943
US Government Agencies Debt Securities [Member]
Available-for-sale securities, amortized costs	40,215	40,319
Available-for-sale securities, gross unrealized gain	202	196
Available-for-sale securities, gross unrealized loss	(330)	(146)
Securities available-for-sale	40,087	40,369
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities, amortized costs	50,037	77,412
Available-for-sale securities, gross unrealized gain	1,082	1,910
Available-for-sale securities, gross unrealized loss	(589)	(478)
Securities available-for-sale	50,530	78,844
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member]
Available-for-sale securities, amortized costs	142,355	116,061
Available-for-sale securities, gross unrealized gain	129	69
Available-for-sale securities, gross unrealized loss	(3,981)	(1,538)
Securities available-for-sale	138,503	114,592
Corporate Debt Securities [Member]
Available-for-sale securities, amortized costs	3,022	5,079
Available-for-sale securities, gross unrealized gain		18
Available-for-sale securities, gross unrealized loss	(100)	(105)
Securities available-for-sale	2,922	4,992
Commercial Mortgage Backed Securities [Member]
Available-for-sale securities, amortized costs	25,446	26,995
Available-for-sale securities, gross unrealized gain	17	24
Available-for-sale securities, gross unrealized loss	(701)	(378)
Securities available-for-sale	24,762	26,641
Asset-backed Securities [Member]
Available-for-sale securities, amortized costs	123	1,529
Available-for-sale securities, gross unrealized gain	1	4
Available-for-sale securities, gross unrealized loss		(28)
Securities available-for-sale	$ 124	$ 1,505