Note 4 - Securities - Securities Reconciliation (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Available-for-sale securities, amortized costs	$ 283,257	$ 261,198
Available-for-sale securities, gross unrealized gain	4,281	1,431
Available-for-sale securities, gross unrealized loss	(588)	(5,701)
Securities available-for-sale	286,950	256,928
Available-for-sale securities:
Available-for-sale securities, amortized costs	283,257	261,198
Available-for-sale securities, gross unrealized gain	4,281	1,431
Available-for-sale securities, gross unrealized loss	(588)	(5,701)
Securities available-for-sale	286,950	256,928
US Government Agencies Debt Securities [Member]
Available-for-sale securities, amortized costs	38,291	40,215
Available-for-sale securities, gross unrealized gain	469	202
Available-for-sale securities, gross unrealized loss	(27)	(330)
Securities available-for-sale	38,733	40,087
Available-for-sale securities:
Available-for-sale securities, amortized costs	38,291	40,215
Available-for-sale securities, gross unrealized gain	469	202
Available-for-sale securities, gross unrealized loss	(27)	(330)
Securities available-for-sale	38,733	40,087
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities, amortized costs	40,702	50,037
Available-for-sale securities, gross unrealized gain	1,422	1,082
Available-for-sale securities, gross unrealized loss	(26)	(589)
Securities available-for-sale	42,098	50,530
Available-for-sale securities:
Available-for-sale securities, amortized costs	40,702	50,037
Available-for-sale securities, gross unrealized gain	1,422	1,082
Available-for-sale securities, gross unrealized loss	(26)	(589)
Securities available-for-sale	42,098	50,530
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member]
Available-for-sale securities, amortized costs	179,114	142,355
Available-for-sale securities, gross unrealized gain	2,163	129
Available-for-sale securities, gross unrealized loss	(442)	(3,981)
Securities available-for-sale	180,835	138,503
Available-for-sale securities:
Available-for-sale securities, amortized costs	179,114	142,355
Available-for-sale securities, gross unrealized gain	2,163	129
Available-for-sale securities, gross unrealized loss	(442)	(3,981)
Securities available-for-sale	180,835	138,503
Corporate Debt Securities [Member]
Available-for-sale securities, amortized costs	3,005	3,022
Available-for-sale securities, gross unrealized gain	6
Available-for-sale securities, gross unrealized loss	(45)	(100)
Securities available-for-sale	2,966	2,922
Available-for-sale securities:
Available-for-sale securities, amortized costs	3,005	3,022
Available-for-sale securities, gross unrealized gain	6
Available-for-sale securities, gross unrealized loss	(45)	(100)
Securities available-for-sale	2,966	2,922
Commercial Mortgage Backed Securities [Member]
Available-for-sale securities, amortized costs	19,126	25,446
Available-for-sale securities, gross unrealized gain	221	17
Available-for-sale securities, gross unrealized loss	(40)	(701)
Securities available-for-sale	19,307	24,762
Available-for-sale securities:
Available-for-sale securities, amortized costs	19,126	25,446
Available-for-sale securities, gross unrealized gain	221	17
Available-for-sale securities, gross unrealized loss	(40)	(701)
Securities available-for-sale	19,307	24,762
Asset-backed Securities [Member]
Available-for-sale securities, amortized costs	3,019	123
Available-for-sale securities, gross unrealized gain		1
Available-for-sale securities, gross unrealized loss	(8)
Securities available-for-sale	3,011	124
Available-for-sale securities:
Available-for-sale securities, amortized costs	3,019	123
Available-for-sale securities, gross unrealized gain		1
Available-for-sale securities, gross unrealized loss	(8)
Securities available-for-sale	$ 3,011	$ 124