Note 3 - Securities - Securities Reconciliation (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Available-for-sale securities, amortized costs	$ 276,635	$ 283,257
Available-for-sale securities, gross unrealized gain	9,337	4,281
Available-for-sale securities, gross unrealized loss	(895)	(588)
Securities available-for-sale	285,077	286,950
Available-for-sale securities:
Available-for-sale securities, amortized costs	276,635	283,257
Available-for-sale securities, gross unrealized gain	9,337	4,281
Available-for-sale securities, gross unrealized loss	(895)	(588)
Securities available-for-sale	285,077	286,950
US Government Agencies Debt Securities [Member]
Available-for-sale securities, amortized costs	35,487	38,291
Available-for-sale securities, gross unrealized gain	575	469
Available-for-sale securities, gross unrealized loss	(19)	(27)
Securities available-for-sale	36,043	38,733
Available-for-sale securities:
Available-for-sale securities, amortized costs	35,487	38,291
Available-for-sale securities, gross unrealized gain	575	469
Available-for-sale securities, gross unrealized loss	(19)	(27)
Securities available-for-sale	36,043	38,733
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities, amortized costs	60,828	40,702
Available-for-sale securities, gross unrealized gain	2,488	1,422
Available-for-sale securities, gross unrealized loss	(53)	(26)
Securities available-for-sale	63,263	42,098
Available-for-sale securities:
Available-for-sale securities, amortized costs	60,828	40,702
Available-for-sale securities, gross unrealized gain	2,488	1,422
Available-for-sale securities, gross unrealized loss	(53)	(26)
Securities available-for-sale	63,263	42,098
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member]
Available-for-sale securities, amortized costs	155,252	179,114
Available-for-sale securities, gross unrealized gain	5,728	2,163
Available-for-sale securities, gross unrealized loss	(541)	(442)
Securities available-for-sale	160,439	180,835
Available-for-sale securities:
Available-for-sale securities, amortized costs	155,252	179,114
Available-for-sale securities, gross unrealized gain	5,728	2,163
Available-for-sale securities, gross unrealized loss	(541)	(442)
Securities available-for-sale	160,439	180,835
Corporate Debt Securities [Member]
Available-for-sale securities, amortized costs	3,001	3,005
Available-for-sale securities, gross unrealized gain	3	6
Available-for-sale securities, gross unrealized loss	(21)	(45)
Securities available-for-sale	2,983	2,966
Available-for-sale securities:
Available-for-sale securities, amortized costs	3,001	3,005
Available-for-sale securities, gross unrealized gain	3	6
Available-for-sale securities, gross unrealized loss	(21)	(45)
Securities available-for-sale	2,983	2,966
Commercial Mortgage Backed Securities [Member]
Available-for-sale securities, amortized costs	16,891	19,126
Available-for-sale securities, gross unrealized gain	543	221
Available-for-sale securities, gross unrealized loss	(6)	(40)
Securities available-for-sale	17,428	19,307
Available-for-sale securities:
Available-for-sale securities, amortized costs	16,891	19,126
Available-for-sale securities, gross unrealized gain	543	221
Available-for-sale securities, gross unrealized loss	(6)	(40)
Securities available-for-sale	17,428	19,307
Asset-backed Securities [Member]
Available-for-sale securities, amortized costs	5,176	3,019
Available-for-sale securities, gross unrealized gain
Available-for-sale securities, gross unrealized loss	(255)	(8)
Securities available-for-sale	4,921	3,011
Available-for-sale securities:
Available-for-sale securities, amortized costs	5,176	3,019
Available-for-sale securities, gross unrealized gain
Available-for-sale securities, gross unrealized loss	(255)	(8)
Securities available-for-sale	$ 4,921	$ 3,011