Note 9 - Allowance for Loan Losses and Credit Quality Information - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Dec. 31, 2019
Balance	$ 8,564	$ 8,686
Provision for losses	(460)	(27)
Charge-offs	(12)	(82)
Recoveries	24	42
Balance	9,036	8,673
Specific reserves			$ 647	$ 725
General reserves			8,389	7,839
Balance	8,564	8,673	9,036	8,564
Individually reviewed for impairment			3,639	3,851
Collectively reviewed for impairment			622,626	600,584
Ending balance			626,265	604,435
Residential Portfolio Segment [Member]
Balance	857	833
Provision for losses	(80)	(100)
Charge-offs	0	0
Recoveries	0	0
Balance	937	933
Specific reserves			46	62
General reserves			891	795
Balance	937	933	937	857
Individually reviewed for impairment			1,003	974
Collectively reviewed for impairment			124,138	119,090
Ending balance			125,141	120,064
Commercial Real Estate Portfolio Segment [Member]
Balance	5,060	4,869
Provision for losses	(479)	(13)
Charge-offs	0	0
Recoveries	0	10
Balance	5,539	4,892
Specific reserves			443	451
General reserves			5,096	4,609
Balance	5,539	4,892	5,539	5,060
Individually reviewed for impairment			1,703	1,166
Collectively reviewed for impairment			361,856	349,029
Ending balance			363,559	350,195
Consumer Portfolio Segment [Member]
Balance	1,507	1,622
Provision for losses	(87)	(3)
Charge-offs	(12)	(39)
Recoveries	1	2
Balance	1,583	1,588
Specific reserves			120	119
General reserves			1,463	1,388
Balance	1,583	1,588	1,583	1,507
Individually reviewed for impairment			802	976
Collectively reviewed for impairment			67,278	68,973
Ending balance			68,080	69,949
Commercial Portfolio Segment [Member]
Balance	1,140	1,362
Provision for losses	186	89
Charge-offs	0	(43)
Recoveries	23	30
Balance	977	1,260
Specific reserves			38	93
General reserves			939	1,047
Balance	$ 977	$ 1,260	977	1,140
Individually reviewed for impairment			131	735
Collectively reviewed for impairment			69,354	63,492
Ending balance			$ 69,485	$ 64,227