Note 9 - Allowance for Loan Losses and Credit Quality Information - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Dec. 31, 2019
Balance	$ 8,649	$ 8,624	$ 8,564	$ 8,686
Provision for losses	(770)	420	(1,548)	1,452
Charge-offs	(37)	(48)	(812)	(963)
Recoveries	150	39	232	1,924
Balance	9,532	8,195	9,532	8,195
Specific reserves					$ 116	$ 725
General reserves					9,416	7,839
Balance	8,649	8,195	8,564	8,686	9,532	8,564
Individually reviewed for impairment					2,997	3,851
Collectively reviewed for impairment					677,820	600,584
Ending balance					680,817	604,435
Residential Portfolio Segment [Member]
Balance	938	867	857	833
Provision for losses	(27)	(24)	(108)	(58)
Charge-offs	0	(2)	0	(2)
Recoveries	0	0	0	0
Balance	965	889	965	889
Specific reserves					31	62
General reserves					934	795
Balance	965	889	857	833	965	857
Individually reviewed for impairment					708	974
Collectively reviewed for impairment					130,135	119,090
Ending balance					130,843	120,064
Commercial Real Estate Portfolio Segment [Member]
Balance	5,382	4,762	5,060	4,869
Provision for losses	(878)	42	(1,913)	1,834
Charge-offs	0	0	(730)	0
Recoveries	0	0	17	1,685
Balance	6,260	4,720	6,260	4,720
Specific reserves					5	451
General reserves					6,255	4,609
Balance	6,260	4,720	5,060	4,869	6,260	5,060
Individually reviewed for impairment					1,537	1,166
Collectively reviewed for impairment					382,370	349,029
Ending balance					383,907	350,195
Consumer Portfolio Segment [Member]
Balance	1,464	1,632	1,507	1,622
Provision for losses	64	37	79	(13)
Charge-offs	(29)	(46)	(74)	(92)
Recoveries	5	2	22	8
Balance	1,376	1,551	1,376	1,551
Specific reserves					63	119
General reserves					1,313	1,388
Balance	1,376	1,551	1,507	1,622	1,376	1,507
Individually reviewed for impairment					707	976
Collectively reviewed for impairment					58,564	68,973
Ending balance					59,271	69,949
Commercial Portfolio Segment [Member]
Balance	865	1,363	1,140	1,362
Provision for losses	71	365	394	(311)
Charge-offs	(8)	0	(8)	(869)
Recoveries	145	37	193	231
Balance	931	1,035	931	1,035
Specific reserves					17	93
General reserves					914	1,047
Balance	$ 931	$ 1,035	$ 1,140	$ 1,362	931	1,140
Individually reviewed for impairment					45	735
Collectively reviewed for impairment					106,751	63,492
Ending balance					$ 106,796	$ 64,227