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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Dec. 31, 2018
Balance	$ 8,624	$ 9,328	$ 8,686	$ 9,311
Provision for losses	(420)	(652)	(1,452)	(482)
Charge-offs	(48)	(31)	(963)	(435)
Recoveries	39	187	1,924	438
Balance	8,195	8,832	8,195	8,832
Specific reserves					$ 667	$ 794
General reserves					7,528	7,892
Balance	8,195	9,328	8,195	8,832	8,195	8,686
Individually reviewed for impairment					3,272	3,696
Collectively reviewed for impairment					587,490	591,160
Ending balance					590,762	594,856
Residential Portfolio Segment [Member]
Balance	867	881	833	900
Provision for losses	24	(10)	58	(6)
Charge-offs	(2)	0	(2)	(24)
Recoveries	0	0	0	1
Balance	889	871	889	871
Specific reserves					52	98
General reserves					837	735
Balance	867	881	889	871	889	833
Individually reviewed for impairment					908	1,226
Collectively reviewed for impairment					112,154	109,472
Ending balance					113,062	110,698
Commercial Real Estate Portfolio Segment [Member]
Balance	4,762	5,242	4,869	5,073
Provision for losses	(42)	(287)	(1,834)	(316)
Charge-offs	0	0	0	0
Recoveries	0	0	1,685	198
Balance	4,720	4,955	4,720	4,955
Specific reserves					459	451
General reserves					4,261	4,418
Balance	4,762	5,242	4,720	4,955	4,720	4,869
Individually reviewed for impairment					1,291	1,311
Collectively reviewed for impairment					336,954	334,819
Ending balance					338,245	336,130
Consumer Portfolio Segment [Member]
Balance	1,632	1,623	1,622	1,630
Provision for losses	(37)	61	13	169
Charge-offs	(46)	(16)	(92)	(141)
Recoveries	2	5	8	15
Balance	1,551	1,673	1,551	1,673
Specific reserves					101	172
General reserves					1,450	1,450
Balance	1,632	1,623	1,551	1,673	1,551	1,622
Individually reviewed for impairment					838	856
Collectively reviewed for impairment					72,287	71,676
Ending balance					73,125	72,532
Commercial Portfolio Segment [Member]
Balance	1,363	1,582	1,362	1,708
Provision for losses	(365)	(416)	311	(329)
Charge-offs	0	(15)	(869)	(270)
Recoveries	37	182	231	224
Balance	1,035	1,333	1,035	1,333
Specific reserves					55	73
General reserves					980	1,289
Balance	$ 1,363	$ 1,582	$ 1,035	$ 1,333	1,035	1,362
Individually reviewed for impairment					235	303
Collectively reviewed for impairment					66,095	75,193
Ending balance					$ 66,330	$ 75,496