Note 5 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans and Associated Reserves (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Principal balance		$ 12,319	$ 9,820
Total recorded investment	[1]	11,924	9,173
Recorded investment for which there is no related allowance	[1]	10,444	8,269
Recorded investment for which there is a related allowance	[1]	1,480	904
Related allowance		177	26
Real Estate Construction Portfolio Segment[Member] | Construction, Other [Member]
Principal balance	[2]	2,882
Total recorded investment	[1],[2]	2,882
Recorded investment for which there is no related allowance	[1],[2]	2,882
Recorded investment for which there is a related allowance	[1],[2]	0
Related allowance	[2]	0
Real Estate Construction Portfolio Segment[Member] | Construction, 1-4 Family Residential [Member]
Principal balance	[2]		280
Total recorded investment	[1],[2]		270
Recorded investment for which there is no related allowance	[1],[2]		270
Recorded investment for which there is a related allowance	[1],[2]		0
Related allowance	[2]		0
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Principal balance	[2]	807	648
Total recorded investment	[1],[2]	768	609
Recorded investment for which there is no related allowance	[1],[2]	590	267
Recorded investment for which there is a related allowance	[1],[2]	178	342
Related allowance	[2]	10	14
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member]
Principal balance	[2]	174	195
Total recorded investment	[1],[2]	174	195
Recorded investment for which there is no related allowance	[1],[2]	0	0
Recorded investment for which there is a related allowance	[1],[2]	174	195
Related allowance	[2]	6	7
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Principal balance	[2]	347	73
Total recorded investment	[1],[2]	325	73
Recorded investment for which there is no related allowance	[1],[2]	325
Recorded investment for which there is a related allowance	[1],[2]	0	73
Related allowance	[2]	0	4
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Principal balance	[2]	303	1,364
Total recorded investment	[1],[2]	303	1,091
Recorded investment for which there is no related allowance	[1],[2]	303	1,091
Recorded investment for which there is a related allowance	[1],[2]
Related allowance	[2]	0	0
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Principal balance	[2]	3,619	4,005
Total recorded investment	[1],[2]	3,611	3,957
Recorded investment for which there is no related allowance	[1],[2]	3,611	3,663
Recorded investment for which there is a related allowance	[1],[2]	0	294
Related allowance	[2]	0	1
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Principal balance	[2]	2,921	2,997
Total recorded investment	[1],[2]	2,602	2,734
Recorded investment for which there is no related allowance	[1],[2]	2,602	2,734
Recorded investment for which there is a related allowance	[1],[2]	0	0
Related allowance	[2]	0	0
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Principal balance	[2]	1,236	255
Total recorded investment	[1],[2]	1,229	241
Recorded investment for which there is no related allowance	[1],[2]	126	241
Recorded investment for which there is a related allowance	[1],[2]	1,103
Related allowance	[2]	160
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Principal balance	[2]	30	3
Total recorded investment	[1],[2]	30	3
Recorded investment for which there is no related allowance	[1],[2]	5	3
Recorded investment for which there is a related allowance	[1],[2]	25
Related allowance	[2]	$ 1

[1] Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.

[2] Only classes with impaired loans are shown.