Note 4 - Loans and Allowance for Loan Losses - Loans Individually Evaluated for Impairment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Average impaired loans	$ 17,708		$ 17,549
Interest income recognized	181		631
Cash basis interest recognized	181		631
Unpaid principal balance	20,503		20,503		$ 25,176
Recorded investment	17,689		17,689		22,709
Allowance for Loan Losses Allocated	98		98		2,981
Average impaired loans - with no allowance recorded		$ 20,013		$ 18,995
Interest income recognized - with no allowance recorded		418		586
Cash basis interest recognized - with no allowance recorded		418		586
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Interest income recognized - with allowance recorded	5	5	14	10
Cash basis interest recognized - with allowance recorded	5	5	14	10
Unpaid principal balance - with allowance recorded	377		377		384
Recorded investment - with allowance recorded	377		377		384
Unpaid principal balance - with no allowance recorded	5,229		5,229		5,078
Recorded investment - with no allowance recorded	3,773		3,773		3,632
Allowance for Loan Losses Allocated	97		97		100
Average impaired loans - with no allowance recorded	3,779	3,378	3,730	3,176
Interest income recognized - with no allowance recorded	21	29	74	42
Cash basis interest recognized - with no allowance recorded	21	29	74	42
Average impaired loans - with allowance recorded	379	392	380	393
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Interest income recognized - with allowance recorded		143		147
Cash basis interest recognized - with allowance recorded		143		147
Unpaid principal balance - with allowance recorded					5,477
Recorded investment - with allowance recorded					5,477
Unpaid principal balance - with no allowance recorded	3,164		3,164		3,638
Recorded investment - with no allowance recorded	2,665		2,665		3,091
Allowance for Loan Losses Allocated					2,435
Average impaired loans - with no allowance recorded	2,836	3,197	2,921	3,220
Interest income recognized - with no allowance recorded	36	40	120	83
Cash basis interest recognized - with no allowance recorded	36	40	120	83
Average impaired loans - with allowance recorded		2,570		1,781
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Interest income recognized - with allowance recorded	5		108
Cash basis interest recognized - with allowance recorded	5		108
Unpaid principal balance - with no allowance recorded	993		993		1,001
Recorded investment - with no allowance recorded	447		447		527
Average impaired loans - with no allowance recorded		431		514
Interest income recognized - with no allowance recorded		97		97
Cash basis interest recognized - with no allowance recorded		97		97
Average impaired loans - with allowance recorded	487		501
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Interest income recognized - with allowance recorded	2	2	5	4
Cash basis interest recognized - with allowance recorded	2	2	5	4
Unpaid principal balance - with allowance recorded	209		209		416
Recorded investment - with allowance recorded	209		209		416
Allowance for Loan Losses Allocated	1		1		205
Average impaired loans - with allowance recorded	209	218	210	218
Residential Portfolio Segment [Member]
Unpaid principal balance - with no allowance recorded	1,141		1,141		717
Recorded investment - with no allowance recorded	1,141		1,141		717
Average impaired loans - with no allowance recorded	1,028	728	992	730
Interest income recognized - with no allowance recorded	12	7	20	16
Cash basis interest recognized - with no allowance recorded	12	7	20	16
Commercial and Industrial Portfolio Segment [Member]
Interest income recognized - with allowance recorded	100		290
Cash basis interest recognized - with allowance recorded	100		290
Unpaid principal balance - with allowance recorded					392
Recorded investment - with allowance recorded					392
Unpaid principal balance - with no allowance recorded	9,390		9,390		8,073
Recorded investment - with no allowance recorded	9,077		9,077		8,073
Allowance for Loan Losses Allocated					$ 241
Average impaired loans - with no allowance recorded		8,212		8,076
Interest income recognized - with no allowance recorded		95		187
Cash basis interest recognized - with no allowance recorded		95		187
Average impaired loans - with allowance recorded	$ 8,990	$ 887	$ 8,815	$ 887