Note 3 - Loans - Loans Individually Evaluated for Impairment (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Average recorded investment	$ 6,077	$ 7,563
Recorded investment	5,876	6,269
Unpaid principal balance	6,741	7,527
Loans with no related allowance recorded, recorded investment	3,235	3,609
Loans with no related allowance recorded, unpaid principal balance	3,517	4,392
Loans with no related allowance recorded, average recorded investment	3,410	4,996
Loans with an allowance recorded, recorded investment	2,641	2,660
Loans with an allowance recorded, unpaid principal balance	3,224	3,135
Related allowance	985	1,267
Loans with an allowance recorded, average recorded investment	2,667	2,567
Commercial and Industrial Portfolio Segment [Member]
Average recorded investment	2,716	3,566
Recorded investment	2,624	2,682
Unpaid principal balance	3,207	3,300
Loans with no related allowance recorded, recorded investment	40	322
Loans with no related allowance recorded, unpaid principal balance	40	465
Loans with no related allowance recorded, average recorded investment	187	1,947
Loans with an allowance recorded, recorded investment	2,584	2,360
Loans with an allowance recorded, unpaid principal balance	3,167	2,835
Related allowance	928	1,207
Loans with an allowance recorded, average recorded investment	2,529	1,619
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Average recorded investment	465	290
Recorded investment	412	538
Unpaid principal balance	412	708
Loans with no related allowance recorded, recorded investment	412	538
Loans with no related allowance recorded, unpaid principal balance	412	708
Loans with no related allowance recorded, average recorded investment	465	108
Loans with an allowance recorded, recorded investment
Loans with an allowance recorded, unpaid principal balance
Related allowance
Loans with an allowance recorded, average recorded investment		182
Undevelopment Land Portfolio Segment [Member]
Average recorded investment	473	225
Recorded investment	473	474
Unpaid principal balance	473	506
Loans with no related allowance recorded, recorded investment	473	233
Loans with no related allowance recorded, unpaid principal balance	473	265
Loans with no related allowance recorded, average recorded investment	393	76
Loans with an allowance recorded, recorded investment		241
Loans with an allowance recorded, unpaid principal balance		241
Related allowance		1
Loans with an allowance recorded, average recorded investment	80	149
Real Estate Mortgage Portfolio Segment [Member]
Average recorded investment	2,365	3,401
Recorded investment	2,310	2,516
Unpaid principal balance	2,592	2,954
Loans with no related allowance recorded, recorded investment	2,310	2,516
Loans with no related allowance recorded, unpaid principal balance	2,592	2,954
Loans with no related allowance recorded, average recorded investment	2,365	2,847
Loans with an allowance recorded, recorded investment
Loans with an allowance recorded, unpaid principal balance
Related allowance
Loans with an allowance recorded, average recorded investment		554
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Average recorded investment	147	193
Recorded investment	165	107
Unpaid principal balance	171	107
Loans with no related allowance recorded, recorded investment	165	107
Loans with no related allowance recorded, unpaid principal balance	171	107
Loans with no related allowance recorded, average recorded investment	147	193
Loans with an allowance recorded, recorded investment
Loans with an allowance recorded, unpaid principal balance
Related allowance
Loans with an allowance recorded, average recorded investment
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Average recorded investment	1,196	1,910
Recorded investment	1,309	1,042
Unpaid principal balance	1,501	1,479
Loans with no related allowance recorded, recorded investment	1,309	1,042
Loans with no related allowance recorded, unpaid principal balance	1,501	1,479
Loans with no related allowance recorded, average recorded investment	1,196	1,356
Loans with an allowance recorded, recorded investment
Loans with an allowance recorded, unpaid principal balance
Related allowance
Loans with an allowance recorded, average recorded investment		554
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Average recorded investment	750	962
Recorded investment	667	895
Unpaid principal balance	740	896
Loans with no related allowance recorded, recorded investment	667	895
Loans with no related allowance recorded, unpaid principal balance	740	896
Loans with no related allowance recorded, average recorded investment	750	962
Loans with an allowance recorded, recorded investment
Loans with an allowance recorded, unpaid principal balance
Related allowance
Loans with an allowance recorded, average recorded investment
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Average recorded investment		3
Recorded investment
Unpaid principal balance
Loans with no related allowance recorded, recorded investment
Loans with no related allowance recorded, unpaid principal balance
Loans with no related allowance recorded, average recorded investment		3
Loans with an allowance recorded, recorded investment
Loans with an allowance recorded, unpaid principal balance
Related allowance
Loans with an allowance recorded, average recorded investment
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Average recorded investment	272	333
Recorded investment	169	472
Unpaid principal balance	180	472
Loans with no related allowance recorded, recorded investment	169	472
Loans with no related allowance recorded, unpaid principal balance	180	472
Loans with no related allowance recorded, average recorded investment	272	333
Loans with an allowance recorded, recorded investment
Loans with an allowance recorded, unpaid principal balance
Related allowance
Loans with an allowance recorded, average recorded investment
Consumer Portfolio Segment [Member]
Average recorded investment	58	81
Recorded investment	57	59
Unpaid principal balance	57	59
Loans with no related allowance recorded, recorded investment
Loans with no related allowance recorded, unpaid principal balance
Loans with no related allowance recorded, average recorded investment		18
Loans with an allowance recorded, recorded investment	57	59
Loans with an allowance recorded, unpaid principal balance	57	59
Related allowance	57	59
Loans with an allowance recorded, average recorded investment	$ 58	$ 63