Note 3 - Loans - Loans Individually Evaluated for Impairment (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Loans with no related allowance recorded, recorded investment	$ 3,436	$ 7,332
Loans with no related allowance recorded, unpaid principal balance	4,200	9,072
Loans with no related allowance recorded, average recorded investment	5,758	4,304
Loans with an allowance recorded, recorded investment	3,803	48
Loans with an allowance recorded, unpaid principal balance	4,981	48
Related allowance	677	48
Loans with an allowance recorded, average recorded investment	3,204	1,981
Recorded investment	7,239	7,380
Unpaid principal balance	9,181	9,120
Average recorded investment	8,962	6,285
Commercial and Industrial Portfolio Segment [Member]
Loans with no related allowance recorded, recorded investment	238	1,142
Loans with no related allowance recorded, unpaid principal balance	321	2,202
Loans with no related allowance recorded, average recorded investment	531	411
Loans with an allowance recorded, recorded investment	2,211	34
Loans with an allowance recorded, unpaid principal balance	3,389	34
Related allowance	349	34
Loans with an allowance recorded, average recorded investment	2,061	1,882
Recorded investment	2,449	1,176
Unpaid principal balance	3,710	2,236
Average recorded investment	2,592	2,293
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans with no related allowance recorded, recorded investment	380	664
Loans with no related allowance recorded, unpaid principal balance	550	834
Loans with no related allowance recorded, average recorded investment	571	559
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
Recorded investment	380	664
Unpaid principal balance	550	834
Average recorded investment	571	559
Undevelopment Land Portfolio Segment [Member]
Loans with no related allowance recorded, recorded investment	474	474
Loans with no related allowance recorded, unpaid principal balance	506	506
Loans with no related allowance recorded, average recorded investment	474	425
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	32	48
Recorded investment	474	474
Unpaid principal balance	506	506
Average recorded investment	506	473
Real Estate Mortgage Portfolio Segment [Member]
Loans with no related allowance recorded, recorded investment	2,344	5,052
Loans with no related allowance recorded, unpaid principal balance	2,823	5,530
Loans with no related allowance recorded, average recorded investment	4,152	2,909
Loans with an allowance recorded, recorded investment	1,592	14
Loans with an allowance recorded, unpaid principal balance	1,592	14
Related allowance	328	14
Loans with an allowance recorded, average recorded investment	1,111	5
Recorded investment	3,936	5,066
Unpaid principal balance	4,415	5,544
Average recorded investment	5,263	2,914
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans with no related allowance recorded, recorded investment		52
Loans with no related allowance recorded, unpaid principal balance		53
Loans with no related allowance recorded, average recorded investment	17	110
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
Recorded investment		52
Unpaid principal balance		53
Average recorded investment	17	110
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans with no related allowance recorded, recorded investment	1,232	3,332
Loans with no related allowance recorded, unpaid principal balance	1,690	3,789
Loans with no related allowance recorded, average recorded investment	2,667	1,678
Loans with an allowance recorded, recorded investment	1,578
Loans with an allowance recorded, unpaid principal balance	1,578
Related allowance	314
Loans with an allowance recorded, average recorded investment	1,097
Recorded investment	2,810	3,332
Unpaid principal balance	3,268	3,789
Average recorded investment	3,764
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans with no related allowance recorded, recorded investment	1,107	1,637
Loans with no related allowance recorded, unpaid principal balance	1,128	1,657
Loans with no related allowance recorded, average recorded investment	1,446	935
Loans with an allowance recorded, recorded investment	14	14
Loans with an allowance recorded, unpaid principal balance	14	14
Related allowance	14	14
Loans with an allowance recorded, average recorded investment	14	5
Recorded investment	1,121	1,651
Unpaid principal balance	1,142	1,671
Average recorded investment	1,460	940
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
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
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
Recorded investment
Unpaid principal balance
Average recorded investment
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans with no related allowance recorded, recorded investment	5	31
Loans with no related allowance recorded, unpaid principal balance	5	31
Loans with no related allowance recorded, average recorded investment	22	186
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
Recorded investment	5	31
Unpaid principal balance	5	31
Average recorded investment	22	186
Consumer Portfolio Segment [Member]
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	30
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		46
Recorded investment
Unpaid principal balance
Average recorded investment	$ 30	$ 46