Note 5 - Loans - Loans Individually Evaluated for Impairment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Loans with no related allowance recorded, recorded investment	$ 2,611	$ 7,332
Loans with no related allowance recorded, unpaid principal balance	3,766	9,072
Loans with no related allowance recorded, average recorded investment	3,948	4,304
Loans with no related allowance recorded, interest income recognized
Loans with an allowance recorded, recorded investment	42	48
Loans with an allowance recorded, unpaid principal balance	42	48
Related allowance	42	48
Loans with an allowance recorded, average recorded investment	2,786	1,981
Loans with an allowance recorded, interest income recognized	3	78
Recorded investment	2,653	7,380
Unpaid principal balance	3,808	9,120
Average recorded investment	6,734	6,285
Interest income recognized	3	78
Commercial and Industrial Portfolio Segment [Member]
Loans with no related allowance recorded, recorded investment	192	1,142
Loans with no related allowance recorded, unpaid principal balance	707	2,202
Loans with no related allowance recorded, average recorded investment	161	411
Loans with no related allowance recorded, interest income recognized
Loans with an allowance recorded, recorded investment	28	34
Loans with an allowance recorded, unpaid principal balance	28	34
Related allowance	28	34
Loans with an allowance recorded, average recorded investment	1,851	1,882
Loans with an allowance recorded, interest income recognized	2	78
Recorded investment	220	1,176
Unpaid principal balance	735	2,236
Average recorded investment	2,012	2,293
Interest income recognized	2	78
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans with no related allowance recorded, recorded investment	318	664
Loans with no related allowance recorded, unpaid principal balance	489	834
Loans with no related allowance recorded, average recorded investment	437	559
Loans with no related allowance recorded, interest income recognized
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
Loans with an allowance recorded, interest income recognized
Recorded investment	318	664
Unpaid principal balance	489	834
Average recorded investment	437	559
Interest income recognized
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 no related allowance recorded, interest income recognized
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	24	48
Loans with an allowance recorded, interest income recognized
Recorded investment	474	474
Unpaid principal balance	506	506
Average recorded investment	498	473
Interest income recognized
Real Estate Mortgage Portfolio Segment [Member]
Loans with no related allowance recorded, recorded investment	1,627	5,052
Loans with no related allowance recorded, unpaid principal balance	2,064	5,530
Loans with no related allowance recorded, average recorded investment	2,853	2,909
Loans with no related allowance recorded, interest income recognized
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	911	5
Loans with an allowance recorded, interest income recognized	1
Recorded investment	1,641	5,066
Unpaid principal balance	2,078	5,544
Average recorded investment	3,764	2,914
Interest income recognized	1
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans with no related allowance recorded, recorded investment	138	52
Loans with no related allowance recorded, unpaid principal balance	138	53
Loans with no related allowance recorded, average recorded investment	35	110
Loans with no related allowance recorded, interest income recognized
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
Loans with an allowance recorded, interest income recognized
Recorded investment	138	52
Unpaid principal balance	138	53
Average recorded investment	35	110
Interest income recognized
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans with no related allowance recorded, recorded investment	586	3,332
Loans with no related allowance recorded, unpaid principal balance	1,023	3,789
Loans with no related allowance recorded, average recorded investment	1,503	1,678
Loans with no related allowance recorded, interest income recognized
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	897
Loans with an allowance recorded, interest income recognized
Recorded investment	586	3,332
Unpaid principal balance	1,023	3,789
Average recorded investment	2,400	1,678
Interest income recognized
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans with no related allowance recorded, recorded investment	760	1,637
Loans with no related allowance recorded, unpaid principal balance	760	1,657
Loans with no related allowance recorded, average recorded investment	1,242	935
Loans with no related allowance recorded, interest income recognized
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
Loans with an allowance recorded, interest income recognized	1
Recorded investment	774	1,651
Unpaid principal balance	774	1,671
Average recorded investment	1,256	940
Interest income recognized	1
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 no related allowance recorded, interest income recognized
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
Loans with an allowance recorded, interest income recognized
Recorded investment
Unpaid principal balance
Average recorded investment
Interest income recognized
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans with no related allowance recorded, recorded investment	143	31
Loans with no related allowance recorded, unpaid principal balance	143	31
Loans with no related allowance recorded, average recorded investment	73	186
Loans with no related allowance recorded, interest income recognized
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
Loans with an allowance recorded, interest income recognized
Recorded investment	143	31
Unpaid principal balance	143	31
Average recorded investment	73	186
Interest income recognized
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	23
Loans with no related allowance recorded, interest income recognized
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
Loans with an allowance recorded, interest income recognized
Recorded investment
Unpaid principal balance
Average recorded investment	23	46
Interest income recognized