Note 4 - Loans and Allowance for Loan Losses - Loans Individually Evaluated for Impairment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Unpaid principal balance - with allowance recorded
Recorded investment - with allowance recorded
Allowance for Loan Losses Allocated					$ 98
Unpaid principal balance	20,066		20,066		14,376
Recorded investment	17,245		17,245		12,618
Average impaired loans - with allowance recorded
With an allowance Interest income recognized - with allowance recorded
Cash basis interest recognized - with allowance recorded
Average impaired loans	18,014	$ 11,264	16,058	$ 11,391
Interest income recognized	329	148	939	534
Cash basis interest recognized	329	148	939	534
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Unpaid principal balance - with allowance recorded	9,421		9,421		362
Recorded investment - with allowance recorded	8,098		8,098		362
Allowance for Loan Losses Allocated					98
Unpaid principal balance - with no allowance recorded					2,368
Recorded investment - with no allowance recorded					946
Average impaired loans - with allowance recorded	7,949	365	6,243	368
With an allowance Interest income recognized - with allowance recorded	142	3	370	12
Cash basis interest recognized - with allowance recorded	142	3	370	12
Average impaired loans - with no allowance recorded		1,786		2,154
Interest income recognized - with no allowance recorded		11		47
Cash basis interest recognized - with no allowance recorded		11		47
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Allowance for Loan Losses Allocated
Unpaid principal balance - with no allowance recorded	3,244		3,244		2,527
Recorded investment - with no allowance recorded	3,244		3,244		2,527
Average impaired loans - with no allowance recorded	3,349	2,434	3,144	2,462
Interest income recognized - with no allowance recorded	53	36	167	105
Cash basis interest recognized - with no allowance recorded	53	36	167	105
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Allowance for Loan Losses Allocated
Unpaid principal balance - with no allowance recorded	323		323		336
Recorded investment - with no allowance recorded
Average impaired loans - with no allowance recorded
Interest income recognized - with no allowance recorded	5	5	15	15
Cash basis interest recognized - with no allowance recorded	5	5	15	15
Residential Portfolio Segment [Member]
Unpaid principal balance - with allowance recorded					1,667
Recorded investment - with allowance recorded					1,667
Allowance for Loan Losses Allocated
Unpaid principal balance - with no allowance recorded	445		445
Recorded investment - with no allowance recorded	445		445
Average impaired loans - with allowance recorded		707		711
With an allowance Interest income recognized - with allowance recorded
Cash basis interest recognized - with allowance recorded
Average impaired loans - with no allowance recorded	446	219	469	222
Interest income recognized - with no allowance recorded	4	4	20	34
Cash basis interest recognized - with no allowance recorded	4	4	20	34
Commercial and Industrial Portfolio Segment [Member]
Allowance for Loan Losses Allocated
Unpaid principal balance - with no allowance recorded	6,277		6,277		7,116
Recorded investment - with no allowance recorded	5,102		5,102		$ 7,116
Average impaired loans - with no allowance recorded	6,089	5,753	6,110	5,474
Interest income recognized - with no allowance recorded	110	89	352	321
Cash basis interest recognized - with no allowance recorded	110	$ 89	352	$ 321
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Allowance for Loan Losses Allocated
Unpaid principal balance - with no allowance recorded	350		350
Average impaired loans - with no allowance recorded	175		87
Interest income recognized - with no allowance recorded	15		15
Cash basis interest recognized - with no allowance recorded	15		15
Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Allowance for Loan Losses Allocated
Unpaid principal balance - with no allowance recorded	6		6
Recorded investment - with no allowance recorded	6		6
Average impaired loans - with no allowance recorded	6		5
Interest income recognized - with no allowance recorded
Cash basis interest recognized - with no allowance recorded