Note 8 - Loans and Related Allowance for Loan and Lease Losses - Allowance for Loan Losses (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Dec. 31, 2018
Individually evaluated for impairment			$ 963,000	$ 1,354,000
Collectively evaluated for impairment			6,243,000	6,074,000
Total ending allowance balance	$ 7,206,000	$ 7,190,000	7,206,000	7,428,000
ALLL balance, period start	7,428,000	7,190,000
Charge-offs	(517,000)	(13,000)
Recoveries	55,000	164,000
Provision	240,000	210,000
ALLL balance, period end	7,206,000	7,551,000
Commercial And Industrial [Member]
Individually evaluated for impairment			203,000	667,000
Collectively evaluated for impairment			383,000	302,000
Total ending allowance balance	586,000	999,000	586,000	969,000
ALLL balance, period start	969,000	999,000
Charge-offs	(347,000)	(9,000)
Recoveries	16,000	109,000
Provision	(52,000)	157,000
ALLL balance, period end	586,000	1,256,000
Real Estate Construction Porfolio Segment [Member]
Individually evaluated for impairment			661,000
Collectively evaluated for impairment			87,000	100,000
Total ending allowance balance	748,000	313,000	748,000	100,000
ALLL balance, period start	100,000	313,000
Charge-offs	0
Recoveries	23,000	17,000
Provision	625,000	(238,000)
ALLL balance, period end	748,000	92,000
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Individually evaluated for impairment			45,000	43,000
Collectively evaluated for impairment			1,578,000	1,538,000
Total ending allowance balance	1,623,000	1,760,000	1,623,000	1,581,000
ALLL balance, period start	1,581,000	1,760,000
Charge-offs	(91,000)
Recoveries	14,000	20,000
Provision	119,000	2,000
ALLL balance, period end	1,623,000	1,782,000
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Individually evaluated for impairment			54,000	643,000
Collectively evaluated for impairment			4,107,000	4,008,000
Total ending allowance balance	4,161,000	4,036,000	4,161,000	4,651,000
ALLL balance, period start	4,651,000	4,036,000
Charge-offs	(32,000)
Recoveries	1,000
Provision	(459,000)	287,000
ALLL balance, period end	4,161,000	4,323,000
Consumer Portfolio Segment [Member]
Individually evaluated for impairment				1,000
Collectively evaluated for impairment			88,000	126,000
Total ending allowance balance	88,000	82,000	$ 88,000	$ 127,000
ALLL balance, period start	127,000	82,000
Charge-offs	(47,000)	(4,000)
Recoveries	1,000	18,000
Provision	7,000	2,000
ALLL balance, period end	$ 88,000	$ 98,000