Note 8 - Loans and Related Allowance for Loan and Lease Losses - Allowance for Loan Losses (Details) - USD ($)	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Dec. 31, 2017
Individually evaluated for impairment			$ 1,877,000	$ 1,567,000
Collectively evaluated for impairment			5,674,000	5,623,000
Total ending allowance balance	$ 7,551,000	$ 6,598,000	7,551,000	7,190,000
ALLL balance, period start	7,190,000	6,598,000
Charge-offs	(13,000)	(208,000)
Recoveries	164,000	165,000
Provision for Loan, Lease, and Other Losses, Total	210,000	165,000
ALLL balance, period end	7,551,000	6,720,000
Commercial And Industrial [Member]
Individually evaluated for impairment			997,000	694,000
Collectively evaluated for impairment			259,000	305,000
Total ending allowance balance	1,256,000	448,000	1,256,000	999,000
ALLL balance, period start	999,000	448,000
Charge-offs	(9,000)	(20,000)
Recoveries	109,000	78,000
Provision for Loan, Lease, and Other Losses, Total	157,000	110,000
ALLL balance, period end	1,256,000	616,000
Real Estate Construction Porfolio Segment [Member]
Individually evaluated for impairment
Collectively evaluated for impairment			92,000	313,000
Total ending allowance balance	92,000	172,000	92,000	313,000
ALLL balance, period start	313,000	172,000
Charge-offs
Recoveries	17,000	17,000
Provision for Loan, Lease, and Other Losses, Total	(238,000)	(3,000)
ALLL balance, period end	92,000	186,000
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member]
Individually evaluated for impairment			124,000	140,000
Collectively evaluated for impairment			1,658,000	1,620,000
Total ending allowance balance	1,782,000	2,818,000	1,782,000	1,760,000
ALLL balance, period start	1,760,000	2,818,000
Charge-offs		(68,000)
Recoveries	20,000	7,000
Provision for Loan, Lease, and Other Losses, Total	2,000	(234,000)
ALLL balance, period end	1,782,000	2,523,000
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Loans [Member]
Individually evaluated for impairment			756,000	733,000
Collectively evaluated for impairment			3,567,000	3,303,000
Total ending allowance balance	4,323,000	3,135,000	4,323,000	4,036,000
ALLL balance, period start	4,036,000	3,135,000
Charge-offs		(19,000)
Recoveries
Provision for Loan, Lease, and Other Losses, Total	287,000	262,000
ALLL balance, period end	4,323,000	3,378,000
Consumer Portfolio Segment [Member]
Individually evaluated for impairment
Collectively evaluated for impairment			98,000	82,000
Total ending allowance balance	98,000	25,000	$ 98,000	$ 82,000
ALLL balance, period start	82,000	25,000
Charge-offs	(4,000)	(101,000)
Recoveries	18,000	63,000
Provision for Loan, Lease, and Other Losses, Total	2,000	30,000
ALLL balance, period end	$ 98,000	$ 17,000

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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