Note 3 - Loans - Summary of Changes in Allowance for Loan Losses (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
Beginning balance	$ 4,006	$ 3,541	$ 3,661	$ 3,136
Provision (credit) for loan losses	241	135	585	544
Net (charge-offs) recoveries	(265)	(2)	(264)	(6)
Recorded investment, individually evaluated for impairment	3,252		3,252		$ 1,231
Balance in allowance for loan losses, individually evaluated for impairment	255		255		211
Recorded investment, collectively evaluated for impairment	316,009		316,009		292,083
Balance in allowance for loan losses, collectively evaluated for impairment	3,727		3,727		3,450
Mortgage Receivable [Member] \| Commercial Real Estate Portfolio Segment [Member]
Beginning balance	813	1,001	917	894
Provision (credit) for loan losses	48	(61)	(56)	46
Net (charge-offs) recoveries
Recorded investment, individually evaluated for impairment	611		611		611
Balance in allowance for loan losses, individually evaluated for impairment
Recorded investment, collectively evaluated for impairment	77,413		77,413		81,883
Balance in allowance for loan losses, collectively evaluated for impairment	861		861		917
Mortgage Receivable [Member] \| Residential Portfolio Segment [Member]
Beginning balance	1,458	1,309	1,397	1,097
Provision (credit) for loan losses	17	79	78	291
Net (charge-offs) recoveries
Recorded investment, individually evaluated for impairment	1,133		1,133		409
Balance in allowance for loan losses, individually evaluated for impairment
Recorded investment, collectively evaluated for impairment	127,785		127,785		121,045
Balance in allowance for loan losses, collectively evaluated for impairment	1,475		1,475		1,397
Mortgage Receivable [Member] \| Real Estate Construction Loan [Member]
Beginning balance	425	400	391	331
Provision (credit) for loan losses	76	(12)	110	57
Net (charge-offs) recoveries		(3)		(3)
Recorded investment, individually evaluated for impairment
Balance in allowance for loan losses, individually evaluated for impairment
Recorded investment, collectively evaluated for impairment	41,149		41,149		31,601
Balance in allowance for loan losses, collectively evaluated for impairment	501		501		391
Loans and Finance Receivables [Member] \| Commercial Portfolio Segment [Member]
Beginning balance	1,225	749	876	724
Provision (credit) for loan losses	76	126	423	148
Net (charge-offs) recoveries	(260)	1	(258)	4
Recorded investment, individually evaluated for impairment	1,482		1,482		205
Balance in allowance for loan losses, individually evaluated for impairment	229		229		205
Recorded investment, collectively evaluated for impairment	61,989		61,989		50,813
Balance in allowance for loan losses, collectively evaluated for impairment	812		812		671
Loans and Finance Receivables [Member] \| Consumer Portfolio Segment [Member]
Beginning balance	85	82	80	90
Provision (credit) for loan losses	24	3	30	2
Net (charge-offs) recoveries	(5)		(6)	$ (7)
Recorded investment, individually evaluated for impairment	26		26		6
Balance in allowance for loan losses, individually evaluated for impairment	26		26		6
Recorded investment, collectively evaluated for impairment	7,673		7,673		6,741
Balance in allowance for loan losses, collectively evaluated for impairment	$ 78		$ 78		$ 74

Amount, after recoveries, of loans and leases that have been written-off.

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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 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 to estimated loss from loan and lease transactions.

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