Note 5 - Loans Receivable and Related Allowance for Loan Losses - Classes of Loan Portfolio by Aging Categories (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accruing loans not past due	$ 588,285	$ 574,298
Nonaccrual	4,953	3,003
Loans	598,485	583,361
Financing Receivables, 30 to 59 Days Past Due [Member]
Accruing loans past due	4,081	3,907
Nonaccrual
Financing Receivables, 60 to 89 Days Past Due [Member]
Accruing loans past due	631	1,463
Nonaccrual	342	75
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Accruing loans past due	535	690
Nonaccrual	1,554	1,644
Residential Portfolio Segment [Member]
Accruing loans not past due	233,448	218,515
Nonaccrual	1,083	856
Loans	237,106	221,823
Residential Portfolio Segment [Member] \| Financing Receivables, 30 to 59 Days Past Due [Member]
Accruing loans past due	2,019	1,936
Nonaccrual
Residential Portfolio Segment [Member] \| Financing Receivables, 60 to 89 Days Past Due [Member]
Accruing loans past due	427	357
Nonaccrual	74	75
Residential Portfolio Segment [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Accruing loans past due	129	159
Nonaccrual	663	415
Home Equity Loans and Lines of Credit [Member]
Accruing loans not past due	97,716	98,112
Nonaccrual	521	526
Loans	99,668	99,940
Home Equity Loans and Lines of Credit [Member] \| Financing Receivables, 30 to 59 Days Past Due [Member]
Accruing loans past due	906	598
Nonaccrual
Home Equity Loans and Lines of Credit [Member] \| Financing Receivables, 60 to 89 Days Past Due [Member]
Accruing loans past due	146	370
Nonaccrual
Home Equity Loans and Lines of Credit [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Accruing loans past due	379	334
Nonaccrual	514	518
Commercial Real Estate Portfolio Segment [Member]
Accruing loans not past due	196,184	190,451
Nonaccrual	3,240	964
Loans	200,169	193,068
Commercial Real Estate Portfolio Segment [Member] \| Financing Receivables, 30 to 59 Days Past Due [Member]
Accruing loans past due	737	1,026
Nonaccrual
Commercial Real Estate Portfolio Segment [Member] \| Financing Receivables, 60 to 89 Days Past Due [Member]
Accruing loans past due	8	430
Nonaccrual	268
Commercial Real Estate Portfolio Segment [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Accruing loans past due		197
Nonaccrual	307	623
Commercial Portfolio Segment [Member]
Accruing loans not past due	52,233	58,058
Nonaccrual	39	584
Loans	52,594	58,941
Commercial Portfolio Segment [Member] \| Financing Receivables, 30 to 59 Days Past Due [Member]
Accruing loans past due	322	74
Nonaccrual
Commercial Portfolio Segment [Member] \| Financing Receivables, 60 to 89 Days Past Due [Member]
Accruing loans past due		225
Nonaccrual
Commercial Portfolio Segment [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Accruing loans past due
Nonaccrual		15
Consumer Portfolio Segment [Member]
Accruing loans not past due	8,704	9,162
Nonaccrual	70	73
Loans	8,948	9,589
Consumer Portfolio Segment [Member] \| Financing Receivables, 30 to 59 Days Past Due [Member]
Accruing loans past due	97	273
Nonaccrual
Consumer Portfolio Segment [Member] \| Financing Receivables, 60 to 89 Days Past Due [Member]
Accruing loans past due	50	81
Nonaccrual
Consumer Portfolio Segment [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Accruing loans past due	27
Nonaccrual	$ 70	$ 73

Financing receivables that are current.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953401-111524

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Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-SubTopic 10
-Section 45
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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