Note 4 - Loans Receivable and Allowance for Loan Losses - Delinquency Status of Performing and Non-performing Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Loans receivable, gross	$ 724,555	$ 719,647
Non-accruing loans	5,036	3,778
Commercial Real Estate Portfolio Segment [Member]
Loans receivable, gross	313,868	299,925
Non-accruing loans	474
Residential Portfolio Segment [Member]
Loans receivable, gross	144,633	146,377
Non-accruing loans	3,037	3,028
Commercial Portfolio Segment [Member]
Loans receivable, gross	129,913	131,161
Non-accruing loans	1,521	748
Consumer Portfolio Segment [Member]
Loans receivable, gross	83,185	87,707
Non-accruing loans	4	2
Construction Portfolio Segment [Member]
Loans receivable, gross	46,348	47,619
Non-accruing loans
Construction to Permanent Portfolio Segment [Member]
Loans receivable, gross	6,608	6,858
Pass [Member]
Loans receivable, gross	695,506	699,862
Non-accruing loans
Pass [Member] \| Commercial Real Estate Portfolio Segment [Member]
Loans receivable, gross	299,700	286,428
Non-accruing loans
Pass [Member] \| Residential Portfolio Segment [Member]
Loans receivable, gross	140,077	141,820
Non-accruing loans
Pass [Member] \| Commercial Portfolio Segment [Member]
Loans receivable, gross	128,392	129,432
Non-accruing loans
Pass [Member] \| Consumer Portfolio Segment [Member]
Loans receivable, gross	83,181	87,705
Non-accruing loans
Pass [Member] \| Construction Portfolio Segment [Member]
Loans receivable, gross	37,548	47,619
Non-accruing loans
Pass [Member] \| Construction to Permanent Portfolio Segment [Member]
Loans receivable, gross	6,608	6,858
Non-accruing loans
Special Mention [Member]
Loans receivable, gross	11,508	11,967
Non-accruing loans
Special Mention [Member] \| Commercial Real Estate Portfolio Segment [Member]
Loans receivable, gross	9,989	10,438
Non-accruing loans
Special Mention [Member] \| Residential Portfolio Segment [Member]
Loans receivable, gross	1,519	1,529
Non-accruing loans
Special Mention [Member] \| Commercial Portfolio Segment [Member]
Loans receivable, gross
Non-accruing loans
Substandard [Member]
Loans receivable, gross	17,541	7,818
Non-accruing loans	5,036	3,778
Substandard [Member] \| Commercial Real Estate Portfolio Segment [Member]
Loans receivable, gross	4,179	3,059
Non-accruing loans	474
Substandard [Member] \| Residential Portfolio Segment [Member]
Loans receivable, gross	3,037	3,028
Non-accruing loans	3,037	3,028
Substandard [Member] \| Commercial Portfolio Segment [Member]
Loans receivable, gross	1,521	1,729
Non-accruing loans	1,521	748
Substandard [Member] \| Consumer Portfolio Segment [Member]
Loans receivable, gross	4	2
Non-accruing loans	4	2
Substandard [Member] \| Construction Portfolio Segment [Member]
Loans receivable, gross	8,800
Non-accruing loans
Performing Financial Instruments [Member]
Performing (accruing) loans, past due	18,825	9,515
Performing (accruing) loans, current	700,694	706,354
Loans receivable, gross	719,519	715,869
Performing Financial Instruments [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due	3,394	2,809
Performing (accruing) loans, current	310,000	297,116
Loans receivable, gross	313,394	299,925
Performing Financial Instruments [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due	2,911	2,852
Performing (accruing) loans, current	138,685	140,497
Loans receivable, gross	141,596	143,349
Performing Financial Instruments [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due	1,122	3,356
Performing (accruing) loans, current	127,270	127,057
Loans receivable, gross	128,392	130,413
Performing Financial Instruments [Member] \| Consumer Portfolio Segment [Member]
Performing (accruing) loans, past due	559	498
Performing (accruing) loans, current	82,622	87,207
Loans receivable, gross	83,181	87,705
Performing Financial Instruments [Member] \| Construction Portfolio Segment [Member]
Performing (accruing) loans, past due	10,839
Performing (accruing) loans, current	35,509
Loans receivable, gross	46,348
Performing Financial Instruments [Member] \| Pass [Member]
Performing (accruing) loans, past due	5,801	4,196
Performing (accruing) loans, current	689,705	695,666
Loans receivable, gross	695,506	699,862
Performing Financial Instruments [Member] \| Pass [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due	689
Performing (accruing) loans, current	299,011	286,428
Loans receivable, gross	299,700	286,428
Performing Financial Instruments [Member] \| Pass [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due	1,392	1,323
Performing (accruing) loans, current	138,685	140,497
Loans receivable, gross	140,077	141,820
Performing Financial Instruments [Member] \| Pass [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due	1,122	2,375
Performing (accruing) loans, current	127,270	127,057
Loans receivable, gross	128,392	129,432
Performing Financial Instruments [Member] \| Pass [Member] \| Consumer Portfolio Segment [Member]
Performing (accruing) loans, past due	559	498
Performing (accruing) loans, current	82,622	87,207
Loans receivable, gross	83,181	87,705
Performing Financial Instruments [Member] \| Pass [Member] \| Construction Portfolio Segment [Member]
Performing (accruing) loans, past due	2,039
Performing (accruing) loans, current	35,509	47,619
Loans receivable, gross	37,548	47,619
Performing Financial Instruments [Member] \| Pass [Member] \| Construction to Permanent Portfolio Segment [Member]
Performing (accruing) loans, past due
Performing (accruing) loans, current	6,608	6,858
Loans receivable, gross	6,608	6,858
Performing Financial Instruments [Member] \| Special Mention [Member]
Performing (accruing) loans, past due	1,519	2,650
Performing (accruing) loans, current	9,989	9,317
Loans receivable, gross	11,508	11,967
Performing Financial Instruments [Member] \| Special Mention [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due		1,121
Performing (accruing) loans, current	9,989	9,317
Loans receivable, gross	9,989	10,438
Performing Financial Instruments [Member] \| Special Mention [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due	1,519	1,529
Performing (accruing) loans, current
Loans receivable, gross	1,519	1,529
Performing Financial Instruments [Member] \| Special Mention [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due
Performing (accruing) loans, current
Loans receivable, gross
Performing Financial Instruments [Member] \| Substandard [Member]
Performing (accruing) loans, past due	11,505	2,669
Performing (accruing) loans, current	1,000	1,371
Loans receivable, gross	12,505	4,040
Performing Financial Instruments [Member] \| Substandard [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due	2,705	1,688
Performing (accruing) loans, current	1,000	1,371
Loans receivable, gross	3,705	3,059
Performing Financial Instruments [Member] \| Substandard [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due
Performing (accruing) loans, current
Loans receivable, gross
Performing Financial Instruments [Member] \| Substandard [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due		981
Performing (accruing) loans, current
Loans receivable, gross		981
Performing Financial Instruments [Member] \| Substandard [Member] \| Consumer Portfolio Segment [Member]
Performing (accruing) loans, past due
Performing (accruing) loans, current
Loans receivable, gross
Performing Financial Instruments [Member] \| Substandard [Member] \| Construction Portfolio Segment [Member]
Performing (accruing) loans, past due	8,800
Performing (accruing) loans, current
Loans receivable, gross	8,800
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member]
Performing (accruing) loans, past due	2,081	1,566
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due	19
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due	1,640	1,068
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due	293
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Consumer Portfolio Segment [Member]
Performing (accruing) loans, past due	129	498
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Construction Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member]
Performing (accruing) loans, past due	562	1,566
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due	19
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due	121	1,068
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due	293
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Consumer Portfolio Segment [Member]
Performing (accruing) loans, past due	129	498
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Construction Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Construction to Permanent Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Special Mention [Member]
Performing (accruing) loans, past due	1,519
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Special Mention [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Special Mention [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due	1,519
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Special Mention [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member]
Performing (accruing) loans, past due
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Consumer Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 30 to 59 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Construction Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member]
Performing (accruing) loans, past due	5,555	6,593
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due	3,375	2,809
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due	1,271	1,784
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due	829	2,000
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Consumer Portfolio Segment [Member]
Performing (accruing) loans, past due	80
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Construction Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member]
Performing (accruing) loans, past due	2,850	2,255
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due	670
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due	1,271	255
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due	829	2,000
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Consumer Portfolio Segment [Member]
Performing (accruing) loans, past due	80
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Construction Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Construction to Permanent Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Special Mention [Member]
Performing (accruing) loans, past due		2,650
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Special Mention [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due		1,121
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Special Mention [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due		1,529
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Special Mention [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member]
Performing (accruing) loans, past due	2,705	1,688
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due	2,705	1,688
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Consumer Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Construction Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member]
Performing (accruing) loans, past due	11,189	1,356
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due		1,356
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Consumer Portfolio Segment [Member]
Performing (accruing) loans, past due	350
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Construction Portfolio Segment [Member]
Performing (accruing) loans, past due	10,839
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member]
Performing (accruing) loans, past due	2,389	375
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due		375
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Consumer Portfolio Segment [Member]
Performing (accruing) loans, past due	350
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Construction Portfolio Segment [Member]
Performing (accruing) loans, past due	2,039
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Pass [Member] \| Construction to Permanent Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Special Mention [Member]
Performing (accruing) loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Special Mention [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Special Mention [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Special Mention [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member]
Performing (accruing) loans, past due	8,800	981
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Commercial Real Estate Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Residential Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Commercial Portfolio Segment [Member]
Performing (accruing) loans, past due		981
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Consumer Portfolio Segment [Member]
Performing (accruing) loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Performing Financial Instruments [Member] \| Substandard [Member] \| Construction Portfolio Segment [Member]
Performing (accruing) loans, past due	$ 8,800

Note 4 - Loans Receivable and Allowance for Loan Losses - Delinquency Status of Performing and Non-performing Loans (Details) - USD ($)
$ in Thousands