Note 5 - Retail Loans by Credit Quality (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	$ 632,999	$ 615,263
Total Retail Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	124,319	114,503
Performing Financial Instruments [Member] | Total Retail Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	123,871	114,089
Nonperforming Financial Instruments [Member] | Total Retail Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	448	414
Retail Portfolio Segment [Member] | Consumer Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	5,670	4,286
Retail Portfolio Segment [Member] | Family Residential Mortgages [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	47,124	42,833
Retail Portfolio Segment [Member] | Home Equity Loans and Lines [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	71,525	67,384
Retail Portfolio Segment [Member] | Performing Financial Instruments [Member] | Consumer Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	5,577	4,286
Retail Portfolio Segment [Member] | Performing Financial Instruments [Member] | Family Residential Mortgages [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	46,858	42,546
Retail Portfolio Segment [Member] | Performing Financial Instruments [Member] | Home Equity Loans and Lines [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	71,436	67,257
Retail Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Consumer Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	93	0
Retail Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Family Residential Mortgages [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	266	287
Retail Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Home Equity Loans and Lines [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	$ 89	$ 127