Note 4 - Loans and the Allowance for Loan Losses (Details Textual)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Residential Portfolio Segment [Member]
Real Estate Acquired Through Foreclosure	$ 0		$ 0		$ 84,000
Impaired Financing Receivable, Interest Income, Cash Basis Method			0	$ 0
Loans and Leases Receivable, Impaired, Commitment to Lend	0		$ 0		0
Financing Receivable, Modifications, Number of Contracts			0	0
Financing Receivable, Modifications, Subsequent Default, Number of Contracts			0	0
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0		$ 0		0
Impaired Financing Receivable, Recorded Investment	5,832,000		5,832,000		6,461,000
Impaired Financing Receivable, Related Allowance	480,000		480,000		751,000
Impaired Financing Receivable, with Related Allowance, Recorded Investment	1,678,000		1,678,000		2,346,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	4,153,000		4,153,000		4,115,000
Impaired Financing Receivable, Average Recorded Investment			5,398,000	$ 6,892,000	6,528,000
Impaired Financing Receivable, Interest Income, Accrual Method			105,000	89,000	119,000
Financing Receivable, Modifications, Recorded Investment	4,739,000		4,739,000		4,661,000
Financing Receivable Modifications Related Allowances	386,000		386,000		311,000
Financing Receivable, Recorded Investment, Nonaccrual Status	3,100,000		3,100,000		4,546,000
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans	51,000	$ 66,000	157,000	270,000
Deferred Loan Origination Costs	495,000	$ 319,000	1,437,000	$ 1,035,000
Threshold Limit for Loans to Be Reviewed for Credit Risk			100,000
Mortgage Loans in Process of Foreclosure, Amount	$ 243,000		$ 243,000		$ 23,000