Note 9 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value On a Non-recurring Basis (Details) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Gain (Loss) on Sale of Assets and Asset Impairment Charges	$ (23,000)		$ (89,000)
Assets Fair Value Disclosure Nonrecurring	1,396,000		1,271,000
Fair Value, Inputs, Level 3 [Member]
Assets Fair Value Disclosure Nonrecurring	1,396,000		1,271,000
Impaired Loans [Member]
Gain (Loss) on Sale of Assets and Asset Impairment Charges	(14,000)	$ (80,000)	(80,000)
Assets Fair Value Disclosure Nonrecurring	552,000		536,000
Impaired Loans [Member] | Fair Value, Inputs, Level 3 [Member]
Assets Fair Value Disclosure Nonrecurring	552,000		536,000
Other Real Estate [Member]
Gain (Loss) on Sale of Assets and Asset Impairment Charges	(9,000)		(9,000)
Assets Fair Value Disclosure Nonrecurring	844,000		735,000
Other Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Assets Fair Value Disclosure Nonrecurring	844,000		735,000
Commercial Portfolio Segment [Member] | Real Estate Loan [Member] | Impaired Loans [Member]
Gain (Loss) on Sale of Assets and Asset Impairment Charges	5,000		(81,000)
Assets Fair Value Disclosure Nonrecurring	450,000		453,000
Commercial Portfolio Segment [Member] | Real Estate Loan [Member] | Impaired Loans [Member] | Fair Value, Inputs, Level 3 [Member]
Assets Fair Value Disclosure Nonrecurring	450,000		453,000
Commercial Portfolio Segment [Member] | Real Estate Loan [Member] | Other Real Estate [Member]
Gain (Loss) on Sale of Assets and Asset Impairment Charges	(9,000)		(9,000)
Assets Fair Value Disclosure Nonrecurring	193,000		84,000
Commercial Portfolio Segment [Member] | Real Estate Loan [Member] | Other Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Assets Fair Value Disclosure Nonrecurring	193,000		84,000
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Impaired Loans [Member]
Assets Fair Value Disclosure Nonrecurring	641,000		641,000
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Other Real Estate [Member]
Assets Fair Value Disclosure Nonrecurring	641,000		641,000
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Other Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Assets Fair Value Disclosure Nonrecurring	641,000		641,000
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Other Real Estate [Member]
Assets Fair Value Disclosure Nonrecurring	10,000		10,000
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Other Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Assets Fair Value Disclosure Nonrecurring	10,000		10,000
Residential Portfolio Segment [Member] | Equity Lines of Credit [Member] | Impaired Loans [Member]
Gain (Loss) on Sale of Assets and Asset Impairment Charges	(19,000)		1,000
Assets Fair Value Disclosure Nonrecurring	102,000		83,000
Residential Portfolio Segment [Member] | Equity Lines of Credit [Member] | Impaired Loans [Member] | Fair Value, Inputs, Level 3 [Member]
Assets Fair Value Disclosure Nonrecurring	$ 102,000		$ 83,000