Note 7 - Fair Value Measurements (Details Textual) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Provision for Loan and Lease Losses	$ 211,000	$ 75,000
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0		$ 0
Impaired Loan [Member]
Provision for Loan and Lease Losses	0	106,000
Foreclosed Real Estate [Member]
SEC Schedule III, Real Estate, Write-down or Reserve, Amount	$ 228,000	$ 83,000
Fair Value, Inputs, Level 3 [Member] | Impaired Loan [Member] | Minimum [Member]
Fair Value Inputs, Estimated Selling Costs	12.00%		33.00%
Fair Value, Inputs, Level 3 [Member] | Impaired Loan [Member] | Maximum [Member]
Fair Value Inputs, Estimated Selling Costs	64.00%		65.00%
Fair Value, Inputs, Level 3 [Member] | Impaired Loan [Member] | Weighted Average [Member]
Fair Value Inputs, Estimated Selling Costs	44.00%		39.00%
Fair Value, Inputs, Level 3 [Member] | Foreclosed Real Estate [Member] | Minimum [Member]
Fair Value Inputs, Estimated Selling Costs	10.00%		10.00%
Fair Value, Inputs, Level 3 [Member] | Foreclosed Real Estate [Member] | Maximum [Member]
Fair Value Inputs, Estimated Selling Costs	75.00%		77.00%
Fair Value, Inputs, Level 3 [Member] | Foreclosed Real Estate [Member] | Weighted Average [Member]
Fair Value Inputs, Estimated Selling Costs	42.00%		38.00%