Note 10 - Fair Value of Financial Instruments - Quantitative Information About Non-recurring Level 3 Fair Value of Financial Instruments and the Fair Value Measurements (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Assets	$ 14,958	$ 15,501
Fair Value	14,958	15,501
Impaired Loans [Member]
Assets	14,958	14,968
Fair Value	14,958	14,968
Impaired Loans [Member] | Income Approach Valuation Technique [Member]
Assets	2,014	$ 2,007
Range, loss severity discount		15.00%
Fair Value	$ 2,014	$ 2,007
Impaired Loans [Member] | Income Approach Valuation Technique [Member] | Minimum [Member]
Range, capitalization rate	6.00%	6.00%
Range, loss severity discount	10.90%
Impaired Loans [Member] | Income Approach Valuation Technique [Member] | Maximum [Member]
Range, capitalization rate	7.50%	7.50%
Range, loss severity discount	15.00%
Impaired Loans [Member] | Income Approach Valuation Technique [Member] | Weighted Average [Member]
Range, capitalization rate	7.00%	7.00%
Range, loss severity discount	14.20%	15.00%
Impaired Loans [Member] | Sales Approach Valuation Technique [Member]
Assets	$ 8,984	$ 8,703
Fair Value	$ 8,984	$ 8,703
Impaired Loans [Member] | Sales Approach Valuation Technique [Member] | Minimum [Member]
Range, loss severity discount		0.00%
Range, comparability adjustments	(40.00%)	(40.00%)
Impaired Loans [Member] | Sales Approach Valuation Technique [Member] | Maximum [Member]
Range, loss severity discount		15.00%
Range, comparability adjustments	16.20%	16.20%
Impaired Loans [Member] | Sales Approach Valuation Technique [Member] | Weighted Average [Member]
Range, loss severity discount	8.00%	7.70%
Range, comparability adjustments	1.50%	1.50%
Impaired Loans [Member] | Blended Income and Sales Approach [Member]
Assets	$ 3,960	$ 4,258
Range, loss severity discount		15.00%
Fair Value	$ 3,960	$ 4,258
Impaired Loans [Member] | Blended Income and Sales Approach [Member] | Minimum [Member]
Range, capitalization rate	5.30%	5.30%
Range, loss severity discount	14.50%
Range, comparability adjustments	(29.00%)	(50.00%)
Impaired Loans [Member] | Blended Income and Sales Approach [Member] | Maximum [Member]
Range, capitalization rate	9.50%	9.50%
Range, loss severity discount	15.00%
Range, comparability adjustments	25.00%	25.00%
Impaired Loans [Member] | Blended Income and Sales Approach [Member] | Weighted Average [Member]
Range, capitalization rate	7.10%	7.20%
Range, loss severity discount	15.00%	15.00%
Range, comparability adjustments	0.00%	0.60%
Other Real Estate Owned [Member]
Assets		$ 533
Fair Value		533
Other Real Estate Owned [Member] | Blended Income and Sales Approach [Member]
Assets		533
Fair Value		$ 533
Other Real Estate Owned [Member] | Blended Income and Sales Approach [Member] | Minimum [Member]
Range, comparability adjustments		3.30%
Other Real Estate Owned [Member] | Blended Income and Sales Approach [Member] | Maximum [Member]
Range, comparability adjustments		18.60%
Other Real Estate Owned [Member] | Blended Income and Sales Approach [Member] | Weighted Average [Member]
Range, comparability adjustments		11.00%