Note 11 - Fair Value of Financial Instruments and Fair Value Measurements - Quantitative Information for Financial Instruments Measured at Fair Value (Details) - Fair Value, Inputs, Level 3 [Member] - Fair Value, Measurements, Nonrecurring [Member] - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Commercial Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Commercial Construction [Member]
Assets measured at fair value	$ 428
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Commercial Construction [Member]
Assets measured at fair value		$ 51
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Commercial Construction [Member] | Minimum [Member]
Fair value inputs, comparability adjustments	(16.00%)	(5.00%)
Fair value inputs, management adjustments	0.00%	0.00%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Commercial Construction [Member] | Maximum [Member]
Fair value inputs, comparability adjustments	1975.00%	99.00%
Fair value inputs, management adjustments	10.00%	10.00%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Commercial Construction [Member] | Weighted Average [Member]
Fair value inputs, comparability adjustments	979.50%	47.00%
Fair value inputs, management adjustments	5.00%	5.00%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Residential [Member]
Assets measured at fair value	$ 16	$ 1,105
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Residential [Member] | Minimum [Member]
Fair value inputs, comparability adjustments	(43.30%)	(22.00%)
Fair value inputs, management adjustments	10.00%	0.00%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Residential [Member] | Maximum [Member]
Fair value inputs, comparability adjustments	83.30%	0.00%
Fair value inputs, management adjustments	25.00%	40.00%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Residential [Member] | Weighted Average [Member]
Fair value inputs, comparability adjustments	20.00%	(11.00%)
Fair value inputs, management adjustments	17.50%	20.00%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Commercial [Member]
Assets measured at fair value	$ 5,653	$ 5,445
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Commercial [Member] | Minimum [Member]
Fair value inputs, comparability adjustments		(14.08%)
Fair value inputs, management adjustments	0.00%	0.00%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Commercial [Member] | Maximum [Member]
Fair value inputs, comparability adjustments		24.62%
Fair value inputs, management adjustments	10.00%	100.00%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Commercial [Member] | Weighted Average [Member]
Fair value inputs, comparability adjustments		5.27%
Fair value inputs, management adjustments	5.00%	50.00%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Farmland [Member]
Assets measured at fair value	$ 349	$ 351
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Farmland [Member] | Minimum [Member]
Fair value inputs, comparability adjustments	(71.00%)	(27.00%)
Fair value inputs, management adjustments	10.00%	10.00%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Farmland [Member] | Maximum [Member]
Fair value inputs, comparability adjustments	88.70%	15.00%
Fair value inputs, management adjustments	75.00%	75.00%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Farmland [Member] | Weighted Average [Member]
Fair value inputs, comparability adjustments	8.85%	(6.00%)
Fair value inputs, management adjustments	42.50%	42.50%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Other Real Estate Owned [Member]
Assets measured at fair value	$ 1,625	$ 2,505
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Other Real Estate Owned [Member] | Minimum [Member]
Fair value inputs, comparability adjustments	(34.01%)	(50.80%)
Fair value inputs, management adjustments	1.60%	6.25%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Other Real Estate Owned [Member] | Maximum [Member]
Fair value inputs, comparability adjustments	35.00%	316.00%
Fair value inputs, management adjustments	81.32%	76.92%
Real Estate Portfolio Segment [Member] | Market Approach Valuation Technique [Member] | Other Real Estate Owned [Member] | Weighted Average [Member]
Fair value inputs, comparability adjustments	0.50%	132.60%
Fair value inputs, management adjustments	29.15%	36.31%
Real Estate Portfolio Segment [Member] | Income Approach Valuation Technique [Member] | Commercial [Member] | Weighted Average [Member]
Fair value inputs, management adjustments		10.67%
Fair value inputs, capitalization rate	10.67%
Real Estate Portfolio Segment [Member] | Income Approach Valuation Technique [Member] | Other Real Estate Owned [Member] | Weighted Average [Member]
Range Weighted Average		12.50%