Note 11 - Fair Value of Financial Instruments and Fair Value Measurements - Quantitative Information for Financial Instruments Measured at Fair Value (Details) $ in Thousands | Sep. 30, 2018USD ($) | Dec. 31, 2017USD ($) | Dec. 31, 2016USD ($) |
Other Real Estate Owned, fair value | $ 2,173 | $ 4,256 | $ 6,439 |
Fair Value, Measurements, Nonrecurring [Member] | | | |
Impaired loans, fair value | 5,185 | 4,876 | |
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | | | |
Impaired loans, fair value | 5,185 | 4,876 | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | | | |
Other Real Estate Owned, fair value | $ 1,468 | $ 2,015 | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Other Real Estate Owned, measurement input | (0.476) | (0.2274) | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Appraised Value [Member] | | | |
Other Real Estate Owned, measurement input | 0.0982 | 0.0544 | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Other Real Estate Owned, measurement input | 0.2502 | 0.15 | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Appraised Value [Member] | | | |
Other Real Estate Owned, measurement input | 0.8121 | 0.8724 | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Other Real Estate Owned, measurement input | (0.1129) | (0.0387) | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Appraised Value [Member] | | | |
Other Real Estate Owned, measurement input | 0.3448 | 0.2444 | |
Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Cap Rate [Member] | | | |
Other Real Estate Owned, measurement input | | 0.1 | |
Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Discount Rate [Member] | | | |
Other Real Estate Owned, measurement input | 0.1 | | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | | | |
Impaired loans, fair value | $ 427 | $ 427 | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | (0.16) | (0.16) | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 0 | 0 | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | 19.75 | 19.75 | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 0.1 | 0.1 | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | 9.795 | 9.795 | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 0.05 | 0.05 | |
Real Estate Portfolio Segment [Member] | Residential [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | | | |
Impaired loans, fair value | $ 15 | $ 82 | |
Real Estate Portfolio Segment [Member] | Residential [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | (0.433) | (0.433) | |
Real Estate Portfolio Segment [Member] | Residential [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 0.1 | 0 | |
Real Estate Portfolio Segment [Member] | Residential [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | 0.667 | 0.833 | |
Real Estate Portfolio Segment [Member] | Residential [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 0.25 | 0.25 | |
Real Estate Portfolio Segment [Member] | Residential [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | 0.117 | 0.2 | |
Real Estate Portfolio Segment [Member] | Residential [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 0.175 | 0.125 | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 0 | | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Cost to Sell [Member] | | | |
Impaired loans, measurement input | 0 | | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 10 | | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Cost to Sell [Member] | | | |
Impaired loans, measurement input | 0 | | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | 0.0474 | | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | | | |
Impaired loans, fair value | $ 4,406 | $ 4,017 | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | | 0 | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | | 0.1 | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | | 0.05 | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Cap Rate [Member] | | | |
Impaired loans, measurement input | 0.1075 | 0.1075 | |
Real Estate Portfolio Segment [Member] | Farmland [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | | | |
Impaired loans, fair value | $ 337 | $ 350 | |
Real Estate Portfolio Segment [Member] | Farmland [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | (0.71) | (0.71) | |
Real Estate Portfolio Segment [Member] | Farmland [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 0.1 | 0.1 | |
Real Estate Portfolio Segment [Member] | Farmland [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | 0.887 | 0.887 | |
Real Estate Portfolio Segment [Member] | Farmland [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 80 | 0.75 | |
Real Estate Portfolio Segment [Member] | Farmland [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | | 0.0885 | |
Real Estate Portfolio Segment [Member] | Farmland [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 0.0885 | 0.425 | |
Other Real Estate Owned, measurement input | 0.45 | | |