Note 11 - Fair Value of Financial Instruments and Fair Value Measurements - Quantitative Information for Financial Instruments Measured at Fair Value (Details) $ in Thousands | Mar. 31, 2019USD ($) | Dec. 31, 2018USD ($) | Dec. 31, 2017USD ($) |
Other Real Estate Owned, fair value | $ 1,635 | $ 1,841 | $ 4,256 |
Fair Value, Nonrecurring [Member] | | | |
Impaired loans, fair value | 1,708 | 3,352 | |
Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | | | |
Impaired loans, fair value | 1,708 | 3,352 | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | | | |
Other Real Estate Owned, fair value | $ 1,123 | $ 1,183 | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Other Real Estate Owned, measurement input | (0.3) | (0.3) | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Appraised Value [Member] | | | |
Other Real Estate Owned, measurement input | 0.0982 | 0.0982 | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Other Real Estate Owned, measurement input | 0.2502 | 0.2502 | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Appraised Value [Member] | | | |
Other Real Estate Owned, measurement input | 0.9939 | 0.9939 | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Other Real Estate Owned, measurement input | (0.0249) | (0.0249) | |
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Appraised Value [Member] | | | |
Other Real Estate Owned, measurement input | 0.3812 | 0.3526 | |
Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, 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, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Discount Rate [Member] | | | |
Other Real Estate Owned, measurement input | 0.1 | | |
Real Estate Portfolio Segment [Member] | Residential [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | | | |
Impaired loans, fair value | $ 215 | $ 213 | |
Real Estate Portfolio Segment [Member] | Residential [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | (0.1086) | (0.1086) | |
Real Estate Portfolio Segment [Member] | Residential [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 0 | 0 | |
Real Estate Portfolio Segment [Member] | Residential [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | 0.067 | 0.067 | |
Real Estate Portfolio Segment [Member] | Residential [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, 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, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | (0.0208) | (0.0208) | |
Real Estate Portfolio Segment [Member] | Residential [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 0.125 | 0.125 | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | | | |
Impaired loans, fair value | | $ 360 | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | | (0.06) | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | | 0 | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | | 19.75 | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | | 0.1 | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | | 9.842 | |
Real Estate Portfolio Segment [Member] | Commercial Construction [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | | 0.05 | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, 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, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | | 0.35 | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | | 0.175 | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | | | |
Impaired loans, fair value | $ 1,166 | $ 2,415 | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Minimum [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, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | | (0.6) | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Maximum [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, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | | 0.8 | |
Real Estate Portfolio Segment [Member] | Commercial [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Comparability Adjustment [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, 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, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Cap Rate [Member] | | | |
Impaired loans, measurement input | 0.105 | 0.1013 | |
Real Estate Portfolio Segment [Member] | Farmland [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | | | |
Impaired loans, fair value | $ 327 | $ 328 | |
Real Estate Portfolio Segment [Member] | Farmland [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, 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, 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, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | (0.035) | (0.035) | |
Real Estate Portfolio Segment [Member] | Farmland [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 0.8 | 0.8 | |
Real Estate Portfolio Segment [Member] | Farmland [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Comparability Adjustment [Member] | | | |
Impaired loans, measurement input | (0.3725) | (0.3725) | |
Real Estate Portfolio Segment [Member] | Farmland [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | 0.45 | 0.45 | |
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | | | |
Impaired loans, fair value | | $ 36 | |
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | | 0 | |
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Minimum [Member] | Measurement Input, Cost to Sell [Member] | | | |
Impaired loans, measurement input | | 0 | |
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Appraised Value [Member] | | | |
Impaired loans, measurement input | | 0.15 | |
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Maximum [Member] | Measurement Input, Cost to Sell [Member] | | | |
Impaired loans, measurement input | | 0 | |
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Cap Rate [Member] | | | |
Impaired loans, measurement input | | 0.15 | |
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Measurement Input, Cost to Sell [Member] | | | |
Impaired loans, measurement input | | 0 | |