Note 9 - Disclosures About Fair Value of Assets and Liabilities - Fair Value Quantitative Information (Details) - Fair Value, Inputs, Level 3 [Member] - Valuation, Market Approach [Member] $ in Thousands	Mar. 31, 2018 USD ($)
Impaired loans, fair value	$ 2,378
Foreclosed assets held for sale, fair value
Minimum [Member] | Measurement Input, Discount Rate [Member]
Impaired loans, discount rate	0
Maximum [Member] | Measurement Input, Discount Rate [Member]
Impaired loans, discount rate	100
Weighted Average [Member] | Measurement Input, Discount Rate [Member]
Impaired loans, discount rate	(12)