Note 7 - Fair Value Measurements - Level 3 Fair Value Measurements (Details) - Valuation, Market Approach [Member]		Mar. 31, 2020	Dec. 31, 2019
Measurement Input, Discount Rate [Member] | Minimum [Member]
Discount rate	[1]	0.055	0.055
Measurement Input, Discount Rate [Member] | Maximum [Member]
Discount rate	[1]	0.065	0.065
Measurement Input, Discount Rate [Member] | Weighted Average [Member]
Discount rate	[1]	(0.0577)	(0.0577)
Measurement Input, Cost to Sell [Member] | Minimum [Member]
Level 3 Fair Value Measurements	[2],[3]	0	0
Measurement Input, Cost to Sell [Member] | Maximum [Member]
Level 3 Fair Value Measurements	[2]	0.1	0.06
Measurement Input, Cost to Sell [Member] | Weighted Average [Member]
Level 3 Fair Value Measurements	[2]	(0.0065)	(0.0068)
Measurement Input, Discount for Lack of Marketability and Age of Appraisal [Member] | Minimum [Member]
Level 3 Fair Value Measurements	[2]	0	0
Measurement Input, Discount for Lack of Marketability and Age of Appraisal [Member] | Maximum [Member]
Level 3 Fair Value Measurements	[2]	0.04	0.4517
Measurement Input, Discount for Lack of Marketability and Age of Appraisal [Member] | Weighted Average [Member]
Level 3 Fair Value Measurements	[2]	(0.0033)	(0.0128)

[1] Unobservable inputs were weighted by the relative fair value of the impaired loans.

[2] Discounts were weighted by the relative appraised value of the OREO properties.

[3] The appraised value is discounted by selling costs if the OREO property is listed with a realtor and if appraised value exceeds the list price, less estimated selling costs. Selling costs do not discount appraised value if the Company markets the OREO property independently or if the OREO property is listed with a realtor and the list price less estimated selling costs exceeds appraised value.