Note 8 - Fair Value Measurements - Additional Information on Assets Measured on a Nonrecurring Basis (Details) - Fair Value, Nonrecurring [Member] - Fair Value, Inputs, Level 3 [Member] - Measurement Input, Discount Rate [Member] - Weighted Average [Member]	Sep. 30, 2020	[1]
Impaired loans	0.10
Other real estate owned	0.10

[1] The fair value is generally determined through independent appraisals of the underlying collateral, which may include Level 3 inputs that are not identifiable, or by using the discounted cash flow method if the loan is not collateral dependent.