Note 2 - Debt Securities (Details Textual) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Other-than-temporary Impairment Loss, Debt Securities, Portion Recognized in Earnings, Total	$ 0
Number of Securities in Unrealized Loss Position	15	6
Percentage of Combined Depreciation of Combined Reported Value of Aggregate Securities Portfolio	0.76%	0.12%
Security Owned and Pledged as Collateral, Fair Value, Total	$ 23,800	$ 36,560