Note 7 - Employee Benefits (Details Textual)	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Employee Stock Ownership Plan (ESOP), Service Hours During Twelve Month Period	1,000		1,000
Employee Stock Ownership Plan (ESOP), Debt Structure, Amortization Period (Year)			20 years
Employee Stock Ownership Plan (ESOP), Debt Structure, Estimated Interest Rate	2.46%		2.46%
Employee Stock Ownership Plan (ESOP), Principal and Interest Payments from ESOP			$ 835,000
Employee Stock Ownership Plan (ESOP), Compensation Expense, Net of Dividends Received	$ 99,000	$ 185,000	$ 359,000	$ 512,000