Note 10 - FHLB Advances - Maturity and Interest Rate Information on Advances from FHLB (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
2020, Amount due	$ 110,900
2020, Weighted average interest rate at year-end	1.73%
2021, Amount due	$ 5,000
2021, Weighted average interest rate at year-end	1.55%
2022, Amount due	$ 23,400
2022, Weighted average interest rate at year-end	1.73%
2023, Amount due	$ 20,000
2023, Weighted average interest rate at year-end	1.84%
Total FHLB advances, Amount due	$ 159,300
Total FHLB advances, Weighted average interest rate at year-end	1.74%
Federal Home Loan Bank, Advances, Putable Option [Member]
2019, Amount due		$ 239,958
2019, Weighted average interest rate at year-end		2.60%
2020, Amount due		$ 11,484
2020, Weighted average interest rate at year-end		1.74%
2021, Amount due		$ 15,050
2021, Weighted average interest rate at year-end		2.32%
Total FHLB advances, Amount due		$ 266,492
Total FHLB advances, Weighted average interest rate at year-end		2.55%