Note 10 - FHLB Advances - Maturity and Interest Rate Information on Advances from FHLB (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
2019, Amount due	$ 239,957,672
2019, Weighted average interest rate at year-end	2.60%
2020, Amount due	$ 11,484,203
2020, Weighted average interest rate at year-end	1.74%
2021, Amount due	$ 15,050,164
2021, Weighted average interest rate at year-end	2.32%
Total FHLB advances, Amount due	$ 266,492,039
Total FHLB advances, Weighted average interest rate at year-end	2.55%
Federal Home Loan Bank, Advances, Putable Option [Member]
2018, Amount due		$ 190,400,000
2018, Weighted average interest rate at year-end		1.82%
2020, Amount due		$ 1,600,000
2020, Weighted average interest rate at year-end		1.75%
Total FHLB advances, Amount due		$ 192,000,000
Total FHLB advances, Weighted average interest rate at year-end		1.82%