Note 12 - Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets
Allowance for loan losses	$ 626,841	$ 627,127
Other real estate owned allowance for loss	228,354	213,123
Write-down of equity securities	12,631	4,265
Nonaccrual interest	31,692	22,804
Post-retirement benefits	502,661	434,891
Unrealized loss on securities available for sale	215,751	149,671
Deferred Tax Assets, Net of Valuation Allowance, Total	1,617,930	1,451,881
Deferred tax liabilities
Prepaid captive insurance premium	273,665	282,990
Depreciation	164,811	170,859
Deferred Tax Liabilities, Total	438,476	453,849
Net deferred tax asset	$ 1,179,454	$ 998,032