Note 12 - Income Taxes - Net Deferred Tax Asset (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Employee benefit plans	$ 818,437	$ 1,033,250
Allowance for loan losses	704,647	885,495
Net operating loss carryforwards	181,212	371,570
MRP and RRP compensation	132,252	182,856
Loans	84,268	191,434
Purchase accounting - acquisition expenses	90,076	133,904
Other	43,844	46,944
	2,054,736	2,845,453
Unrealized gain on securities available for sale	(60,834)	(44,473)
Prepaid expenses	(23,973)	(38,349)
Origination of mortgage servicing rights	(17,916)	(28,423)
Core deposit intangible	(81,523)	(140,422)
	(184,246)	(251,667)
Net deferred tax asset	$ 1,870,490	$ 2,593,786