Note 6 - Premises and Equipment, Net - Components of Premises and Equipment (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Total cost	$ 17,076,233	$ 16,482,276
Accumulated depreciation and amortization	(6,955,329)	(6,368,806)
Net book value	10,120,904	10,113,470
Land and Land Improvements [Member]
Total cost	2,452,807	2,452,807
Building and Building Improvements [Member]
Total cost	12,218,857	11,649,269
Furniture and Fixtures [Member]
Total cost	2,266,934	2,242,897
Automobiles [Member]
Total cost	$ 137,635	$ 137,303