Note 5 - Premises and Equipment - Components of Premises and Equipment (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Land	$ 13,466,930	$ 12,936,223
Buildings (useful lives 15 to 50 years)	53,633,788	51,546,499
Furniture and equipment (useful lives 3 to 10 years)	31,984,631	28,458,946
Premises and equipment	99,085,349	92,941,668
Less accumulated depreciation	36,247,094	32,298,160
Premises and equipment, net	$ 62,838,255	$ 60,643,508