Note 2 - Available-for-sale Securities - Scheduled Maturities (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Due in one year or less, Amortized Cost	$ 1,594,256
Due in one year or less, Fair Value	1,602,511
Due after one to five years, Amortized Cost	22,206,122
Due after one to five years, Fair Value	21,906,863
Due after five to ten years, Amortized Cost	3,243,270
Due after five to ten years, Fair Value	3,206,135
Due after ten years, Amortized Cost	0
Due after ten years, Fair Value	0
Total, Amortized Cost	27,043,648	$ 31,951,014
Total, Fair Value	$ 26,715,509