Note 14 - Income Taxes - The Provision for Income Taxes (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Taxes currently payable									$ 1,459,016	$ 1,230,427	$ 1,490,297
Deferred income taxes									224,142	624,386	68,340
Deferred income taxes related to 2017 Tax Act											1,012,112
	$ 424,042	$ 455,275	$ 428,711	$ 375,130	$ 624,023	$ 1,390,673	$ (453,574)	$ 293,691	$ 1,683,158	$ 1,854,813	$ 2,570,749