Note 15 - Income Taxes - The Provision for Income Taxes (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Taxes currently payable									$ 1,705,323	$ 1,459,016	$ 1,230,427
Deferred income taxes									(470,145)	224,142	624,386
Income Tax Expense (Benefit), Total	$ (40,284)	$ 418,819	$ 448,653	$ 407,990	$ 424,042	$ 455,275	$ 428,711	$ 375,130	$ 1,235,178	$ 1,683,158	$ 1,854,813