Note 26 - Unaudited Quarterly Operating Results - Quarterly Financial Data (Unaudited) (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
Interest income	$ 9,943,705	$ 9,968,256	$ 10,159,058	$ 10,798,857	$ 11,248,939	$ 11,581,621	$ 11,299,507	$ 11,096,436	$ 40,869,876	$ 45,226,503	$ 43,245,704
Interest expense	2,151,524	2,236,743	2,136,409	3,086,525	3,304,666	3,459,478	3,449,152	3,321,718	9,611,201	13,535,014	9,927,619
Net interest income	7,792,181	7,731,513	8,022,649	7,712,332	7,944,273	8,122,143	7,850,355	7,774,718	31,258,675	31,691,489	33,318,085
Provision for loan losses	1,400,000	950,000	750,000	500,000	0	100,000	100,000	0	3,600,000	200,000	1,225,000
Gain on loans and investment securities	1,199,622	1,992,185	1,018,516	571,310	752,688	1,055,589	888,300	645,469
Other noninterest income, net	1,191,641	1,278,146	1,294,202	1,527,822	917,402	881,541	1,045,038	918,866
Noninterest expense	7,877,518	7,735,249	7,253,331	6,798,629	6,874,636	6,953,456	6,826,483	6,843,559	29,664,727	27,498,134	29,458,333
Income before income taxes	905,926	2,316,595	2,332,036	2,512,835	2,739,727	3,005,817	2,857,210	2,495,494	8,067,392	11,098,248	9,186,692
Provision for income taxes	(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
Net income available to common shareholders	$ 946,210	$ 1,897,776	$ 1,883,383	$ 2,104,845	$ 2,315,685	$ 2,550,542	$ 2,428,499	$ 2,120,364	$ 6,832,214	$ 9,415,090	$ 7,331,879
Basic income per common share (in dollars per share)	$ 0.22	$ 0.44	$ 0.43	$ 0.49	$ 0.54	$ 0.58	$ 0.55	$ 0.48	$ 1.58	$ 2.14	$ 1.66
Diluted income per common share (in dollars per share)	$ 0.22	$ 0.43	$ 0.43	$ 0.49	$ 0.53	$ 0.57	$ 0.54	$ 0.47	$ 1.57	$ 2.11	$ 1.64