Note 26 - Unaudited Quarterly Operating Results - Quarterly Financial Data (Unaudited) (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
Interest income	$ 11,248,939	$ 11,581,621	$ 11,299,507	$ 11,096,436	$ 11,532,388	$ 13,377,875	$ 10,379,125	$ 7,956,316	$ 45,226,503	$ 43,245,704	$ 29,440,733
Interest expense	3,304,666	3,459,478	3,449,152	3,321,718	2,946,828	2,648,869	2,406,858	1,925,064	13,535,014	9,927,619	6,086,554
Net interest income	7,944,273	8,122,143	7,850,355	7,774,718	8,585,560	10,729,006	7,972,267	6,031,252	31,691,489	33,318,085	23,354,179
Provision for loan losses	0	100,000	100,000	0	300,000	200,000	500,000	225,000	200,000	1,225,000	1,750,000
Gain on loans and investment securities	752,688	1,055,589	888,300	645,469	609,521	858,254	831,919	553,602
Other noninterest income, net	917,402	881,541	1,045,038	918,866	1,207,810	603,504	1,121,893	765,437
Noninterest expense	6,874,636	6,953,456	6,826,483	6,843,559	7,093,992	6,665,849	10,222,637	5,475,855	27,498,134	29,458,333	19,603,086
Income before income taxes	2,739,727	3,005,817	2,857,210	2,495,494	3,008,899	5,324,915	(796,558)	1,649,436	11,098,248	9,186,692	7,728,413
Provision for income taxes	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
Net income available to common shareholders	$ 2,315,685	$ 2,550,542	$ 2,428,499	$ 2,120,364	$ 2,384,876	$ 3,934,242	$ (342,984)	$ 1,355,745	$ 9,415,090	$ 7,331,879	$ 5,157,664
Basic income per common share (in dollars per share)	$ 0.54	$ 0.58	$ 0.55	$ 0.48	$ 0.54	$ 0.89	$ (0.08)	$ 0.31	$ 2.14	$ 1.66	$ 1.18
Diluted income per common share (in dollars per share)	$ 0.53	$ 0.57	$ 0.54	$ 0.47	$ 0.53	$ 0.88	$ (0.08)	$ 0.30	$ 2.11	$ 1.64	$ 1.16