Note 20 - Parent Company Only Financial Statements - Condensed Statements of Income (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Total interest income	$ 52,704,261	$ 49,830,471	$ 40,798,214	$ 39,546,296	$ 37,878,086	$ 33,840,865	$ 32,453,268	$ 31,345,099
Securities gains (losses), net										$ (87,885)	$ 4,592,398
Total interest expense	13,109,573	11,516,988	8,713,718	7,143,378	6,084,733	5,284,517	4,406,571	3,676,216	$ 40,483,657	19,452,037	11,950,958
Salaries and employee benefits									68,994,218	55,722,288	46,317,060
Business acquisition related costs									1,795,119	1,068,918	1,400,004
Post-acquisition compensation, transition and integration costs									2,086,386	4,309,565	1,041,169
Losses on debt extinguishment, net											4,577,668
Income tax benefit	(3,535,188)	(1,608,035)	(1,880,819)	(1,991,070)	2,000,105	(1,921,533)	(2,635,576)	(2,389,446)	(9,015,112)	(4,946,450)	(8,902,787)
Net income (loss)	$ 13,315,518	$ 8,808,835	$ 10,445,385	$ 10,549,961	$ 9,901,590	$ 7,853,935	$ 8,766,017	$ 9,184,965	43,119,699	35,706,507	27,686,787
Parent Company [Member]
Total interest income									87,532	12,802	74,489
Securities gains (losses), net										6,312	37,596
Other									(322,119)	2,700	(2,933)
Total revenue									54,538,854	45,200,751	33,609,538
Total interest expense									3,637,126	2,658,414	1,735,769
Salaries and employee benefits									6,597,881	5,021,998	4,607,887
Professional fees									1,871,655	1,344,721	949,442
Business acquisition related costs									1,654,323	1,068,918	1,400,004
Post-acquisition compensation, transition and integration costs									165,314	3,151,384	313,598
Losses on debt extinguishment, net											(1,200,000)
Other									1,026,016	1,134,139	988,057
Total expenses									14,952,315	14,379,574	8,794,757
Income before income tax benefit									39,586,539	30,821,177	24,814,781
Income tax benefit									3,533,160	4,885,330	2,872,006
Net income (loss)									43,119,699	35,706,507	27,686,787
Parent Company [Member] | Bank Subsidiaries [Member]
Equity in net income of bank subsidiaries									55,209,382	45,103,593	33,467,712
Parent Company [Member] | Non-bank Subsidiaries [Member]
Equity in net income of bank subsidiaries									$ (435,941)	$ 75,344	$ 32,674