Note 20 - Parent Company Only Financial Statements - Condensed Statements of Income (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Total interest income	$ 37,878,086	$ 33,840,865	$ 32,453,268	$ 31,345,099	$ 32,235,657	$ 26,816,735	$ 23,913,284	$ 23,502,059
Securities gains									$ (87,885)	$ 4,592,398	$ 798,983
Total revenue									165,999,610	137,502,624	114,366,574
Total interest expense	6,084,733	5,284,517	4,406,571	3,676,216	2,955,992	3,185,958	2,904,471	2,904,537	19,452,037	11,950,958	13,706,529
Salaries and employee benefits									55,722,288	46,317,060	42,967,915
Business Combination, Acquisition Related Costs									1,068,918	1,400,004
Post-acquisition compensation, transition and integration costs									4,309,565	1,041,169
Losses on debt extinguishment, net										4,577,668	7,185,601
Income tax benefit	2,000,105	(1,921,533)	(2,635,576)	(2,389,446)	(2,872,412)	(1,858,208)	(2,153,144)	(2,019,023)	(4,946,450)	(8,902,787)	(3,669,242)
Net income (loss)	$ 9,901,590	$ 7,853,935	$ 8,766,017	$ 9,184,965	$ 8,529,330	$ 6,107,501	$ 6,676,467	$ 6,373,489	35,706,507	27,686,787	16,927,881
Parent Company [Member]
Total interest income									12,802	74,489	69,774
Securities gains									6,312	37,596	262,801
Other									2,700	(2,933)	(4,436)
Total revenue									45,200,751	33,609,538	22,420,047
Total interest expense									2,658,414	1,735,769	1,679,909
Salaries and employee benefits									5,021,998	4,607,887	4,847,507
Professional fees									1,344,721	949,442	1,121,094
Business Combination, Acquisition Related Costs									1,068,918	1,400,004
Post-acquisition compensation, transition and integration costs									3,151,384	313,598
Losses on debt extinguishment, net										(1,200,000)	(300,000)
Other									1,134,139	988,057	949,041
Total expenses									14,379,574	8,794,757	8,297,551
Income before income tax benefit									30,821,177	24,814,781	14,122,496
Income tax benefit									4,885,330	2,872,006	2,805,385
Net income (loss)									35,706,507	27,686,787	16,927,881
Parent Company [Member] | Bank Subsidiaries [Member]
Equity in net income of bank subsidiaries									45,103,593	33,467,712	22,059,086
Parent Company [Member] | Non-bank Subsidiaries [Member]
Equity in net income of bank subsidiaries									$ 75,344	$ 32,674	$ 32,823