Note 19 - Quarterly Results of Operations (Unaudited) (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
Quarterly Financial Information Disclosure [Abstract]
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
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
Net interest income	39,594,688	38,313,483	32,084,496	32,402,918	31,793,353	28,556,348	28,046,697	27,668,883	142,395,585	116,065,281	94,516,777
Provision for loan/lease losses	1,612,047	6,205,828	2,300,735	2,539,839	2,255,381	2,086,436	2,022,993	2,105,109	12,658,449	8,469,919	7,478,166
Noninterest income	15,278,554	8,808,825	8,912,266	8,541,449	9,714,717	6,701,303	6,782,518	7,283,754	41,541,094	30,482,292	31,036,875
Noninterest expense	36,410,489	30,499,610	26,369,823	25,863,497	31,351,204	23,395,747	21,404,629	21,273,117	119,143,419	97,424,697	81,485,912
Income before taxes	16,850,706	10,416,870	12,326,204	12,541,031	7,901,485	9,775,468	11,401,593	11,574,411	52,134,811	40,652,957	36,589,574
Federal and state income tax expense (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	$ 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
Basic (in dollars per share)	$ 0.85	$ 0.56	$ 0.75	$ 0.76	$ 0.72	$ 0.60	$ 0.67	$ 0.70	$ 2.92	$ 2.68	$ 2.20
Diluted (in dollars per share)	$ 0.84	$ 0.55	$ 0.73	$ 0.74	$ 0.70	$ 0.58	$ 0.65	$ 0.68	$ 2.86	$ 2.61	$ 2.17