Consolidated Statements of Comprehensive Income - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net income	$ 35,706,507	$ 27,686,787	$ 16,927,881
Other comprehensive income (loss):
Unrealized holding gains arising during the period before tax	1,257,289	4,258,154	1,144,314
Less reclassification adjustment for gains (losses) included in net income before tax	(87,885)	4,592,398	798,983
	1,345,174	(334,244)	345,331
Unrealized holding losses arising during the period before tax	(69,827)	(279,497)	(631,363)
Less reclassification adjustment for ineffectiveness and caplet amortization before tax	(484,891)	(75,290)	(15,895)
	415,064	(204,207)	(615,468)
Other comprehensive income (loss), before tax	1,760,238	(538,451)	(270,137)
Tax expense (benefit)	668,085	(202,691)	(81,524)
Other comprehensive income (loss), net of tax	1,092,153	(335,760)	(188,613)
Comprehensive income	$ 36,798,660	$ 27,351,027	$ 16,739,268