Income Taxes Reconciliation of Income Tax (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Anticipated income tax expense	$ 10,594,700	$ 9,733,482	$ 6,115,306
State income taxes, net of federal income tax benefit	46,150	52,974	22,304
Tax-exempt interest income (net of amortization)	(1,298,251)	(1,074,504)	(981,712)
Income tax benefit from Tax Cuts And Jobs Act of 2017	(5,341,521)	0	0
Other, net	568,922	(95,952)	72,102
Total	$ 4,570,000	$ 8,616,000	$ 5,228,000
U.S. Federal statutory income tax rate	35.00%	34.60%	34.40%