Investments in Securities and Fair Value Schedule of Gross Unrealized Gains and Losses and Amortized Cost for Securities (Details)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Available-for-sale Securities [Abstract]
Amortized Cost	$ 100,314,085	$ 100,162,357
Gross Unrealized Gains	3,251,396	2,572,388
Gross Unrealized Losses	224,398	800,668
Estimated Fair Value	103,341,083	101,934,077
Amortized Cost	26,002,619	24,836,032
Available For Sale Equity Securities Gross Unrealized Gains	21,376,110	16,392,210
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax	11,903	48,983
Estimated Fair Value	47,366,826	41,179,259
Short Term Investments Amortized Cost Basis	23,779,672	6,558,840
Short Term Investments Gross Unrealized Gains	0	0
Short Term Investments Gross Unrealized Losses	0	0
Short Term Investments Estimated Fair Value	23,779,672	6,558,840
Government obligations
Available-for-sale Securities [Abstract]
Amortized Cost	1,042,921
Gross Unrealized Gains	0
Gross Unrealized Losses	951
Estimated Fair Value	1,041,970
General obligations of U.S. states, territories and political subdivisions
Available-for-sale Securities [Abstract]
Amortized Cost	24,189,032	29,374,774
Gross Unrealized Gains	505,513	440,628
Gross Unrealized Losses	50,224	298,533
Estimated Fair Value	$ 24,644,321	29,516,869
Special revenue issuer obligations of U.S. states, territories and political subdivisions
Schedule of Trading Securities and Other Trading Assets [Line Items]
Number of Special Revenue Bonds	60
Available-for-sale Securities [Abstract]
Amortized Cost	$ 62,591,978	57,459,818
Gross Unrealized Gains	2,217,665	1,619,444
Gross Unrealized Losses	164,355	502,135
Estimated Fair Value	64,645,288	58,577,127
Corporate debt securities
Available-for-sale Securities [Abstract]
Amortized Cost	12,490,154	13,327,765
Gross Unrealized Gains	528,218	512,316
Gross Unrealized Losses	8,868	0
Estimated Fair Value	13,009,504	13,840,081
Common stocks
Available-for-sale Securities [Abstract]
Amortized Cost	26,002,619	24,836,032
Available For Sale Equity Securities Gross Unrealized Gains	21,376,110	16,392,210
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax	11,903	48,983
Estimated Fair Value	47,366,826	41,179,259
Commercial paper, money market funds and certificates of deposit
Available-for-sale Securities [Abstract]
Short Term Investments Amortized Cost Basis	23,779,672	6,558,840
Short Term Investments Gross Unrealized Gains	0	0
Short Term Investments Gross Unrealized Losses	0	0
Short Term Investments Estimated Fair Value	$ 23,779,672	$ 6,558,840