Investments, Investments with Sustained Gross Unrealized Losses (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 6,059,380	$ 59,724,349
12 months or longer, fair value	0	16,930,418
Total fair value	6,059,380	76,654,767
Less than 12 months, unrealized losses	(35,529)	(2,087,817)
12 months or longer, unrealized losses	0	(899,861)
Total unrealized losses	(35,529)	(2,987,678)
U.S. Government and Govt. Agencies and Authorities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	6,059,380	6,429,700
12 months or longer, fair value	0	1,592,679
Total fair value	6,059,380	8,022,379
Less than 12 months, unrealized losses	(35,529)	(49,904)
12 months or longer, unrealized losses	0	(88,318)
Total unrealized losses	$ (35,529)	(138,222)
U.S. Special Revenue and Assessments [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value		4,023,920
12 months or longer, fair value		0
Total fair value		4,023,920
Less than 12 months, unrealized losses		(4,406)
12 months or longer, unrealized losses		0
Total unrealized losses		(4,406)
All Other Corporate Bonds [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value		49,270,729
12 months or longer, fair value		15,337,739
Total fair value		64,608,468
Less than 12 months, unrealized losses		(2,033,507)
12 months or longer, unrealized losses		(811,543)
Total unrealized losses		$ (2,845,050)