Retirement Agreements and Other Postretirement Benefit Plan Components of Net Periodic Benefit Cost (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement Benefits [Abstract]
Service cost - benefits earned during the year	$ 0	$ 10,180	$ 16,748
Interest cost on the projected benefit obligation	36,869	35,123	30,772
Amortization of unrecognized prior service cost	0	0	4,390
Amortization of unrecognized losses	8,612	8,941	3,514
Net periodic benefits costs	$ 45,481	$ 54,244	$ 55,424