Pension and Profit Sharing - Amounts Recognized in Other Comprehensive Income (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Retirement Benefits [Abstract]
Balance at beginning of the year	$ 1,130,815	$ 1,426,030
Change in net loss	(106,725)	(169,818)
Amortization of actuarial loss	(108,052)	(124,854)
Amortization of prior service cost	(543)	(543)
Change recognized in other comprehensive income	(215,320)	(295,215)
Total recognized in other comprehensive income	915,495	1,130,815
Amounts recognized in accumulated other comprehensive income:
Net actuarial loss			$ 913,870	$ 1,128,647
Prior service cost			1,625	2,168
Total	$ 1,130,815	$ 1,426,030	$ 915,495	$ 1,130,815