Pension and Profit Sharing - Periodic Benefit Cost (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assumptions used to determine net periodic benefit cost:
Discount rate		3.40%	3.50%
Expected return on plan assets		6.00%	6.00%
Components of net benefit expense:
Interest cost		$ 48,161	$ 55,811
Service cost	$ 1,000	36,000	36,000
Expected return on plan assets		(69,465)	(76,138)
Amortization of prior service costs		543	543
Amortization of actuarial loss		108,052	124,854
Net periodic benefit cost		$ 123,291	$ 141,070