Retirement Benefit Plans (Details) - USD ($)	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Additional information [Abstract]
Reduction in pension expense	$ 135,000
Pension Benefits [Member]
Components of the net periodic benefit cost [Abstract]
Service cost	317,360	$ 813,005
Interest cost	791,057	766,580
Expected return on plan assets	(1,195,895)	(1,243,941)
Amortization of prior service cost	36,438	50,143
Amortization of the net loss	307,870	627,055
Net periodic benefit cost	256,830	1,012,842
Additional information [Abstract]
Contributions required by the Company in defined benefit plan	103,000
Postretirement Benefits [Member]
Components of the net periodic benefit cost [Abstract]
Service cost	6,847	10,750
Interest cost	20,207	20,500
Expected return on plan assets	(12,874)	(11,750)
Amortization of prior service cost	(5,361)	(6,000)
Amortization of the net loss	(19,400)	(13,500)
Net periodic benefit cost	(10,581)	$ 0
Additional information [Abstract]
Contributions required by the Company in defined benefit plan	700,000
Employer contributions made	$ 45,000