Retirement Benefit Plans (Details) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 02, 2021	Oct. 03, 2020	Oct. 02, 2021	Oct. 03, 2020
Pension Benefit [Member]
Service cost	$ 271,832	$ 266,435	$ 815,500	$ 799,305
Interest cost	504,252	714,143	1,512,761	2,142,428
Expected return on plan assets	(1,448,671)	(1,365,261)	(4,346,020)	(4,095,784)
Amortization of prior service cost	24,845	24,845	74,535	74,535
Amortization of the net loss	432,539	325,033	1,297,614	975,101
Net periodic benefit cost	215,203	34,805	645,610	104,415
Other Postretirement Benefit [Member]
Service cost	13,626	10,855	40,878	32,565
Interest cost	9,842	11,667	29,526	35,001
Expected return on plan assets	(6,420)	(5,589)	(19,260)	(16,767)
Amortization of prior service cost	0	(2,063)	0	(6,189)
Amortization of the net loss	(3,094)	(6,377)	(9,282)	(19,131)
Net periodic benefit cost	(13,954)	(8,493)	(41,862)	(25,479)
Gain on significant event	$ 0	$ 0	$ 0	$ 0