Retirement Benefit Plans, Defined Contribution Plan (Details) - USD ($)	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Defined Contribution Plan [Abstract]
Total contributions for the period	$ 854,776	$ 846,832
Regular Matching Contribution [Member]
Defined Contribution Plan [Abstract]
Total contributions for the period	204,992	156,267
Transitional Credit Contribution [Member]
Defined Contribution Plan [Abstract]
Total contributions for the period	82,127	103,524
Non-discretionary Contribution [Member]
Defined Contribution Plan [Abstract]
Total contributions for the period	567,657	$ 587,041
Non-Union U.S. Employees [Member]
Defined Contribution Plan [Abstract]
Total contributions for the period	$ 550,286