Retirement Benefit Plans, Defined Contribution Plan (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Defined Contribution Plan [Abstract]
Total contributions for the period	$ 205,120	$ 215,811	$ 1,281,688	$ 1,268,377
Regular Matching Contribution [Member]
Defined Contribution Plan [Abstract]
Total contributions for the period	125,266	129,968	418,329	436,088
Transitional Credit Contribution [Member]
Defined Contribution Plan [Abstract]
Total contributions for the period	62,464	68,128	240,840	273,742
Non-discretionary Contribution [Member]
Defined Contribution Plan [Abstract]
Total contributions for the period	$ 17,390	$ 17,715	622,519	$ 558,547
Non-Union U.S. Employees [Member]
Defined Contribution Plan [Abstract]
Total contributions for the period			$ 565,748