Retirement Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Pension Benefits [Member] | U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$ 175	$ 171	$ 525	$ 514
Interest Cost	298	307	894	923
Expected Return on Plan Assets	(322)	(331)	(966)	(994)
Recognized Net Actuarial Loss	135	110	405	331
Amortization of Prior Service Cost	0	14	0	40
Net Periodic Benefit Cost	$ 286	$ 271	$ 858	$ 814
The weighted average assumptions used to determine net periodic benefit cost are as follows:
Discount Rate (as a percentage)	3.51%	4.03%	3.51%	4.03%
Expected Long-Term Return on Plan Assets (as a percentage)	4.50%	5.00%	4.50%	5.00%
Rate of Compensation Increase (as a percentage)	3.00%	3.00%	3.00%	3.00%
Pension Benefits [Member] | Non-U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$ 35	$ 35	$ 106	$ 100
Interest Cost	30	28	90	78
Expected Return on Plan Assets	(11)	(10)	(33)	(27)
Recognized Net Actuarial Loss	15	10	46	28
Amortization of Prior Service Cost	2	2	6	4
Net Periodic Benefit Cost	$ 71	$ 65	$ 215	$ 183
The weighted average assumptions used to determine net periodic benefit cost are as follows:
Discount Rate (as a percentage)	3.86%	3.42%	3.82%	3.43%
Expected Long-Term Return on Plan Assets (as a percentage)	7.43%	7.72%	7.43%	7.72%
Rate of Compensation Increase (as a percentage)	3.72%	3.41%	3.70%	3.42%
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$ 53	$ 43	$ 159	$ 131
Interest Cost	43	43	129	127
Expected Return on Plan Assets	(1)	(1)	(3)	(1)
Recognized Net Actuarial Loss	34	22	102	62
Amortization of Prior Service Cost	22	22	66	66
Net Periodic Benefit Cost	$ 151	$ 129	$ 453	$ 385
The weighted average assumptions used to determine net periodic benefit cost are as follows:
Discount Rate (as a percentage)	3.64%	4.12%	3.64%	4.12%
Expected Long-Term Return on Plan Assets (as a percentage)	7.43%	7.72%	7.43%	7.72%
Rate of Compensation Increase (as a percentage)	3.07%	3.08%	3.07%	3.07%