Employee Benefit Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2019	Sep. 30, 2018	Sep. 29, 2019	Sep. 30, 2018
Nora Defined Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 213	$ 134	$ 646	$ 134
Interest cost	170	99	515	99
Net periodic benefit cost	383	233	1,161	233
Foreign Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	181	178	550	547
Interest cost	1,223	1,270	3,770	3,941
Expected return on assets	(1,378)	(1,503)	(4,251)	(4,667)
Amortization of prior service cost	16	(11)	48	4
Amortization of net actuarial losses	240	270	742	839
Net periodic benefit cost	282	204	859	664
United States | Salary Continuation Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0	0	0	0
Interest cost	288	271	865	812
Amortization of net actuarial losses	94	116	281	348
Net periodic benefit cost	$ 382	$ 387	$ 1,146	$ 1,160