Employee Benefit Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 05, 2020	Mar. 31, 2019
Nora Defined Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 258	$ 217
Interest cost	111	174
Net periodic benefit cost	369	391
Foreign Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multiemployer Plan, Contributions by Employer	700
Service cost	0	185
Interest cost	891	1,281
Expected return on assets	(1,064)	(1,445)
Amortization of prior service cost	26	16
Amortization of net actuarial losses	326	253
Net periodic benefit cost	179	290
United States | Salary Continuation Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0	0
Interest cost	234	288
Amortization of net actuarial losses	140	94
Net periodic benefit cost	$ 374	$ 382