Employee Retirement Plans Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jul. 01, 2017 USD ($)	Jun. 30, 2018 USD ($) plan	Jul. 01, 2017 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net Periodic Benefit Cost, Other Components	$ 9,116	$ 8,612	$ 18,821	$ 16,950
Number of defined contribution 401K savings plans | plan			2
Non-US Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(18,895)	(17,323)	$ (38,173)	(34,097)
Defined Benefit Plan, Service Cost	957	996	1,934	1,960
Defined Benefit Plan, Interest Cost	8,113	8,017	16,391	15,781
Defined Benefit Plan, Amortization of Gain (Loss)	1,012	743	2,044	1,463
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment	677	0	964	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	(23)	(49)	(47)
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement				97
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ (8,159)	$ (7,616)	$ (16,887)	$ (14,990)