Employee Retirement Plans Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) plan	Apr. 01, 2017 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net Periodic Benefit Cost, Other Components	$ 9,705	$ 8,338
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	$ (19,278)	(16,774)
Defined Benefit Plan, Service Cost	977	964
Defined Benefit Plan, Interest Cost	8,278	7,764
Defined Benefit Plan, Amortization of Gain (Loss)	1,032	720
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment	287	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	(24)
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement		48
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ (8,728)	$ (7,374)