Net Sales by Major Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2018		Jul. 01, 2017		Jun. 30, 2018	Jul. 01, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 668,128	[1]	$ 579,343	[1]	$ 1,252,928	$ 1,109,640

[1] Non-operating expenses are not allocated to the operating segments. Non-operating expenses consist of interest expense and deferred financing amortization, foreign exchange gains and losses and other income and expense items outside of income from operations.