Reconciliation of Total Segment Profit to Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Segment Profit	$ 95,884	$ 81,324	$ 292,063	$ 225,424
Amortization	21,419	11,051	45,102	33,003
Unallocated General And Administrative Expenses	6,490	9,618	25,580	21,756
Operating income	67,975	60,655	221,381	170,665
Interest expense	7,987	7,749	24,442	24,418
Interest income	(309)	(150)	(2,613)	(323)
Other income, net	810	2,906	4,826	3,762
Income before income tax expense	$ 59,487	$ 50,150	$ 194,726	$ 142,808