Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	$ 33,436		$ 33,436
Amortization of Intangible Assets	10,500	$ 9,400	17,300	$ 18,000
Finite-Lived Intangible Assets, Gross	339,007		339,007		$ 289,449
Finite-Lived Intangible Assets, Accumulated Amortization	(186,606)		(186,606)		(168,369)
Finite-Lived Intangible Assets, Amortization Expense, Year Two	28,033		28,033
Finite-Lived Intangible Assets, Amortization Expense, Year Three	23,873		23,873
Finite-Lived Intangible Assets, Amortization Expense, Year Four	21,282		21,282
Finite-Lived Intangible Assets, Amortization Expense, Year Five	18,572		18,572
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	27,205		$ 27,205
Finite-Lived Intangible Assets, Net					152,401
Customer Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			7 years 3 months	5 years 6 months
Finite-Lived Intangible Assets, Gross	301,082		$ 301,082		251,025
Finite-Lived Intangible Assets, Accumulated Amortization	(153,598)		$ (153,598)		(136,895)
Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			3 months	0 months
Finite-Lived Intangible Assets, Gross	16,285		$ 16,285		13,550
Finite-Lived Intangible Assets, Accumulated Amortization	(15,276)		$ (15,276)		(13,550)
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			4 years 1 month	4 years 9 months
Finite-Lived Intangible Assets, Gross	21,640		$ 21,640		24,874
Finite-Lived Intangible Assets, Accumulated Amortization	(17,732)		(17,732)		(17,924)
Tradenames And Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	$ 622,575		$ 622,575		$ 575,091