Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	$ 33,402		$ 33,402
Amortization of Intangible Assets	9,100	$ 5,100	26,500	$ 23,100
Finite-Lived Intangible Assets, Gross	346,337		346,337		$ 289,449
Finite-Lived Intangible Assets, Accumulated Amortization	(195,835)		(195,835)		(168,369)
Finite-Lived Intangible Assets, Amortization Expense, Year Two	27,243		27,243
Finite-Lived Intangible Assets, Amortization Expense, Year Three	25,054		25,054
Finite-Lived Intangible Assets, Amortization Expense, Year Four	21,566		21,566
Finite-Lived Intangible Assets, Amortization Expense, Year Five	18,919		18,919
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	24,318		24,318
Finite-Lived Intangible Assets, Net	150,502		$ 150,502
Customer Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			5 years 1 month	5 years 6 months
Finite-Lived Intangible Assets, Gross	307,502		$ 307,502		251,025
Finite-Lived Intangible Assets, Accumulated Amortization	(161,823)		$ (161,823)		(136,895)
Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			2 months	0 months
Finite-Lived Intangible Assets, Gross	16,030		$ 16,030		13,550
Finite-Lived Intangible Assets, Accumulated Amortization	(15,963)		$ (15,963)		(13,550)
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			4 years 2 months	4 years 9 months
Finite-Lived Intangible Assets, Gross	22,805		$ 22,805		24,874
Finite-Lived Intangible Assets, Accumulated Amortization	(18,049)		(18,049)		(17,924)
Tradenames And Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	$ 635,850		$ 635,850		$ 575,091