Cost in Excess of Net Assets of Companies Acquired - Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended			12 Months Ended
	Jul. 02, 2016		Jun. 27, 2015	Jul. 02, 2016		Jun. 27, 2015	Dec. 31, 2015
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 617,608			$ 617,608			$ 613,390
Accumulated Amortization	(252,005)			(252,005)			(224,064)
Net	365,603			365,603			$ 389,326
Amortization of Intangible Assets	14,446		$ 13,917	$ 27,359		$ 25,024
Customer Relationships [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Weighted-Average Life				10 years			10 years
Gross Carrying Amount	494,506			$ 494,506			$ 498,319
Accumulated Amortization	(238,118)			(238,118)			(215,263)
Net	256,388			$ 256,388			$ 283,056
Developed Technology [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Weighted-Average Life				5 years			5 years
Gross Carrying Amount	14,199			$ 14,199			$ 13,154
Accumulated Amortization	(10,203)			(10,203)			(7,894)
Net	3,996			3,996			5,260
Other Intangible Assets [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,903	[1]		7,903	[1]		917	[2]
Accumulated Amortization	(3,684)	[1]		(3,684)	[1]		(907)	[2]
Net	4,219	[1]		4,219	[1]		10	[2]
Trade Names [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	101,000			101,000			101,000
Accumulated Amortization	0			0			0
Net	$ 101,000			$ 101,000			$ 101,000
Minimum [Member] | Other Intangible Assets [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Useful Life				2 years			2 years
Maximum [Member] | Other Intangible Assets [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Useful Life				5 years			3 years

[1] Consists of non-competition agreements, sales backlog, and an amortizable trade name with useful lives ranging from two to five years.

[2] Consists of non-competition agreements with useful lives ranging from two to three years.