Business Combinations (Narratives) (Details)	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($) segment	Jul. 01, 2016 USD ($)	Jun. 30, 2017 USD ($) segment acquisition	Jul. 01, 2016 USD ($)	Dec. 30, 2016 segment
Business Acquisition [Line Items]
Number of Reportable Segments | segment		4		4		4
Gain (Loss) on Disposition of Business				$ 8,000,000	$ 2,700,000
Number of Businesses Acquired | acquisition				7
Business Acquisition, Transaction Costs	$ 4,300,000		$ 900,000	$ 6,400,000	2,500,000
Goodwill, Impairment Loss		$ 0
Maximum
Business Acquisition [Line Items]
Revenue of Business Acquiree Since Acquisition Date Percentage of Total Revenue				1.00%
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Cash Payments to Acquire Businesses				$ 158,000,000
General and Administrative Expense [Member]
Business Acquisition [Line Items]
Business Acquisition, Transaction Costs	$ 4,300,000		$ 900,000	$ 6,400,000	$ 2,500,000