Acquisitions (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 29, 2013 Series of Individually Immaterial Business Acquisitions [Member] Acquisitions	Dec. 31, 2012 Series of Individually Immaterial Business Acquisitions [Member] Acquisitions
Business Acquisition [Line Items]
Number of Businesses Acquired		1	7
Business Acquisition, Purchase Price Allocation [Abstract]
Business Acquisition, Cash Consideration Paid		$ 9,952	$ 289,782
Business Acquisition, Contingent Consideration		570	10,390
Payments to acquire additional interest in majority-owned subsidiary	$ 2,526