Acquisitions (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 30, 2013 Acquisitions	Dec. 31, 2012 Acquisitions
Business Acquisition, Purchase Price Allocation [Abstract]
Payments to acquire additional interest in majority-owned subsidiary		$ 2,526
Series of Individually Immaterial Business Acquisitions [Member]
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