Fair Value Measurements (Narrative) (Details) (USD $)	Apr. 01, 2012	Jan. 01, 2012	Apr. 03, 2011	Jan. 02, 2011	Apr. 01, 2012 2015 Notes [Member]	Jan. 01, 2012 2015 Notes [Member]	May 30, 2008 2015 Notes [Member]	Apr. 01, 2012 2021 Notes [Member]	Jan. 01, 2012 2021 Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	$ 20,636,000	$ 20,298,000	$ 15,645,000	$ 1,731,000
Business Acquisition, Contingent Consideration, Potential Cash Payment	50,800,000
Unsecured revolving credit facility, amount	700,000,000
Unsecured senior notes, face value					150,000,000		150,000,000	500,000,000
Revolving credit facility outstanding balance	287,000,000	298,000,000
Unsecured senior notes, carrying value					150,000,000	150,000,000		497,000,000	496,900,000
Debt Instrument, Unamortized Discount								3,000,000	3,100,000
Unsecured senior notes, fair value					$ 164,500,000	$ 165,700,000		$ 520,000,000	$ 518,300,000