Credit Agreement (Details) (USD $)	9 Months Ended
	Sep. 28, 2013	Dec. 29, 2012	Sep. 29, 2012
Line of Credit Facility [Line Items]
Senior credit facility, maximum borrowing capacity	$ 250,000,000
Line of credit facility increase option	150,000,000
Line of credit facility, expiration date	Oct. 31, 2016
Senior Credit Facility amount outstanding	40,000,000	0	0
Percentage of additional interest added to LIBOR minimum	0.40%
Percentage of additional interest added to LIBOR maximum	1.00%
Percentage of additional interest added to LIBOR	0.50%
Commitment fee minimum	0.08%
Commitment fee maximum	0.20%
Commitment fee for unused capacity	0.10%
Letters Of Credit [Member]
Line of Credit Facility [Line Items]
Letters of credit under senior credit facility amount outstanding	47,300,000
Swing Loan [Member]
Line of Credit Facility [Line Items]
Swing loan maximum borrowing capacity	$ 20,000,000