Share Repurchases (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 26, 2012	Dec. 28, 2011	Dec. 29, 2010
Equity, Class of Treasury Stock [Line Items]
Common stock shares repurchased during the period (value in US$)	$ 22,179	$ 21,569	$ 3,890
Share Repurchase Program 2010 [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares approved under stock repurchase program (shares)			3,000,000
Common stock shares repurchased during the period (shares)			1,000,000
Common stock shares repurchased during the period (value in US$)			3,900
Share Repurchase Program 2011 [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares approved under stock repurchase program (shares)		6,000,000
Common stock shares repurchased during the period (shares)		5,700,000
Common stock shares repurchased during the period (value in US$)		21,600
Share Repurchase Program 2012 [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares approved under stock repurchase program (shares)	6,000,000
Common stock shares repurchased during the period (shares)	4,800,000
Common stock shares repurchased during the period (value in US$)	$ 22,200
Remaining number of shares approved under stock repurchase program (shares)	3,500,000