Short-Term Investments (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 30, 2012	Dec. 25, 2011
Schedule of Held-to-maturity Securities [Line Items]
Minimum original maturity date of short-term investments	3 months
Carrying value of short-term investments	$ 134,820	$ 104,846
Minimum [Member]
Schedule of Held-to-maturity Securities [Line Items]
Term of short-term investments	11 days
Maximum [Member]
Schedule of Held-to-maturity Securities [Line Items]
Term of short-term investments	7 months
US Treasury Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Carrying value of short-term investments	124,800	104,800
Commercial Paper [Member]
Schedule of Held-to-maturity Securities [Line Items]
Carrying value of short-term investments	$ 10,000