Summary Of Significant Accounting Policies (Details) (USD $)	Mar. 31, 2012	Dec. 31, 2011	Mar. 26, 2011	Dec. 25, 2010
Summary Of Significant Accounting Policies [Line Items]
Accounts payable and accrued expenses	$ 57,000,000	$ 50,000,000	$ 54,000,000
Cash and cash equivalents	488,774,000	570,681,000	494,207,000	627,478,000
Outside The United States [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 132,000,000