Derivative Instruments And Hedging Activity (Schedule Of Fair Value Of Derivative Instruments By Balance Sheet Location) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 26, 2011
Derivatives, Fair Value [Line Items]
Fair value of derivative instruments, Total derivative assets	$ 1,131	$ 341	$ 5,144
Fair value of derivative instruments, Total derivative liabilities	435	343	331
Derivatives Designated As Hedging Instruments [Member] | Foreign Exchange Contracts [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative instruments, Total derivative liabilities	392
Derivatives Designated As Hedging Instruments [Member] | Foreign Exchange Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative instruments, Total derivative assets		284	633
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange Contracts [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative instruments, Total derivative liabilities	43	92	331
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative instruments, Total derivative assets	341	57
Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts - Fuel [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative instruments, Total derivative liabilities		251
Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts - Fuel [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative instruments, Total derivative assets	$ 790		$ 4,511