Financial Instruments And Derivatives (Schedule Of Reported Financial Assets And Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Apr. 01, 2012	Dec. 31, 2011
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	$ 570,823	$ 593,402
Contingent consideration	61,210	68,892
Liabilities	61,210	69,206
Cash And Cash Equivalents [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	361,942	412,493
Marketable Securities [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	87,223	96,502
Long-Term Marketable Securities [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	121,512	84,407
Prepayments And Other Current Assets [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	146
Other Accrued Liabilities [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Liabilities		314
Level 1 [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	383,593	419,020
Contingent consideration
Liabilities
Level 1 [Member] | Cash And Cash Equivalents [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	350,544	396,329
Level 1 [Member] | Marketable Securities [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	4,011	9,044
Level 1 [Member] | Long-Term Marketable Securities [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	29,038	13,647
Level 1 [Member] | Prepayments And Other Current Assets [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets
Level 1 [Member] | Other Accrued Liabilities [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Liabilities
Level 2 [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	187,230	174,382
Contingent consideration
Liabilities		314
Level 2 [Member] | Cash And Cash Equivalents [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	11,398	16,164
Level 2 [Member] | Marketable Securities [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	83,212	87,458
Level 2 [Member] | Long-Term Marketable Securities [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	92,474	70,760
Level 2 [Member] | Prepayments And Other Current Assets [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets	146
Level 2 [Member] | Other Accrued Liabilities [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Liabilities		314
Level 3 [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets
Contingent consideration	61,210	68,892
Liabilities	61,210	68,892
Level 3 [Member] | Cash And Cash Equivalents [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets
Level 3 [Member] | Marketable Securities [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets
Level 3 [Member] | Long-Term Marketable Securities [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets
Level 3 [Member] | Prepayments And Other Current Assets [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Assets
Level 3 [Member] | Other Accrued Liabilities [Member]
Fair Value Of Assets And Liabilities Measured On A Recurring Basis [Line Items]
Liabilities