Additional Balance Sheet And Cash Flow Information (Marketable Securities) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 25, 2011
Restricted Cash and Cash Equivalents Items [Line Items]
Available-for-sale securities	$ 136,376	$ 153,380	$ 179,285
U.S. Treasuries [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Available-for-sale securities	0	0	0
Corporate Bonds [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Available-for-sale securities	$ 136,376	$ 153,380	$ 179,285

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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+ Details