Additional Balance Sheet And Cash Flow Information (Marketable Securities) (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Apr. 01, 2012
Restricted Cash and Cash Equivalents Items [Line Items]
Available-for-sale securities	$ 135,246	$ 135,634	$ 134,946
Corporate Bonds [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Available-for-sale securities	$ 135,246	$ 135,634	$ 134,946

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

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