| Investments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified | 9 Months Ended | |
|---|---|---|
| Sep. 27, 2014 | Sep. 28, 2013 | |
| Investments Schedule [Abstract] | ||
| Recognized gross realized losses | $ 0 | $ 0 | 
| X | ||||||||||
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- Details 
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| X | ||||||||||
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- Definition This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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