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Cash, Cash Equivalents, and Investments - Additional Information (Detail) (USD $) | 3 Months Ended
--- | ---
Mar. 30, 2014 | Mar. 31, 2013
Schedule of Available-for-sale Securities [Line Items] |  |
Gross realized gains on sale of investments | $ 512,000 | $ 50,000
Gross realized losses on sale of investments | 11,000 | 19,000
Maximum amount committed to invest in limited partnership | 20,500,000 |
Contribution to limited partnership | 19,886,000 |
Remaining amount of commitment in limited partnership | 614,000 |
Investment expiration date | Dec. 31, 2015 |
Number of contributions made during the period | 0 |
Distributions From Partnership During Period | $ 0 |

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