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Cash, Cash Equivalents, and Investments (Detail) - USD ($) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Oct. 04, 2015 | Sep. 28, 2014 | Oct. 04, 2015 | Sep. 28, 2014
Cash and Cash Equivalents [Abstract] |  |  |  |
Gross realized gains on sale of investments | $ 26,000 | $ 66,000 | $ 434,000 | $ 695,000
Gross realized losses on sale of investments | 7,000 | $ 21,000 | 194,000 | $ 44,000
Maximum amount committed to invest in limited partnership |  |  | 20,500,000 |
Contribution to limited partnership | 19,886,000 |  | $ 19,886,000 |
Investment expiration date |  |  | Dec. 31, 2015 |
Remaining amount of commitment in limited partnership | 614,000 |  | $ 614,000 |
Number of contributions made during the period |  |  | $ 0 |
Distributions from Partnership during period | $ 1,014,000 |  |  |

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