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Cash, Cash Equivalents, and Investments - Additional Information (Detail) (USD $) | 3 Months Ended | 6 Months Ended
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Jun. 29, 2014 | Jun. 30, 2013 | Jun. 29, 2014 | Jun. 30, 2013
Amortized Cost And Fair Value Debt Securities [Abstract] |  |  |  |
Gross realized gains on sale of investments | $ 117,000 | $ 101,000 | $ 629,000 | $ 150,000
Gross realized losses on sale of investments | 12,000 | 49,000 | 23,000 | 67,000
Maximum amount committed to invest in limited partnership |  |  | 20,500,000 |
Contribution to limited partnership | 19,886,000 |  | 19,886,000 |
Remaining amount of commitment in limited partnership | 614,000 |  | 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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- Definition This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563 + Details
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