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Cash, Cash Equivalents and Investments - Additional Information (Detail) (USD $) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2012 | Oct. 02, 2011 | Sep. 30, 2012 | Oct. 02, 2011 | Jul. 01, 2012
Schedule of Available-for-sale Securities [Line Items] |  |  |  |  |
Gross realized gains on the sale of investments | $ 342,000 | $ 47,000 | $ 1,669,000 | $ 78,000 |
Gross realized Loss on the sale of investments | 1,000 | 28,000 | 239,000 | 45,000 |
Maximum amount committed to invest in limited partnership |  |  | 20,500,000 |  |
Investment expiration date |  |  | Dec. 31, 2013 |  |
Contribution to limited partnership | 19,886,000 |  | 19,886,000 |  |
Remaining amount of commitment in limited partnership | 614,000 |  | 614,000 |  |
Received a stock distribution |  |  |  |  | 371,000
Recorded a realized loss on stock distribution | 19,000 |  |  |  |
Shares were trading investment were sold | $ 352,000 |  |  |  |

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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=6872113&loc=d3e27357-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 21 -Subparagraph a -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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