Acquisitions - Pro Forma Effect on Operating Results (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 27, 2015	Sep. 28, 2014	Sep. 27, 2015	Sep. 28, 2014
Tripwire [Member]
Business Acquisition [Line Items]
Revenues	$ 588,986	$ 638,353	$ 1,751,090	$ 1,760,018
Income (loss) from continuing operations	$ 21,032	$ 20,855	$ 38,763	$ 12,250
Diluted income (loss) per share from continuing operations	$ 0.49	$ 0.47	$ 0.90	$ 0.28
Grass Valley and Prosoft [Member]
Business Acquisition [Line Items]
Revenues		$ 612,617		$ 1,790,876
Income (loss) from continuing operations		$ 36,036		$ 49,645
Diluted income (loss) per share from continuing operations		$ 0.82		$ 1.12

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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- Definition

The pro forma income from continuing operations before changes in accounting and extraordinary items, net of tax effect, per diluted share of common stock for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(2)-(3)

-URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1392-128463

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- Definition

The pro forma income from continuing operations before changes in accounting and extraordinary items, net of tax effect, for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

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- Definition

The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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