Goodwill and Acquired Intangibles (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Amortization of acquired intangibles
Cost of product and maintenance	$ 10,071	$ 7,191	$ 26,260	$ 16,758
Amortization of acquired intangibles	6,316	5,141	17,105	14,259
Total amortization of acquired intangibles	$ 16,387	$ 12,332	$ 43,365	$ 31,017

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

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-Section 45

-Paragraph 28

-Subparagraph (b)

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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