Business Acquisitions and Divestiture - WIL Laboratories, Pro Forma Financial Information (Details) - WIL Research - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 25, 2016	Jun. 25, 2016
Business Acquisition [Line Items]
Revenue	$ 434,917	$ 849,455
Net income attributable to common shareholders	$ 44,159	$ 89,222
Earnings per common share
Basic (in dollars per share)	$ 0.94	$ 1.90
Diluted (in dollars per share)	$ 0.92	$ 1.87

Business Acquisition, Pro Forma Earnings Per Share [Abstract]

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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.

+ References

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The pro forma basic net income per share 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=79982066&loc=d3e1392-128463

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The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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

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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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