Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 30, 2017
Short-term investments:
Marketable equity securities	$ 5,842	$ 4,455
Trading securities held in Non-Qualified Deferred Compensation plan, or NQDC	27,745	31,473
Foreign Currency Contract, Asset, Fair Value Disclosure		2,937
Total Assets	632,407	542,799
Liabilities
Foreign currency exchange contracts	3,908
Money market funds [Member]
Assets
Cash equivalents	598,820	503,934
Fair Value Measurements, Level 1 [Member]
Short-term investments:
Marketable equity securities	5,842	4,455
Trading securities held in Non-Qualified Deferred Compensation plan, or NQDC	27,745	31,473
Foreign Currency Contract, Asset, Fair Value Disclosure		0
Total Assets	632,407	539,862
Liabilities
Foreign currency exchange contracts	0
Fair Value Measurements, Level 1 [Member] \| Money market funds [Member]
Assets
Cash equivalents	598,820	503,934
Fair Value Measurements, Level 2 [Member]
Short-term investments:
Marketable equity securities	0	0
Trading securities held in Non-Qualified Deferred Compensation plan, or NQDC	0	0
Foreign Currency Contract, Asset, Fair Value Disclosure		2,937
Total Assets	0	2,937
Liabilities
Foreign currency exchange contracts	3,908
Fair Value Measurements, Level 2 [Member] \| Money market funds [Member]
Assets
Cash equivalents	0	0
Fair Value Measurements, Level 3 [Member]
Short-term investments:
Marketable equity securities	0	0
Trading securities held in Non-Qualified Deferred Compensation plan, or NQDC	0	0
Foreign Currency Contract, Asset, Fair Value Disclosure		0
Total Assets	0	0
Liabilities
Foreign currency exchange contracts	0
Fair Value Measurements, Level 3 [Member] \| Money market funds [Member]
Assets
Cash equivalents	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Fair value portion of asset contracts related to the exchange of different currencies, including, but not limited to, foreign currency options, forward contracts, and swaps.

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Fair value portion of liability contracts related to the exchange of different currencies, including, but not limited to, foreign currency options, forward (delivery or nondelivery) contracts, and swaps entered into.

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Amount of investments in equity securities and other forms of securities that provide ownership interests expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer.

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