Condensed Consolidated Statements of Income and Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 26, 2017	Sep. 27, 2016	Sep. 26, 2017	Sep. 27, 2016
Condensed Consolidated Statements of Income and Comprehensive Income
Unrealized gain on derivatives, (tax)				$ (18)
Foreign currency translation adjustment, (tax)/benefit	$ (55)	$ (18)	$ (82)	$ 7

Amount of tax expense (benefit), after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, attributable to parent entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=84161450&loc=SL4573702-111684

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4569616-111683

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4569643-111683

Name:	us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToParent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration