Goodwill and intangible assets - Schedule of indefinite life assets not subject to amortization (Details) - Tradenames [Member] $ in Thousands	6 Months Ended
Jul. 02, 2016 USD ($)
Indefinite-lived Intangible Assets [Roll Forward]
Indefinite life assets not subject to amortization, beginning balance	$ 632,349
Currency translation during the period	11,413
Indefinite life assets not subject to amortization, ending balance	$ 643,762

Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

Name:	us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant