Goodwill and intangible assets (Schedule of indefinite life assets not subject to amortization) (Details) (Tradenames [Member], USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 28, 2014
Tradenames [Member]
Indefinite-lived Intangible Assets [Roll Forward]
Indefinite life assets not subject to amortization, beginning balance	$ 700,592
Currency translation during the year	(6,242)
Indefinite life assets not subject to amortization, ending balance	$ 694,350

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