Other expense (income) (Summary of other expense (income)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014	Jun. 29, 2013
Component Of Other Expense (Income) Nonoperating [Line Items]
Total other expense (income)	$ (1,555)	$ (1,097)	$ 3,335	$ 5,290
Foreign Currency (Gains) Losses, Net [Member]
Component Of Other Expense (Income) Nonoperating [Line Items]
Total other expense (income)	(1,033)	(767)	4,855	3,032
All Other, Net [Member]
Component Of Other Expense (Income) Nonoperating [Line Items]
Total other expense (income)	$ (522)	$ (330)	$ (1,520)	$ 2,258