Other expense (income) (Summary of other expense (income)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jul. 02, 2011	Jun. 30, 2012	Jul. 02, 2011
Component Of Other Expense (Income) Nonoperating [Line Items]
Total other expense (income)	$ 440	$ 396	$ (1,385)	$ 381
Foreign Currency (Gains) Losses, Net [Member]
Component Of Other Expense (Income) Nonoperating [Line Items]
Total other expense (income)	(1,052)	1,199	(6,702)	(1,783)
All Other, Net [Member]
Component Of Other Expense (Income) Nonoperating [Line Items]
Total other expense (income)	$ 1,492	$ (803)	$ 5,317	$ 2,164