Derivatives (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014 month	Jun. 29, 2013
Derivative [Line Items]
Income / (Loss) activity recognized in other comprehensive loss	$ 1,000,000	$ (1,400,000)	$ (100,000)	$ (3,100,000)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(400,000)	(500,000)	100,000	(1,200,000)
Number of months cash flow hedge gain (loss) reclassified over			12
Net income/ (loss)	34,575,000	26,418,000	(16,431,000)	58,823,000
Cash Flow Hedging [Member]
Derivative [Line Items]
Cash flow hedge gain (loss) to be reclassified within 12 months			(600,000)
Net income/ (loss)			0
Forward Contracts [Member] | Commodity Contract [Member]
Derivative [Line Items]
Forward purchase amount	$ 6,200,000		$ 6,200,000