Derivatives (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 01, 2016	Oct. 03, 2015	Oct. 01, 2016	Oct. 03, 2015
Derivative [Line Items]
Net income/(loss)	$ 28,890,000	$ (7,357,000)	$ 65,544,000	$ (596,000)
Commodity Contract [Member]
Derivative [Line Items]
Forward purchase amount	$ 7,700,000		7,700,000
Cash Flow Hedging [Member]
Derivative [Line Items]
Cash flow hedge gain (loss) to be reclassified within 12 months			5,100,000
Net income/(loss)			$ 0