Realignment and reorganization costs Summary (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 28, 2015	Jun. 29, 2014		Jun. 28, 2015	Jun. 29, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 6,279	$ 1,276	[1]	$ 10,892	$ 15,987	[1]
General and Administrative Realignment and Reinvestment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	4,372	0		8,535	0
System Optimization [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 1,907	$ 1,276		$ 2,357	$ 15,987

[1] Previously titled “Facilities action charges (income), net.”