Restructuring (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1,576	$ 2,568	$ 1,642	$ 7,999
March 2015 Plan and September 2015 Reduction
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(800)		(800)
March 2015 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(400)	2,400	(100)	5,900
Restructuring and related cost, cost incurred to date	20,500		20,500
Restructuring and related cost, expected cost	21,000		21,000
September 2015 Reduction
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(500)	$ 200	(700)	$ 2,100
Restructuring and related cost, cost incurred to date	7,200		7,200
Restructuring and related cost, expected cost	8,000		8,000
June 2017 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cost incurred to date	2,400		2,400
Minimum | June 2017 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	8,000		8,000
Maximum | June 2017 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	$ 19,000		$ 19,000