Restructuring (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 28, 2019	Mar. 30, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018	Jun. 30, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 252		$ 90	$ 4,719	$ 5,495
Q2 2019 Sales Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges				2,300
June 2018 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges					4,100
June 2017 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	400		$ 100	2,400	$ 1,400
Restructuring and related cost, cost incurred to date	18,700			18,700
Minimum | June 2017 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	20,000			20,000
Maximum | June 2017 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	21,500			$ 21,500
Lease Termination & Fixed Assets | June 2017 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 300
Percentage of facility vacated		100.00%
Hyderabad
Restructuring Cost and Reserve [Line Items]
Ownership percentage						100.00%