Restructuring (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018	Jun. 30, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1,341	$ 1,029
Impairment of operating lease right-of-use asset (recorded in Restructuring charges)	757	0
June 2017 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,300	$ 1,000
Restructuring and related cost, cost incurred to date	17,700
Minimum | June 2017 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	21,500
Maximum | June 2017 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	$ 23,000
Lease Termination & Fixed Assets | June 2017 Plan
Restructuring Cost and Reserve [Line Items]
Percentage of facility vacated	100.00%
Restructuring charges	$ 1,300
Impairment of operating lease right-of-use asset (recorded in Restructuring charges)	$ (800)
Hyderabad
Restructuring Cost and Reserve [Line Items]
Ownership percentage			100.00%