Restructuring (Schedule of Restructuring Activities) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Restructuring Reserve [Roll Forward]
Balance at beginning of the period	$ 10,680	$ 2,447
Restructuring charges	1,341	1,029
Costs paid or otherwise settled	(3,508)	(1,724)
Balance at the end of the period	8,513	1,752
Severance & related
Restructuring Reserve [Roll Forward]
Balance at beginning of the period	1,814	1,192
Restructuring charges	(60)	241
Costs paid or otherwise settled	(1,540)	(908)
Balance at the end of the period	214	525
Lease Termination & Fixed Assets
Restructuring Reserve [Roll Forward]
Balance at beginning of the period	8,630	870
Restructuring charges	1,409	13
Costs paid or otherwise settled	(1,875)	(85)
Balance at the end of the period	8,164	798
Software Contracts & Engineering Tools
Restructuring Reserve [Roll Forward]
Balance at beginning of the period	218	360
Restructuring charges	0	738
Costs paid or otherwise settled	(83)	(700)
Balance at the end of the period	135	398
Other
Restructuring Reserve [Roll Forward]
Balance at beginning of the period	18	25
Restructuring charges	(8)	37
Costs paid or otherwise settled	(10)	(31)
Balance at the end of the period	$ 0	$ 31