Restructuring (Details) - USD ($) $ in Thousands	9 Months Ended
	Oct. 01, 2016	Oct. 03, 2015
Restructuring Reserve [Roll Forward]
Balance at beginning of the period	$ 5,078	$ 182
Restructuring charges	8,316	15,780
Costs paid or otherwise settled	(11,280)	(8,257)
Balance at the end of the period	2,114	7,705
Severance and related
Restructuring Reserve [Roll Forward]
Balance at beginning of the period	3,696	0
Restructuring charges	1,863	12,491
Costs paid or otherwise settled	(4,688)	(5,825)
Balance at the end of the period	871	6,666
Lease Termination
Restructuring Reserve [Roll Forward]
Balance at beginning of the period	1,005	43
Restructuring charges	2,343	1,107
Costs paid or otherwise settled	(2,315)	(560)
Balance at the end of the period	1,033	590
Software Contracts & Engineering Tools
Restructuring Reserve [Roll Forward]
Balance at beginning of the period	377	0
Restructuring charges	1,917	2,000
Costs paid or otherwise settled	(2,211)	(1,551)
Balance at the end of the period	83	449
Other
Restructuring Reserve [Roll Forward]
Balance at beginning of the period	0	139
Restructuring charges	2,193	182
Costs paid or otherwise settled	(2,066)	(321)
Balance at the end of the period	$ 127	$ 0