Schedule of Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands		6 Months Ended		12 Months Ended
		Jul. 01, 2018		Dec. 31, 2017
Finite-Lived Intangible Assets
Gross Carrying Amount		$ 505,688	[1],[2]	$ 414,038
Accumulated Amortization		(354,273)	[1]	(337,155)
Foreign Currency Translation Adjustment		(3,242)		2,205
Net Carrying Amount		148,173		79,088
Developed technology
Finite-Lived Intangible Assets
Gross Carrying Amount		341,227	[1],[2]	270,877
Accumulated Amortization		(236,924)	[1]	(226,190)
Foreign Currency Translation Adjustment		(2,687)		1,618
Net Carrying Amount		101,616		46,305
Customer Relationships
Finite-Lived Intangible Assets
Gross Carrying Amount		100,891	[1],[2]	92,741
Accumulated Amortization		(86,509)	[1]	(83,585)
Foreign Currency Translation Adjustment		(118)		171
Net Carrying Amount		14,264		9,327
Trademarks and tradenames
Finite-Lived Intangible Assets
Gross Carrying Amount		63,240	[1],[2]	50,100
Accumulated Amortization		(30,530)	[1]	(27,120)
Foreign Currency Translation Adjustment		(437)		416
Net Carrying Amount		32,273		23,396
Non-compete Agreements
Finite-Lived Intangible Assets
Gross Carrying Amount		320	[1],[2]	320
Accumulated Amortization		(300)	[1]	(260)
Net Carrying Amount		20		$ 60
Customer backlog
Finite-Lived Intangible Assets
Gross Carrying Amount	[1],[2]	10
Accumulated Amortization	[1]	$ (10)

[1] In 2018, $0.3 million of amortizable intangible assets became fully amortized and have been eliminated from the gross carrying amount and accumulated amortization.

[2] Includes intangible assets acquired in 2018, $79.7 million from the MiR acquisition and $12.3 million from the Energid acquisition.