Schedule of Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 29, 2019		Dec. 31, 2018
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 502,181	[1]	$ 498,231
Accumulated Amortization	(397,225)	[1]	(367,531)
Foreign Currency Translation Adjustment	(8,383)		(5,218)
Net Carrying Amount	96,573		125,482
Developed technology
Finite-Lived Intangible Assets
Gross Carrying Amount	337,198	[1]	336,308
Accumulated Amortization	(272,317)	[1]	(252,080)
Foreign Currency Translation Adjustment	(6,461)		(4,079)
Net Carrying Amount	58,420		80,149
Customer Relationships
Finite-Lived Intangible Assets
Gross Carrying Amount	100,313	[1]	97,153
Accumulated Amortization	(89,540)	[1]	(83,448)
Foreign Currency Translation Adjustment	(562)		(340)
Net Carrying Amount	10,211		13,365
Trademarks and tradenames
Finite-Lived Intangible Assets
Gross Carrying Amount	64,670	[1]	64,420
Accumulated Amortization	(35,368)	[1]	(31,653)
Foreign Currency Translation Adjustment	(1,360)		(799)
Net Carrying Amount	$ 27,942		31,968
Non-compete Agreements
Finite-Lived Intangible Assets
Gross Carrying Amount			320
Accumulated Amortization			(320)
Backlog
Finite-Lived Intangible Assets
Gross Carrying Amount			30
Accumulated Amortization			$ (30)

[1] $0.7 million of amortizable intangible assets became fully amortized and have been eliminated from the gross carrying amount and accumulated amortization.