Components of and Changes in Accumulated Other Comprehensive Income, Net of Related Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 650,672
Other comprehensive (loss) income	(389)	$ 201
Ending Balance	702,742
Unrealized Holding Losses on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(144)
Other comprehensive (loss) income	(730)
Ending Balance	(874)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(3,018)
Other comprehensive (loss) income	341
Ending Balance	(2,677)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(3,162)
Ending Balance	$ (3,551)