Components of and Changes in Accumulated Other Comprehensive Income, Net of Related Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			$ 686,824
Other comprehensive income (loss)	$ 1,381	$ (1,733)	2,930	$ (2,122)
Ending Balance	728,300		728,300
Unrealized Holding (Losses) Gains on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(930)
Other comprehensive income (loss)			1,805
Ending Balance	875		875
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(4,945)
Other comprehensive income (loss)			1,125
Ending Balance	(3,820)		(3,820)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(5,875)
Ending Balance	$ (2,945)		$ (2,945)