Components of and Changes in Accumulated Other Comprehensive Income, Net of Related Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			$ 691,835
Other comprehensive (loss) gain	$ (1,087)	$ 1,181	(940)	$ (3,752)
Ending Balance	899,690		899,690
Unrealized Holding Gains (Losses) on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			2,808
Other comprehensive (loss) gain			(1,260)
Ending Balance	1,548		1,548
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(4,807)
Other comprehensive (loss) gain			320
Ending Balance	(4,487)		(4,487)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(1,999)
Other comprehensive (loss) gain			(940)
Ending Balance	$ (2,939)		$ (2,939)