Supplemental Disclosure of Cash Flow Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Cash paid during period:
Income taxes			$ 12,217	$ 8,522
Non-cash investing and financing activities:
Unrealized (loss) gain on short-term investments	$ 19	$ (32)	(21)	4
Vested stock unit awards issued to settle accrued bonuses			7,643	6,910
Accrual for capital expenditures			$ 691	$ 135