Supplemental Disclosure of Cash Flow Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Sep. 29, 2017	Sep. 30, 2016
Cash paid during period:
Income taxes			$ 17,208	$ 13,375
Non-cash investing and financing activities:
Unrealized gain on short-term investments	$ 13	$ (19)	17	65
Vested stock unit awards issued to settle accrued bonuses			6,910	6,334
Accrual for capital expenditures			$ 162	$ 739