Reconciles the Denominators of the Company's Calculation for Basic and Diluted Net Income per Share (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Oct. 02, 2020	Sep. 27, 2019	Oct. 02, 2020	Sep. 27, 2019
Schedule Of Earnings Per Share Basic and Diluted [Line Items]
Shares used in basic per share computation	52,316	52,802	52,383	52,694
Shares used in diluted per share computation	53,209	54,002	53,342	53,906
Employee Stock Option
Schedule Of Earnings Per Share Basic and Diluted [Line Items]
Effect of dilutive stock outstanding	331	491	351	475
Restricted Stock Units (RSUs)
Schedule Of Earnings Per Share Basic and Diluted [Line Items]
Effect of dilutive stock outstanding	562	709	608	737