Reconciliation of Shares Used to Calculate Basic and Diluted Net Income Per Share (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Oct. 02, 2015	Oct. 03, 2014	Oct. 02, 2015	Oct. 03, 2014
Schedule Of Earnings Per Share Basic and Diluted [Line Items]
Shares used in basic per share computation	26,597	26,938	26,644	27,018
Shares used in diluted per share computation	27,268	27,648	27,350	27,778
Employee Stock Option
Schedule Of Earnings Per Share Basic and Diluted [Line Items]
Effect of dilutive stock outstanding	139	118	143	138
Restricted Stock Units (RSUs)
Schedule Of Earnings Per Share Basic and Diluted [Line Items]
Effect of dilutive stock outstanding	532	592	563	622