Reconciliation of Shares Used to Calculate Basic and Diluted Net Income Per Share (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2015	Jul. 04, 2014	Jul. 03, 2015	Jul. 04, 2014
Schedule Of Earnings Per Share Basic and Diluted [Line Items]
Shares used in basic per share computation	26,714	27,040	26,668	27,056
Shares used in diluted per share computation	27,368	27,746	27,386	27,838
Employee Stock Option
Schedule Of Earnings Per Share Basic and Diluted [Line Items]
Effect of dilutive stock outstanding	144	130	143	146
Restricted Stock Units (RSUs)
Schedule Of Earnings Per Share Basic and Diluted [Line Items]
Effect of dilutive stock outstanding	510	576	575	636