Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2016	Oct. 03, 2015	Oct. 01, 2016	Oct. 03, 2015
Earnings Per Share
Net income	$ 20,018	$ 9,975	$ 41,385	$ 23,928
Shares used in computing basic earnings per share (in shares)	41,614	42,331	41,673	42,522
Effect of dilutive securities:
Stock options and other stock-based awards (in shares)	693	464	590	613
Shares used in computing diluted earnings per share (in shares)	42,307	42,795	42,263	43,135
Earnings per share:
Basic (in dollars per share)	$ 0.48	$ 0.24	$ 0.99	$ 0.56
Diluted (in dollars per share)	$ 0.47	$ 0.23	$ 0.98	$ 0.55
Shares excluded from computation of diluted earning per share (in shares)	100	100	200	100