Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jul. 01, 2014	Jun. 30, 2015	Jul. 01, 2014
Net income per share
Antidilutive securities excluded from calculation of basic earnings per share (in shares)	600	400	1,100	800
Net income per share, basic and diluted
Net income	$ 34,724	$ 30,049	$ 63,147	$ 52,567
Basic weighted average shares outstanding (in shares)	48,451	49,349	48,838	50,044
Dilutive effect of equity awards (in shares)	1,811	2,009	1,843	2,054
Diluted weighted average shares outstanding (in shares)	50,262	51,358	50,681	52,098
Basic net income per share (in dollars per share)	$ 0.72	$ 0.61	$ 1.29	$ 1.05
Diluted net income per share (in dollars per share)	$ 0.69	$ 0.59	$ 1.25	$ 1.01
Restricted stock
Net income per share
Antidilutive securities excluded from calculation of basic earnings per share (in shares)			1,800	1,800