Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017
Basic net income per share:
Net income	$ 207,289	$ 160,649	$ 278,722	$ 220,960
Weighted average number of shares outstanding, basic	122,100	128,186	123,288	129,231
Net income per share – basic	$ 1.70	$ 1.25	$ 2.26	$ 1.71
Diluted net income per share:
Dilutive stock options and restricted stock units outstanding, income	$ 0	$ 0	$ 0	$ 0
Dilutive stock options and restricted stock units outstanding, per share (in shares)	675	536	687	675
Dilutive stock options and restricted stock units outstanding, per share (in dollars per share)	$ (0.01)	$ (0.00)	$ (0.01)	$ (0.01)
Net income	$ 207,289	$ 160,649	$ 278,722	$ 220,960
Weighted average number of shares outstanding, diluted	122,775	128,722	123,975	129,906
Net income per share, diluted (in dollars per share)	$ 1.69	$ 1.25	$ 2.25	$ 1.70
Antidilutive securities excluded from computation of earnings per share, amount	3,800	4,100	3,700	3,200