Stock Plans (Summary of Stock Option Activity) (Details) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Apr. 02, 2017 USD ($) $ / shares shares
Stock option activity
Number of Shares, Outstanding at beginning of period | shares	2,287
Number of Shares, Granted | shares	446
Number of Shares, Exercised | shares	(140)
Number of Shares, Outstanding at end of period | shares	2,593
Number of Shares, Exercisable at end of period | shares	1,611
Weighted-Average Price, Outstanding at beginning of period | $ / shares	$ 37.64
Weighted-Average Price, Granted | $ / shares	53.45
Weighted-Average Price, Exercised | $ / shares	33.09
Weighted-Average Price, Outstanding at end of period | $ / shares	40.60
Weighted-Average Price, Exercisable at end of period | $ / shares	$ 35.48
Weighted-Average Remaining Contractual Term in Years, Outstanding at end of period	4 years 2 months
Weighted-Average Remaining Contractual Term in Years, Exercisable at end of period	3 years 1 month
Total Intrinsic Value, Outstanding at end of period | $	$ 36.1
Total Intrinsic Value, Exercisable at end of period | $	$ 30.7