Net Income per Share (Details 2) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jul. 04, 2015	Jun. 28, 2014	Jul. 04, 2015	Jun. 28, 2014	Oct. 23, 2014	Feb. 13, 2014	Aug. 10, 2012
Share Repurchase Program
Share repurchase program, amount authorized to be repurchased					$ 30.0	$ 15.0	$ 5.0
Number of shares repurchased and retired	118,900	157,000	263,800	252,600
Average repurchase price per share (in dollars per share)	$ 28.90	$ 21.70	$ 30.23	$ 21.91
Amount available for future repurchases	$ 12.9		$ 12.9