Net Income per Share - Share Repurchase Programs (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2016	Oct. 03, 2015	Oct. 01, 2016	Oct. 03, 2015	Mar. 21, 2016	Oct. 23, 2014
Share Repurchase Program
Share repurchase program, amount authorized to be repurchased					$ 20.0	$ 30.0
Number of shares repurchased and retired	110,908	125,000	783,703	388,800
Average repurchase price per share (in dollars per share)	$ 25.84	$ 22.76	$ 24.33	$ 27.83
Amount available for future repurchases	$ 9.0		$ 9.0