Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014
Net Income Per Common Share [Line Items]
Net income	$ 36.2	$ 32.3	$ 127.7	$ 132.1
Weighted-average shares of common stock outstanding	49.9	50.2	49.8	50.2
Common equivalent shares:
Assumed exercise of dilutive options, restricted shares, restricted stock units and performance share units	0.4	0.8	0.5	0.9
Weighted-average common and common equivalent shares outstanding	50.3	51.0	50.3	51.1
Basic earnings per share	$ 0.72	$ 0.64	$ 2.56	$ 2.63
Diluted earnings per share	$ 0.72	$ 0.63	$ 2.54	$ 2.59
Shares excluded from the determination of potential common stock because inclusion would have been anti-dilutive	1.1	0.4	0.8	0.4