Earnings per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Apr. 01, 2012	Apr. 03, 2011
Net Income
Net income	$ 15.7	$ 11.1
Shares
Shares	36.9	37.5
Per Share Amount
Per Share Amount (in dollars per share)	$ 0.42	$ 0.30
Dilutive securities, principally common stock options
Shares	0.1	0.2
Net Income
Net income	$ 15.7	$ 11.1
Weighted average number of shares:
Weighted average number of shares	37.0	37.7
Per Share Amount
NET INCOME (in dollars per share)	$ 0.42	$ 0.29
Securities not included in the computation of diluted EPS
Options to purchase shares of Class A Common Stock	0.3	0.3