Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			6 Months Ended
	Jun. 28, 2015	Jun. 30, 2014	Jun. 29, 2014	Jun. 28, 2015	Jun. 30, 2014	Jun. 29, 2014	Jul. 27, 2015	Apr. 30, 2013
Net income:
NET INCOME	$ 19.3		$ 21.3	$ 30.9		$ 35.4
Shares
Shares	35,000,000		35,300,000	35,100,000		35,300,000
Per Share Amount
NET INCOME (in dollars per share)	$ 0.55		$ 0.60	$ 0.88		$ 1.00
Dilutive securities, principally common stock options
Common stock equivalents (in shares)	100,000		100,000			100,000
Net Income
Net income	$ 19.3		$ 21.3	$ 30.9		$ 35.4
Weighted average number of shares:
Weighted average number of shares	35,100,000		35,400,000	35,100,000		35,400,000
Per Share Amount
Net income (in dollars per share)	$ 0.55		$ 0.60	$ 0.88		$ 1.00
Securities not included in the computation of diluted EPS
Options to purchase shares of Class A common stock	300,000	300,000		300,000	300,000
Number of shares of the entity's Class A common stock authorized to be repurchased								$ 90.0
Remaining authorized repurchase amount	$ 8.0			$ 8.0
Number of shares of Class A common stock repurchased	185,000		186,000	349,000		347,000
Cost of shares of Class A common stock repurchased	$ 10.1		$ 10.6	$ 19.5		$ 20.0
Subsequent event
Securities not included in the computation of diluted EPS
Number of shares of the entity's Class A common stock authorized to be repurchased							$ 100.0