Derivatives (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 25, 2011	Sep. 30, 2012	Sep. 25, 2011	Sep. 25, 2011 Interest rate swap	Sep. 30, 2012 First credit facility with KeyBank	Nov. 14, 2011 First credit facility with KeyBank	Jul. 27, 2011 First credit facility with KeyBank	Mar. 31, 2008 First credit facility with KeyBank
Line of Credit Facility [Line Items]
Maximum borrowing capacity						$ 110.0	$ 90.0	$ 65.0	$ 85.0
Other income, net	$ 0.4	$ (0.3)	$ 1.3	$ 0	$ 0.3