Stockholders' Equity - Summary of Changes in Stockholders' Equity (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 25, 2012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity at beginning of period	$ 324.1	$ 312.6
Net loss	(10.3)	(3.0)
Foreign currency translation	0.1	0
Comprehensive loss	(10.2)	(3.0)
Stock-based compensation	1.9	1.1
Restricted stock units traded for taxes	(0.2)	0
Stockholders' equity at end of period	$ 315.6	$ 310.7