Consolidated Statement Of Shareholders' Equity (Deficit) (USD $) In Millions, unless otherwise specified	Total	Class A Common Shares [Member]	Class B Common Shares [Member]	Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2012	$ 136.5	$ 0	$ 0	$ 2,209.1	$ (2,073.0)	$ 0.4
Shareholders' Equity (Deficit) [Roll Forward]
Equity-based compensation expense	1.9	0	0	1.9	0	0
Treasury Stock, Value, Acquired, Cost Method	0.1	0	0	0	0.1	0
Accrued charitable contribution related to the MPK Coworker Incentive Plan II, net of tax	(0.3)	0	0	(0.3)	0	0
MPK Coworker Incentive Plan II units withheld for taxes	(0.1)	0	0	(0.1)	0	0
Net income (loss)	28.3	0	0	0	28.3	0
Foreign currency translation adjustment	(2.4)	0	0	0	0	(2.4)
Balance at Mar. 31, 2013	$ 163.8	$ 0	$ 0	$ 2,210.6	$ (2,044.8)	$ (2.0)