Stock-Based Compensation (Detail) - Summary Of Changes In Stock Options Outstanding (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Options outstanding	0.3	1.2
Per Share Weighted- Average Exercise Price (in Dollars per share)	$ 11.73	$ 10.93
Weighted Average Remaining Contractual Term	1 year 102 days	1 year 171 days
Aggregate Intrinsic Value (in Dollars)	$ 11.7	$ 27.7
Exercised		(0.9)
Exercised (in Dollars per share)		$ 10.59
Exercised (in Dollars)		$ 25.9