Income Taxes - Reconciliation of Tax Expense to Statutory Federal Income Tax Rate (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliation Of Tax Expense To Statutory Rate [Line Items]
Computed expected tax expense	$ 33.0	$ 31.4	$ 27.9
State and local taxes, net of U.S. federal income tax benefit	4.0	(2.4)	(0.1)
Foreign and U.S. tax effects attributable to operations outside the U.S.	(3.8)	3.8	(5.1)
Reduction in valuation allowance	(15.8)	(16.9)	(292.2)
Foreign dividends and earnings taxable in the U.S.	12.7	15.2	14.5
Restructuring charges and litigation loss contingency for which there is no tax benefit	11.1
Other	2.5	5.7	7.8
Provision for (Benefit From) income taxes	$ 43.7	$ 36.8	$ (247.2)