Income Taxes - Income before income taxes (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Line Items]
United States - Income from Continuing operations before income taxes	$ 87.2	$ 48.9	$ 31.3
Foreign - Income from Continuing operations before income taxes	7.2	40.7	48.5
Income from continuing operations before income taxes	94.4	89.6	79.8
United States federal - provision for income taxes	41.8	34.4	(219.4)
State and local - provision for income taxes	(9.6)	(3.6)	(44.5)
Foreign - provision for income taxes	11.5	6.0	16.7
Provision for (Benefit From) income taxes	43.7	36.8	(247.2)
United States federal - current taxes	2.2	0.9	0.9
State and local - current taxes	2.4	0.8	(4.3)
Foreign - current taxes	10.7	21.7	15.5
Total current income taxes	15.3	23.4	12.1
United States federal - deferred taxes	73.4	60.1	(211.1)
State and local - deferred taxes	(5.2)	(1.3)	(38.4)
Foreign - deferred taxes	3.0	(14.4)	4.4
Total deferred income taxes	71.2	44.4	(245.1)
Tax Benefits from Operating Loss Carryforwards	(42.8)	(31.0)	(14.2)
Provision for (Benefit From) income taxes	43.7	36.8	(247.2)
United States federal [Member]
Income Tax Disclosure [Line Items]
Tax Benefits from Operating Loss Carryforwards	(33.8)	(26.6)	(9.2)
State and Local [Member]
Income Tax Disclosure [Line Items]
Tax Benefits from Operating Loss Carryforwards	(6.8)	(3.1)	(1.8)
Foreign [Member]
Income Tax Disclosure [Line Items]
Tax Benefits from Operating Loss Carryforwards	$ (2.2)	$ (1.3)	$ (3.2)