Basic and Diluted (Loss) Earnings Per Common Share - Components of Basic and Diluted Earnings Per Share (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator:
Income (loss) from continuing operations, net of taxes	$ 9.5	$ (15.0)	$ 27.0	$ 4.2
Income from discontinued operations, net of taxes	0	0	0.3	0.4
Net income	$ 9.5	$ (15.0)	$ 27.3	$ 4.6
Denominator:
Weighted average common shares outstanding - Basic (shares)	52,356,798	52,356,641	52,356,798	52,345,895
Effect of dilutive restricted stock (shares)	0	0	0	11,016
Weighted average common shares outstanding - Diluted (shares)	52,356,798	52,356,641	52,356,798	52,356,911
Income from Continuing Operations, Per Basic Share	$ 0.18	$ (0.29)	$ 0.51	$ 0.08
Income from Discontinued Operations, Net of Tax, Per Basic Share	$ 0.00	$ 0.00	$ 0.01	$ 0.01
Basic earnings per share (usd per share)	$ 0.18	$ (0.29)	$ 0.52	$ 0.09
Income from Continuing Operations, Per Diluted Share	$ 0.18	$ (0.29)	$ 0.51	$ 0.08
Income from Discontinued Operations, Net of Tax, Per Diluted Share	$ 0.00	$ 0.00	$ 0.01	$ 0.01
Diluted earnings per share (usd per share)	$ 0.18	$ (0.29)	$ 0.52	$ 0.09