Information Regarding Basic and Diluted Earnings Per Share (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Basic shares used in the calculation of earnings per share	43.8	44.6	44.1	44.8
Diluted shares used in the calculation of earnings per share	44.6	45.2	44.9	45.4
Employee Stock Option
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of securities	0.4	0.2	0.3	0.2
Non-Vested Stock Grants
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of securities	0.4	0.4	0.5	0.4
Segment, Continuing Operations
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Per share effect of dilutive securities on income (loss) from continuing operations and net income (loss)	$ (0.03)	$ (0.02)	$ (0.07)	$ (0.03)