Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Income Tax Contingency [Line Items]
Effective tax rate attributable to continuing operations	34.00%	32.10%
unrecognized tax benefits	$ 0
Gross accrued interest and penalties on unrecognized tax benefits	0.4		0.3
Unrecognized income tax benefits that, if recognized, would affect the effective tax rates	6.6		6.5
Unrecognized income tax benefits that, if recognized, would affect the effective tax rates , interest and penalties	$ 0.2		$ 0.2