Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Tax Disclosure [Abstract]
Income tax expense	$ (10.2)	$ (5.7)	$ (18.6)	$ (9.9)
Effective tax rate	35.80%	25.10%	35.90%	28.70%
Reduction in unrecognized tax benefits from completion of IRS audit	$ 1.5