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]
Effective tax rate for income from continuing operations	33.60%	31.30%	35.10%	38.20%
Discrete tax charges		$ 1.0		$ 1.0