Comprehensive Income - Schedule of Components of Other Comprehensive (loss) Income and Income Tax Expense Allocated to Each Component (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Equity [Abstract]
Translation adjustments - Before Tax Amount	$ (37.5)	$ (15.0)	$ (42.5)	$ (15.3)
Adjustment for net periodic pension and other postretirement benefits plan cost - Before Tax Amount	3.4	1.4	16.1	4.8
Change in fair value of derivatives - Before Tax Amount			0.1	0.2
Other comprehensive (loss) income - Before Tax Amount	(34.1)	(13.6)	(26.3)	(10.3)
Adjustment for net periodic pension and other postretirement benefits plan cost - Income Tax Expense	1.2	0.4	5.7	1.5
Change in fair value of derivatives - Income Tax Expense	(0.1)			0.1
Other comprehensive (loss) income - Income Tax Expense	1.1	0.4	5.7	1.6
Translation adjustments - Net of Tax Amount	(37.5)	(15.0)	(42.5)	(15.3)
Adjustment for net periodic pension and other postretirement benefits plan cost - Net of Tax Amount	2.2	1.0	10.4	3.3
Change in fair value of derivatives - Net of Tax Amount	0.1		0.1	0.1
Other comprehensive loss	$ (35.2)	$ (14.0)	$ (32.0)	$ (11.9)