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		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Equity [Abstract]
Translation adjustments - Before Tax Amount	$ 17.6	$ 8.7	$ (5.0)	$ (0.3)
Adjustment for net periodic pension and other postretirement benefits plan cost - Before Tax Amount	9.2	2.0	12.7	3.4
Change in fair value of derivatives - Before Tax Amount		0.1	0.1	0.2
Other comprehensive (loss) income - Before Tax Amount	26.8	10.8	7.8	3.3
Adjustment for net periodic pension and other postretirement benefits plan cost - Income Tax Expense	3.2	0.6	4.5	1.1
Change in fair value of derivatives - Income Tax Expense			0.1	0.1
Other comprehensive (loss) income - Income Tax Expense	3.2	0.6	4.6	1.2
Translation adjustments - Net of Tax Amount	17.6	8.7	(5.0)	(0.3)
Adjustment for net periodic pension and postretirement benefits plan cost	6.0	1.4	8.2	2.3
Change in fair value of derivatives - Net of Tax Amount		0.1		0.1
Other comprehensive income	$ 23.6	$ 10.2	$ 3.2	$ 2.1