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, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive income, Before Tax Amount	$ (11.6)	$ 26.8	$ 11.5	$ 7.8
Other comprehensive income, Income Tax Expense	4.2	3.2	10.0	4.6
Other comprehensive income, Net of Tax Amount	(15.8)	23.6	1.5	3.2
Translation adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive income, Before Tax Amount	(22.5)	17.6	(4.6)	(5.0)
Other comprehensive income, Income Tax Expense	0.0	0.0	0.0	0.0
Other comprehensive income, Net of Tax Amount	(22.5)	17.6	(4.6)	(5.0)
Adjustment for net periodic pension and other postretirement benefits plan cost
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive income, Before Tax Amount	10.9	9.2	16.1	12.7
Other comprehensive income, Income Tax Expense	4.2	3.2	10.0	4.5
Other comprehensive income, Net of Tax Amount	$ 6.7	6.0	$ 6.1	8.2
Change in fair value of derivatives
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive income, Before Tax Amount		0.0		0.1
Other comprehensive income, Income Tax Expense		0.0		0.1
Other comprehensive income, Net of Tax Amount		$ 0.0		$ 0.0