Pensions and Post-Retirement Benefit Plans - Schedule of Change in Funded Status of Pension and Post-Retirement Plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 200.9
Fair value of plan assets at end of year	188.8	$ 200.9
Noncurrent liabilities	46.3	51.6
Accumulated benefit obligation	218.7	243.3
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	243.6	257.5
Service cost	2.0	1.7	$ 2.0
Interest cost	9.0	11.0	10.9
Actuarial losses	7.3	10.7
Settlements	(36.9)	(13.9)
Currency translation	5.5	(9.9)
Benefits paid	(11.4)	(13.5)
Benefit obligation at end of year	219.1	243.6	257.5
Fair value of plan assets at beginning of year	200.9	212.4
Actual return on plan assets	19.5	20.8
Employer contribution	11.2	4.5
Settlements	(36.9)	(13.9)
Currency translation	5.5	(9.4)
Benefits paid	(11.4)	(13.5)
Fair value of plan assets at end of year	188.8	200.9	212.4
Funded status of the plan	(30.3)	(42.7)
Noncurrent assets	7.0	0.8
Current liabilities	1.1	1.1
Noncurrent liabilities	36.2	42.4
Benefit obligation	159.9	238.7
Fair value of plan assets	122.6	195.3
Accumulated benefit obligation	159.6	238.5
Fair value of plan assets	122.6	195.3
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	10.0	9.4
Service cost	0.1	0.1	0.1
Interest cost	0.4	0.4	0.4
Actuarial losses	1.5	1.0
Settlements	0.0	0.0
Currency translation	0.0	0.0
Benefits paid	(0.9)	(0.9)
Benefit obligation at end of year	11.1	10.0	9.4
Fair value of plan assets at beginning of year	0.0	0.0
Actual return on plan assets	0.0	0.0
Employer contribution	0.9	0.9
Settlements	0.0	0.0
Currency translation	0.0	0.0
Benefits paid	(0.9)	(0.9)
Fair value of plan assets at end of year	0.0	0.0	$ 0.0
Funded status of the plan	(11.1)	(10.0)
Noncurrent assets	0.0	0.0
Current liabilities	1.0	0.8
Noncurrent liabilities	$ 10.1	$ 9.2