Retirement Plans and Other Post-Retirement Benefits - Schedule of Change in Benefit Obligation and Plan Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in Plan Assets
Fair value of plan assets at beginning of year	$ 372.8
Fair value of plan assets at end of year	333.2	$ 372.8
Pension Benefits [Member]
Change in Benefit Obligation
Balance at beginning of year	347.0	311.5
Service cost	2.3	2.0	$ 1.8
Interest cost	13.3	13.7	14.0
Plan amendments	0.1	4.1
Transfers from Discontinued Operations	25.7	27.9
Actuarial (gain)/loss	(10.6)	23.1
Benefits paid	(45.1)	(36.5)
Effect of currency rate changes	(0.5)	1.2
Balance at end of year	332.2	347.0	311.5
Change in Plan Assets
Fair value of plan assets at beginning of year	372.8	327.4
Actual return on plan assets	(22.4)	51.9
Total contributions	2.2	2.1
Related assets transferred from existing pension plan	25.7	27.9
Benefits paid	(45.1)	(36.5)
Fair value of plan assets at end of year	333.2	372.8	327.4
Funded status at end of year	1.0	25.8
Other Benefits [Member]
Change in Benefit Obligation
Balance at beginning of year	9.7	9.2
Service cost	0.1	0.1	0.1
Interest cost	0.5	0.4	0.4
Participant contributions	1.2	1.1
Transfers from Discontinued Operations	4.3	2.5
Actuarial (gain)/loss	(3.1)	(0.6)
Benefits paid	(3.5)	(3.0)
Balance at end of year	9.2	9.7	$ 9.2
Change in Plan Assets
Total contributions	3.5	3.0
Benefits paid	(3.5)	(3.0)
Funded status at end of year	$ (9.2)	$ (9.7)