Pensions - Summary of Components of Net Postretirement Pensions Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
U.S. Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Interest cost	1.8	1.9	5.6	5.8
Amortization of actuarial loss	0.7	1.4	1.9	4.2
Expected return on plan assets	(2.4)	(2.6)	(7.2)	(7.8)
Net postretirement pension expense	0.1	0.7	0.3	2.2
Non-U.S. Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.0	0.0	0.1	0.1
Interest cost	0.3	0.4	1.0	1.4
Amortization of actuarial loss	0.2	0.2	0.5	0.5
Expected return on plan assets	(0.5)	(0.5)	(1.5)	(1.8)
Net postretirement pension expense	$ 0.0	$ 0.1	$ 0.1	$ 0.2