Post Retirement Benefit Plans - Changes in Benefit Obligations and Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in benefit obligation:
Benefit obligation at beginning of year	$ 228.0	$ 210.1
Service cost	7.5	7.8	$ 6.8
Interest cost	2.0	1.7	2.2
Plan participant contributions	4.3	4.1
Plan amendments	(1.3)
Plan settlements	(0.4)
Benefits paid	(2.0)	(3.6)
Actuarial loss (gain)	(16.2)	(3.6)
Premiums paid	(1.7)	(1.5)
Impact of foreign currency exchange rates	(3.5)	13.0
Benefit obligation at end of year	216.7	228.0	210.1
Change in plan assets:
Fair value of plan assets at beginning of year	120.3	105.9
Return on plan assets	(0.6)	5.0
Plan participant and employer contributions	10.2	9.5
Benefits paid	(2.2)	(3.6)
Plan settlements	(0.4)
Premiums paid	(1.5)	(1.5)
Impact of foreign currency exchange rates	(1.2)	5.0
Fair value of plan assets at end of year	124.6	120.3	105.9
Net under funded status	(92.1)	(107.7)
Interest and other income (expense), net	(17.7)	(21.7)	(4.2)
Accumulated benefit obligation	$ 206.9	217.2
ASU 2017-07, Compensation-Retirement Benefits | Reclassification for retrospective adoption
Change in plan assets:
Cost of sales, selling, general and administrative, and research and development expense		(4.8)	(4.6)
Interest and other income (expense), net		$ 4.8	$ 4.6