Pension Plans Components of Net Periodic Pension Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
United States Pension Plan of US Entity [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0.0
Interest cost	0.3
Expected return on plan assets	(0.3)
Amortization of net loss	0.0
Net curtailment and settlement loss recognized	0.0
Net periodic pension cost	0.0
Foreign Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4.0	$ 3.5
Interest cost	5.9	7.4
Expected return on plan assets	(7.4)	(8.1)
Amortization of net loss	4.6	5.3
Net curtailment and settlement loss recognized	0.9	0.2
Net periodic pension cost	$ 8.0	$ 8.3