Employee Benefit Plans (Net Pension Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
U.S. Plans
Pension expense:
Service cost	$ 0.7	$ 1.4	$ 1.5
Interest cost	4.4	7.3	7.3
Expected return on plan assets	(7.7)	(9.2)	(10.2)
Amortization of prior service cost	0.0	0.0	0.0
Amortization of net loss	2.6	2.5	7.7
Amortization of transition obligation	0.0	0.0	0.0
Curtailment (gain) loss	0.0	0.0	0.0
Settlement loss	0.0	7.4	0.0
Net pension expense	0.0	9.4	6.3
Non-U.S. Plans
Pension expense:
Service cost	3.9	4.2	4.9
Interest cost	3.0	3.7	3.6
Expected return on plan assets	(2.9)	(2.9)	(2.4)
Amortization of prior service cost	0.4	0.7	0.7
Amortization of net loss	1.6	1.3	1.7
Amortization of transition obligation	0.0	0.0	0.1
Curtailment (gain) loss	0.1	(0.2)	0.0
Settlement loss	0.0	0.0	0.9
Net pension expense	$ 6.1	$ 6.8	$ 9.5