Employee Benefit Plans - Net Pension Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)
Interest cost	$ 2.1	$ 2.2	$ 2.3
Expected return on plan assets	(3.3)	(2.8)	(2.8)
Amortization of net loss	0.9	1.2	1.5
Total net periodic pension (income) expense	$ (0.3)	$ 0.6	$ 1.0