Employee Benefit Plans - Amounts Included In Consolidated Balance Sheets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Non-current assets	$ 35.9	$ 29.2
Accrued expenses and other liabilities	4.4	4.4
Other non-current liabilities	54.5	53.5
Health Care Benefits
Defined Benefit Plan Disclosure [Line Items]
Non-current assets	0.0	0.0
Accrued expenses and other liabilities	1.0	1.2
Other non-current liabilities	$ 7.8	$ 9.6