Goodwill and Other Intangible Assets - Schedule of Identifiable Intangible Assets Other Than Goodwill (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Net Carrying Amount	$ 6.9
Other Noncurrent Assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	11.9	$ 11.9
Accumulated Amortization	5.0	4.7
Net Carrying Amount	6.9	7.2
Other Noncurrent Assets | Customer lists
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	10.5	10.5
Accumulated Amortization	3.7	3.5
Net Carrying Amount	6.8	7.0
Other Noncurrent Assets | Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1.4	1.4
Accumulated Amortization	1.3	1.2
Net Carrying Amount	$ 0.1	$ 0.2