Revenues Revenues - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Contract with Customer, Liability, Revenue Recognized	$ 16.6
Number of Reportable Segments | segment	2
Increase (Decrease) in Contract with Customer, Liability	$ 35.6	$ 4.7	$ (6.9)
Contract With Customer Liability, Noncurrent, Recognition Period	4 years
Revenue, Remaining Performance Obligation, Amount	$ 103.0
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Increase (Decrease) in Contract with Customer, Liability	$ 3.2