Income Taxes - Carryforwards (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Interest limitation carry forwards	$ 105.8	$ 0.0
R&D and state credit carry forwards	29.1	$ 26.7
Federal
Operating Loss Carryforwards [Line Items]
NOL carry forwards	1,540.3
Interest limitation carry forwards	413.9
R&D and state credit carry forwards	29.1
State
Operating Loss Carryforwards [Line Items]
NOL carry forwards	1,437.2
Interest limitation carry forwards	252.6
R&D and state credit carry forwards	2.4
Foreign
Operating Loss Carryforwards [Line Items]
NOL carry forwards	164.7
Interest limitation carry forwards	7.4
R&D and state credit carry forwards	$ 0.0