Accumulated Other Comprehensive Income - Components of AOCI (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Apr. 01, 2017	Sep. 30, 2017	Sep. 30, 2018
Successor
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign Currency Translation Adjustment	$ (1.5)	$ 1.3		$ 1.8	$ (4.5)
Successor | Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), foreign currency translation adjustment, net of tax, beginning of period					1.4
Foreign Currency Translation Adjustment					(4.5)
Accumulated other comprehensive income (loss), foreign currency translation adjustment, net of tax, end of period	(3.1)				(3.1)
Successor | Total Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign Currency Translation Adjustment					(4.5)
Accumulated other comprehensive income, beginning of period					1.4
Accumulated other comprehensive income (loss), current period change, net of tax					(4.5)
Accumulated other comprehensive income, end of period	$ (3.1)				$ (3.1)
Predecessor
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign Currency Translation Adjustment			$ 5.5