(Out of Period Adjustment) (Details) - USD ($) $ in Millions	2 Months Ended	3 Months Ended			9 Months Ended	12 Months Ended
	Jun. 03, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Successor Company
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Prior period reclassification adjustment		$ 1.3
Predecessor Company
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Prior period reclassification adjustment	$ 1.9		$ 3.1	$ 1.6	$ 3.7	$ 6.2	$ 4.3