Stock Based Compensation - Components of Equity-Based Compensation (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Feb. 07, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Compensation Expense (4)	$ 11.7	$ 9.7	$ 3.6	$ 38.6	$ 7.9
Total Expected Tax Benefit	2.8	6.3	0.0	6.3	0.0
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Compensation Expense (4)	0.0	1.7	0.0	21.7	0.0
Total Expected Tax Benefit	0.0	5.6	0.0	5.6	0.0
Restricted Stock & RSU's
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Compensation Expense (4)	11.7	1.0	0.0	1.0	0.0
Total Expected Tax Benefit	2.8	0.7	0.0	0.7	0.0
Incentive Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Compensation Expense (4)	0.0	7.0	3.6	15.9	7.9
Total Expected Tax Benefit	$ 0.0	$ 0.0	$ 0.0	$ 0.0	$ 0.0