Debt - Interest Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Debt Instrument [Line Items]
Debt issuance cost amortization	$ 3.5	$ 4.8
Debt discount amortization	12.6	25.3
Other interest expense	0.7	1.0
Total interest expense	72.3	99.1
Senior Secured Indebtedness
Debt Instrument [Line Items]
Debt issuance cost amortization	2.9	4.1
Debt discount amortization	1.9	1.5
Interest expense	52.7	52.7
Total interest expense	57.5	58.3
Convertible Debt
Debt Instrument [Line Items]
Debt issuance cost amortization	0.6	0.7
Debt discount amortization	10.7	23.8
Interest expense	2.8	15.3
Total interest expense	$ 14.1	$ 39.8