Related Party Transactions - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jun. 30, 2016	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
RSL and RSI | Services Agreement | RSL and RSI
Related Party Transaction [Line Items]
Allocated costs		$ 4.8	$ 7.7	$ 9.2
RSL | Share-based Compensation Expense Allocated to Company | RSL
Related Party Transaction [Line Items]
Allocated costs		$ 0.6	$ 1.0	$ 4.9
RSL | Option Agreement | RSL
Related Party Transaction [Line Items]
Option agreement, term	2 years
Option agreement, purchase price as a percentage of payments made by RSL	110.00%