Schedule of Net Pension Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Retirement Benefits [Abstract]
Service costs	$ 2.2	$ 1.4
Interest costs	1.0	1.0
Amortization of actuarial loss	(0.8)	0.0
Settlements	0.0	0.5
Net pension period cost	$ 4.0	$ 2.9