Income Taxes, Components of Earnings Before Income Taxes and the Provision or Benefit for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Components of earnings (loss) before income taxes [Abstract]
United States	$ 2.5	$ (8.6)	$ (15.4)
Foreign	60.8	29.4	5.5
Earnings (loss) before income taxes	63.3	20.8	(9.9)
Federal [Abstract]
Current	11.6	0.1	0.1
Deferred	23.3	(3.8)	(13.0)
State [Abstract]
Current	(0.3)	0.3	0.2
Deferred	2.0	(0.2)	(2.5)
Foreign [Abstract]
Current	16.1	10.1	9.6
Deferred	(13.2)	(0.6)	(3.3)
Total income tax provision (benefit)	$ 39.5	$ 5.9	$ (8.9)