Significant Accounting Policies, Short-term investments and Trade Accounts Receivable (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Short-term investments [Abstract]
Short-term investments	$ 5.7	$ 4.7
Trade accounts receivable [Abstract]
Trade receivables, allowance for doubtful accounts	(2.3)	(1.4)
Trade receivables sold without recourse	65.8	55.4	$ 71.3
Loss on the sale of accounts receivables	$ (0.4)	$ (0.3)	$ (0.3)