Leases (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2020
Lease Assets and Liabilities [Abstract]
Operating lease ROU assets		$ 56.2		$ 56.2		$ 61.4
Operating lease ROU assets, Statement of Financial Position [Extensible List]		us-gaap:OtherAssetsNoncurrent		us-gaap:OtherAssetsNoncurrent
Finance lease ROU assets	[1]	$ 8.6		$ 8.6		8.5
Finance lease ROU assets, Statement of Financial Position [Extensible List]		us-gaap:PropertyPlantAndEquipmentNet		us-gaap:PropertyPlantAndEquipmentNet
Operating lease liabilities, current		$ 10.4		$ 10.4		10.9
Operating lease liabilities, current, Statement of Financial Position [Extensible List]		us-gaap:OtherLiabilitiesCurrent		us-gaap:OtherLiabilitiesCurrent
Operating lease liabilities, Other noncurrent liabilities		$ 46.9		$ 46.9		50.3
Operating lease liabilities, noncurrent, Statement of Financial Position [Extensible List]		us-gaap:OtherLiabilitiesNoncurrent		us-gaap:OtherLiabilitiesNoncurrent
Finance lease liabilities, current		$ 0.4		$ 0.4		0.4
Finance lease liabilities, current, Statement of Financial Position [Extensible List]		us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent		us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent
Finance lease liabilities, noncurrent		$ 3.4		$ 3.4		3.3
Finance lease liabilities, noncurrent, Statement of Financial Position [Extensible List]		us-gaap:LongTermDebtAndCapitalLeaseObligations		us-gaap:LongTermDebtAndCapitalLeaseObligations
Accumulated amortization		$ 2.3		$ 2.3		$ 1.8
Components of Lease Expense [Abstract]
Operating lease expense	[2]	4.8	$ 5.4	14.9	$ 15.8
Finance lease expense [Abstract]
Depreciation of ROU assets		0.2	0.2	0.4	0.4
Interest on lease liabilities		0.0	0.0	0.1	0.1
Total lease expense		5.0	5.6	15.4	16.3
Short-term lease expense		$ 0.9	$ 1.0	$ 2.7	$ 2.9

[1] Finance lease right of use (“ROU”) assets were recorded net of accumulated amortization of $2.3 million and $1.8 million as of December 31, 2020 and March 31, 2020, respectively.

[2] For the three and nine months ended December 31, 2020, operating lease expense included short-term lease expense of $0.9 million and $2.7 million, respectively.  For the three and nine months ended December 31, 2019, operating lease expense included short-term lease expense of $1.0 million and $2.9 million, respectively. Variable lease expense was not significant.