Leases (Details) - USD ($) $ in Millions		12 Months Ended
		Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Lease Assets and Liabilities [Abstract]
Operating lease ROU assets		$ 61.4	$ 61.3
Operating lease ROU assets, Statement of Financial Position [Extensible List]		us-gaap:OtherAssetsNoncurrent
Finance lease ROU assets	[1]	$ 8.5
Finance lease ROU assets, Statement of Financial Position [Extensible List]		us-gaap:PropertyPlantAndEquipmentNet
Operating lease liabilities, current		$ 10.9	12.4
Operating lease liabilities, current, Statement of Financial Position [Extensible List]		us-gaap:OtherLiabilitiesCurrent
Operating lease liabilities, noncurrent		$ 50.3	48.9
Operating lease liabilities, noncurrent, Statement of Financial Position [Extensible List]		us-gaap:OtherLiabilitiesNoncurrent
Finance lease liabilities, current		$ 0.4
Finance lease liabilities, current, Statement of Financial Position [Extensible List]		us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent
Finance lease liabilities, noncurrent		$ 3.3
Finance lease liabilities, noncurrent, Statement of Financial Position [Extensible List]		us-gaap:LongTermDebtAndCapitalLeaseObligations
Accumulated amortization		$ 1.8
Components of Lease Expense [Abstract]
Operating lease expense	[2]	21.2
Finance lease expense [Abstract]
Depreciation of ROU assets		0.5
Interest on lease liabilities		0.2
Total lease expense		21.9
Short-term lease expense		4.1
Cash paid for amounts included in measurement of lease liabilities [Abstract]
Operating cash flows for operating leases		14.7
Financing cash flows for finance leases		0.5
ROU assets obtained in exchange for lease liabilities [Abstract]
Operating leases		9.0
Finance leases		$ 0.2
Weighted-average remaining lease term [Abstract]
Operating leases		9 years 3 months 18 days
Finance leases		8 years 9 months 18 days
Weighted-average discount rate [Abstract]
Operating leases		3.50%
Finance leases		4.70%
Maturity of Operating Lease Liabilities [Abstract]
2021		$ 12.8
2022		11.4
2023		9.3
2024		6.3
2025		5.8
2026 and beyond		26.2
Total lease payments		71.8
Less: Interest		(10.6)
Present value of lease liabilities		61.2
Maturities of Finance Lease Liabilities [Abstract]
2021		0.5
2022		0.5
2023		0.5
2024		0.5
2025		0.5
2026 and beyond		2.0
Total lease payments		4.5
Less: Interest		(0.8)
Present value of lease liabilities		$ 3.7
Future minimum rental commitments under non-cancelable operating leases [Abstract]
2020			14.2
2021			12.4
2022			9.1
2023			7.1
2024			4.7
2025 and beyond			22.9
Total future minimum rental commitments			70.4
Rental expense			$ 19.3	$ 18.5
Minimum [Member]
Significant Accounting Policy [Abstract]
Remaining lease term		1 year
Maximum [Member]
Significant Accounting Policy [Abstract]
Remaining lease term		15 years

[1] Finance lease ROU assets were recorded net of accumulated amortization of $1.8 million as of March 31, 2020.

[2] In fiscal 2020, operating lease expense included short-term lease expense of $4.1 million. Variable lease expense was not significant.