Employee Benefit Plans - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined benefit pension plan, liabilities	$ 70.0	$ 72.7
Defined benefit pension plan liabilities, current	1.3	1.3
Defined benefit pension plan, liabilities, noncurrent	68.7	71.4
Net periodic pension cost for fiscal 2021	$ 2.8
Percentage of employee's base salary allowed as employee contribution (in hundredths)	60.00%
Amount of company contributions	$ 5.3	8.6	$ 8.8
Maximum
Defined Benefit Plan Disclosure [Line Items]
Termination benefits, salary period	5 months
Management incentive compensation plan
Defined Benefit Plan Disclosure [Line Items]
Compensation expense charged against operations	$ 28.3	18.7	48.1
Cash bonus plan
Defined Benefit Plan Disclosure [Line Items]
Compensation expense charged against operations	$ 23.8	$ 16.4	$ 36.3