Segment Information - Schedule of Reconciliation of Segment General and Administrative Expense to Consolidated (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting, Other Significant Reconciling Item [Line Items]
Segment general and administrative expenses	$ 162.0	$ 171.8	$ 161.7
General and administration	344.6	349.2	387.0
Corporate allocation of share-based compensation	23.9	15.0	26.7
Operating Segments
Segment Reporting, Other Significant Reconciling Item [Line Items]
Segment general and administrative expenses	162.0	171.8	161.7
Corporate
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate general and administrative expenses	120.9	110.6	100.9
Corporate and Reconciling Items
Segment Reporting, Other Significant Reconciling Item [Line Items]
Purchase accounting and related adjustments	12.9	17.1	61.6
General and Administrative Expense
Segment Reporting, Other Significant Reconciling Item [Line Items]
Purchase accounting and related adjustments	8.7	12.0	55.2
General and Administrative Expense | Corporate and Reconciling Items
Segment Reporting, Other Significant Reconciling Item [Line Items]
Share-based compensation expense included in general and administrative expense	53.0	54.8	69.2
Purchase accounting and related adjustments	$ 8.7	$ 12.0	$ 55.2