Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income taxes computed at Federal statutory rate	$ (23.9)	$ (15.3)	$ 1.1
Foreign operations subject to different income tax rates	6.9	6.8	5.0
State income tax	(1.5)	5.9	(0.6)
Remeasurements of originating deferred tax assets and liabilities	(283.4)	4.7	(4.7)
Permanent differences	2.1	0.1	2.1
Nondeductible share based compensation	4.5	1.2	1.8
Nondeductible officers compensation	4.2	7.7	9.8
Non-controlling interest in partnerships	2.8	18.6	1.8
Foreign derived intangible income	0.0	(2.4)	(1.4)
Other	0.1	2.7	1.7
Changes in valuation allowance	302.7	4.2	(2.3)
Total provision for income taxes	$ 14.5	$ 34.2	$ 14.3