Derivative Instruments and Hedging Activities - Schedule of Pre-Tax Effect of Derivatives on Unaudited Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Derivative Instruments, Gain (Loss) [Line Items]
Total direct operating expense on consolidated statements of operations	$ 628.2	$ 510.5	$ 983.8	$ 872.5
Total interest expense on consolidated statements of operations	63.0	51.7	121.6	101.6
Forward exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in accumulated other comprehensive income (loss)	0.8	(0.6)	1.0	(3.1)
Gain (loss) reclassified from accumulated other comprehensive (income) loss	(0.2)	(0.4)	(1.2)	0.1
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in accumulated other comprehensive income (loss)	(6.3)	9.3	(2.8)	36.4
Gain (loss) reclassified from accumulated other comprehensive (income) loss	11.4	10.9	22.3	20.1
Loss reclassified from accumulated other comprehensive income (loss) into interest expense	$ (1.5)	$ (1.8)	$ (3.1)	$ (3.8)