Debt - Debt and Average Interest Rates on Debt Outstanding (Detail) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Jun. 30, 2022
Debt Instrument [Line Items]
Debt, gross	$ 2,102.0
Unamortized debt issuance costs and discounts	(17.7)	$ (18.5)
Total debt	2,084.3	1,988.3
Line of Credit | Term Loans Due 2024
Debt Instrument [Line Items]
Debt, gross	$ 200.0
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Average interest rate as of March 31, 2024	6.542%
Debt, gross	$ 101.4	0.0
Term Loans | 5-year Term Loan Facility
Debt Instrument [Line Items]
Average interest rate as of March 31, 2024	6.785%
Debt, gross	$ 981.3	987.5	$ 1,000.0
Term Loans | Term Loans, 1.033% due in 2024
Debt Instrument [Line Items]
Average interest rate as of March 31, 2024	6.55%
Debt, gross	$ 200.0	200.0
Senior Notes | Senior Notes 4.650% Due 2025
Debt Instrument [Line Items]
Average interest rate as of March 31, 2024	4.65%
Debt, gross	$ 19.3	19.3
Senior Notes | Senior Notes 4.500% Due 2029
Debt Instrument [Line Items]
Average interest rate as of March 31, 2024	4.50%
Debt, gross	$ 400.0	400.0
Senior Notes | Senior Notes Five Point Nine Percent Due Twenty Thirty Two
Debt Instrument [Line Items]
Average interest rate as of March 31, 2024	5.90%
Debt, gross	$ 400.0	$ 400.0