Segments - Reconciliation of Reportable Segment Adjusted EBITDA to Income Before Income Tax Expense (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Reconciliation of reportable segment Adjusted EBITDA to income before income tax expense:
Total reportable segment Adjusted EBITDA	$ 289.3	$ 271.7	$ 844.2	$ 760.7
Less:
Depreciation expense	51.5	47.7	151.8	142.1
Unallocated general and administrative expenses	2.4	2.0	6.3	6.5
Interest expense, net	51.8	45.8	150.0	131.2
Income before income tax expense	$ 183.6	$ 176.2	$ 536.1	$ 480.9