Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - Fair Value Measurements, Recurring - USD ($) $ in Millions		Sep. 30, 2024	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment in NCMI	[1]	$ 30.8	$ 18.1
Interest rate swap assets	[2]	2.0	9.9
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment in NCMI	[1]	30.8	0.0
Interest rate swap assets	[2]	0.0	0.0
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment in NCMI	[1]	0.0	18.1
Interest rate swap assets	[2]	2.0	9.9
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment in NCMI	[1]	0.0	0.0
Interest rate swap assets	[2]	$ 0.0	$ 0.0

[1] See further discussion of investment in NCMI at Note 8.

[2] See further discussion of interest rate swaps at Note 7.