Investments in Affiliates - Summary of Activity for Each of Company's Investments in affiliates (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Schedule Of Equity Method Investments [Line Items]
Cash distributions received	[1]	$ (1.6)	$ 0.0	$ (3.2)	$ (1.5)
Other Affiliates [Member]
Schedule Of Equity Method Investments [Line Items]
Investments, beginning balance				22.6
Cash distributions received				(3.2)
Equity income				4.4
Investments, ending balance		23.8		23.8
AC JV, LLC | Other Affiliates [Member]
Schedule Of Equity Method Investments [Line Items]
Investments, beginning balance				4.2
Cash distributions received				(3.2)
Equity income				2.8
Investments, ending balance		3.8		3.8
Digital Cinema Distribution Coalition | Other Affiliates [Member]
Schedule Of Equity Method Investments [Line Items]
Investments, beginning balance				1.8
Cash distributions received				0.0
Equity income				0.1
Investments, ending balance		1.9		1.9
FE Concepts, LLC | Other Affiliates [Member]
Schedule Of Equity Method Investments [Line Items]
Investments, beginning balance				16.5
Cash distributions received				0.0
Equity income				1.5
Investments, ending balance		18.0		18.0
Other Investment [Member] | Other Affiliates [Member]
Schedule Of Equity Method Investments [Line Items]
Investments, beginning balance				0.1
Cash distributions received				0.0
Equity income				0.0
Investments, ending balance		$ 0.1		$ 0.1

[1] Reflects cash distributions received from equity investees that were recorded as a reduction of the respective investment balances. These distributions are reported entirely within the U.S. operating segment.