Other Investments- Summary of Activity for Each of Company's Other Investments (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Schedule Of Equity Method Investments [Line Items]
Investments, beginning balance	$ 25.2
Cash distributions received	(1.5)	$ (0.2)
Equity income	(7.5)	$ (22.1)
Investments, ending balance	26.3
AC JV, LLC
Schedule Of Equity Method Investments [Line Items]
Investments, beginning balance	3.7
Cash distributions received	(1.5)
Equity income	1.6
Other	0.0
Investments, ending balance	3.8
Digital Cinema Distribution Coalition
Schedule Of Equity Method Investments [Line Items]
Investments, beginning balance	25.2
Cash distributions received	(1.5)
Equity income	2.8
Other	(0.2)
Investments, ending balance	26.3
Other Affiliates | Digital Cinema Distribution Coalition
Schedule Of Equity Method Investments [Line Items]
Investments, beginning balance	1.8
Cash distributions received	0.0
Equity income	0.1
Other	0.0
Investments, ending balance	1.9
Other Affiliates | FE Concepts, LLC
Schedule Of Equity Method Investments [Line Items]
Investments, beginning balance	19.3
Cash distributions received	0.0
Equity income	1.1
Other	0.0
Investments, ending balance	20.4
Other Affiliates | Other Investments
Schedule Of Equity Method Investments [Line Items]
Investments, beginning balance	0.4
Cash distributions received	0.0
Equity income	0.0
Other	(0.2)
Investments, ending balance	$ 0.2