Summary of Impairment Charges (Detail) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Impaired Long-Lived Assets Held and Used [Line Items]
Total Impairment		$ 2,000,000	$ 15,200,000	$ 12,100,000	$ 107,500,000
U.S. Operating Segment
Impaired Long-Lived Assets Held and Used [Line Items]
Theatre properties		1	1.1	4.9	3.6
Theatre operating lease right-of-use assets		1	2.7	4.4	4.7
Total Impairment		2	15	10	106.3
U.S. Operating Segment | Investment in NCMI/NCM
Impaired Long-Lived Assets Held and Used [Line Items]
Investment in NCMI/NCM	[1]	0	11.2	0.7	98
International Operating Segment
Impaired Long-Lived Assets Held and Used [Line Items]
Theatre properties		0	0.1	0.6	0.8
Theatre operating lease right-of-use assets		0	0.1	1.5	0.4
Total Impairment		$ 0	$ 0.2	$ 2.1	$ 1.2

[1] See discussion at Impairment of NCMI Investment in Note 8.