Schedule of Supplemental Information to Condensed Consolidated Statements of Cash Flows (Detail) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2025	Jun. 30, 2024
Schedule Of Cash Flow Supplemental [Line Items]
Cash paid for interest by Holdings	[1]	$ 73.0	$ 76.4
Cash paid for interest by CUSA		62.6	66.0
Cash paid for income taxes, net		19.2	12.8
Noncash investing and financing activities:
Interest expense - NCM (see Note 8)		(10.7)	(11.1)
Change in accounts payable and accrued expenses for the acquisition of theatre properties and equipment	[2]	13.2	0.5
Theatre and other assets acquired under finance leases		1.0	28.0
Investment in NCMI - receipt of common units in NCM (see Note 8)		0.0	0.5
Dividends accrued on unvested performance and restricted stock unit awards		$ 0.4	$ 0.0

[1] Includes the cash interest paid by CUSA.

[2] Additions to theater properties and equipment included in accounts payable as of June 30, 2025 and December 31, 2024 were $20.1 and $6.9, respectively.