Long Term Debt - Schedule of carrying values and fair values of debt instruments (Details) - USD ($) $ in Millions		Sep. 30, 2023	Dec. 31, 2022
CNK [Member]
Debt Instrument [Line Items]
Fair value	[1]	$ 2,545.4	$ 2,210.5
CUSA [Member]
Debt Instrument [Line Items]
Fair value		$ 1,873.3	$ 1,771.3

[1] The fair value of the 4.50% convertible senior notes was $672.1 and $439.2 as of September 30, 2023 and December 31, 2022, respectively.