Revenues Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Billboard	$ 352.8	$ 360.6	$ 1,014.8	$ 1,062.8
Revenues	467.5	451.9	1,318.4	1,337.7
Static displays
Disaggregation of Revenue [Line Items]
Billboard	231.4	235.6	668.5	701.9
Transit	46.6	44.6	127.1	135.1
Digital displays
Disaggregation of Revenue [Line Items]
Billboard	109.5	111.1	309.0	322.4
Transit	56.0	36.6	141.5	112.4
Other
Disaggregation of Revenue [Line Items]
Billboard	11.9	13.9	37.3	38.5
Transit	9.8	9.7	27.8	26.6
Transit
Disaggregation of Revenue [Line Items]
Transit	112.4	90.9	296.4	274.1
Other Revenues
Disaggregation of Revenue [Line Items]
Transit	$ 2.3	$ 0.4	$ 7.2	$ 0.8