Restructuring Charges - Narrative (Details) $ in Millions		3 Months Ended			9 Months Ended
	Jun. 23, 2025 numberOfEmployees	Sep. 30, 2025 USD ($)		Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($)		Sep. 30, 2024 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | numberOfEmployees	120
Restructuring and Related Cost, Number of Positions Eliminated, Period Percent	6.00%
Restructuring charges		$ 0.3	[1]	$ 0.0	$ 20.1	[1]	$ 0.0
Stock-based compensation					23.3		$ 21.8
Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Restructuring charges		0.3
Severance Costs		0.3			17.9
Professional Fees					2.2
Stock-based compensation					2.2
Corporate and Reconciling Items
Restructuring Cost and Reserve [Line Items]
Restructuring charges					8.0
Operating segments | Billboard Operating Segment
Restructuring Cost and Reserve [Line Items]
Restructuring charges		0.2			8.4
Operating segments | Transit Operating Segment
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 0.1			$ 3.7

[1] In the three and nine months ended September 30, 2025, Restructuring charges associated with the Plan, consists of severance payments, employee benefits and related costs, and professional fees, and includes approximately $2.2 million in non-cash charges for stock-based compensation