Segment Information - Revenue, Properties and Outsourcing Assets by Geographic Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 476.8	$ 515.0	$ 993.2	$ 961.7
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	212.2	235.6	413.2	434.6
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	51.6	69.8	173.5	122.7
Other foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 213.0	$ 209.6	$ 406.5	$ 404.4