Segment Information - Revenue, Properties and Outsourcing Assets by Geographic Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 515.0	$ 517.3	$ 961.7	$ 1,027.1
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	235.6	201.6	434.6	436.1
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	69.8	104.1	122.7	172.1
Other foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 209.6	$ 211.6	$ 404.4	$ 418.9