Employee Retirement Plans - Components of net retirement cost (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Contribution Plan, Cost		$ 2.6	$ 2.2	$ 5.0	$ 4.3
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	[1]	$ 0.1	$ 0.1	$ 0.3	$ 0.3

[1] The non-service cost components of net periodic benefit cost are included in other, net (income) expense in our Consolidated Statements of Operations.