Restructuring Charges 2020 Plan Restructuring Activity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Restructuring Cost and Reserve [Line Items]
Severance and termination costs	$ 0.0	$ 0.0	$ 0.4	$ 0.2
Lease impairment costs	(0.7)	(7.3)	(1.9)	(2.0)
Other restructuring costs	0.1	1.5	0.8	2.5
Restructuring charges	(0.6)	$ (5.8)	(0.7)	$ 0.7
Restructuring Reserve					$ 2.3
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	0.7		0.7		2.3
Lease impairment costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	0.0		0.0		0.0
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 0.0		0.0		$ 0.0
Non-cash Items [Member]
Restructuring Cost and Reserve [Line Items]
Severance and termination costs			0.0
Lease impairment costs			(0.5)
Restructuring charges			(0.5)
Cash Payments [Member]
Restructuring Cost and Reserve [Line Items]
Severance and termination costs			2.0
Lease impairment costs			0.0
Restructuring charges			$ 2.0