Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Intangible Assets
Trade names, gross carrying value	$ 23.3	$ 23.3
Customer relationships
Intangible Assets
Intangible assets at cost	21.7	21.7
Amortization expense	$ 0.3	1.4	$ 1.7
Accumulated amortization		$ 21.2	$ 20.9
Weighted average remaining useful life (in years)	1 year 3 months 18 days