Income Taxes - Roll forward of interest accrued on unrecognized tax benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Balance as of January 1	$ 0.6	$ 0.5	$ 0.1
Interest expense related to unrecognized tax benefits	0.3	0.1	0.4
Balance as of December 31	0.9	0.6	0.5
Penalties in the consolidated income statements	0.0	0.0	$ 0.0
Accrued penalties on the consolidated balance sheets	0.0	$ 0.0
Unrecognized tax benefits, decrease resulting from statute of limitations	$ 1.8