Income Taxes - Unrecognized Income Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Unrecognized Tax Benefits
Unrecognized tax benefits at beginning of the year	$ 0.7	$ 1.7	$ 1.9
Additions for tax positions acquired during the current period	34.4	0.0	0.0
Additions (reductions) for tax positions taken during the prior period	3.7	0.0	0.4
Reductions relating to settlements with taxing authorities	(1.6)	(0.3)	0.0
Lapse of statutes of limitation	(0.2)	(0.7)	(0.6)
Unrecognized tax benefits at end of the year	$ 37.0	$ 0.7	$ 1.7