Income Taxes - Loss Before Tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
United States	$ (208.5)	$ (225.5)	$ (240.3)
Foreign	(21.3)	(69.3)	6.7
Loss before income taxes	$ (229.8)	$ (294.8)	$ (233.6)