Income Taxes - Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current expense (benefit):
Federal	$ 1.7	$ (1.6)	$ (4.9)
State	0.1	(0.2)	0.3
Foreign	13.9	9.4	9.4
Total	15.7	7.6	4.8
Deferred (benefit) expense:
Federal	(7.1)	(8.0)	(5.9)
State	(1.2)	0.8	(0.6)
Foreign	1.1	(1.1)	0.7
Total	(7.2)	(8.3)	(5.8)
Income tax expense (benefit)	$ 8.5	$ (0.7)	$ (1.0)