Goodwill - Schedule of Changes in Carrying Amounts of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Mar. 31, 2024
Goodwill [Line Items]
Goodwill	$ 604.1	$ 603.9
Accumulated impairment losses	(59.5)	(59.5)
Total	544.6	544.4
Foreign currency translation	(0.2)
Commercial
Goodwill [Line Items]
Goodwill	388.1	388.0
Total	388.1	388.0
Foreign currency translation	(0.1)
Aviation
Goodwill [Line Items]
Goodwill	216.0	215.9
Accumulated impairment losses	(59.5)	(59.5)
Total	156.5	$ 156.4
Foreign currency translation	$ (0.1)