Investments - Schedule of Loans by Maturity (Details) $ in Millions	Sep. 30, 2024 USD ($) loan	Dec. 31, 2023 USD ($) loan
Cost
One Year or Less | $	$ 34.9	$ 19.7
Greater than One Year and Less than Three | $	128.1	34.9
Greater than Three Years and Less than Five Years | $	19.0	32.4
Greater than Five Years and Less than Seven Years | $	0.0	17.2
Greater than Seven Years and Less than Ten Years | $	52.9	40.6
Cost | $	$ 234.9	$ 144.8
Loan Count
One Year or Less | loan	3	4
Greater than One Year and Less than Three | loan	5	6
Greater than Three Years and Less than Five Years | loan	4	6
Greater than Five Years and Less than Seven Years | loan	0	4
Greater than Seven Years and Less than Ten Years | loan	5	8
Loan Count | loan	17	28