Equity Method Eligible Investments - Carrying Value and Ownership Percentages (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Kudu's Participation Contracts
Investments in unconsolidated affiliates
Carrying Value	$ 1,208.2	$ 1,008.4
Kudu's Participation Contracts | Minimum
Investments in unconsolidated affiliates
Ownership Interest	4.10%	4.10%
Kudu's Participation Contracts | Maximum
Investments in unconsolidated affiliates
Ownership Interest	30.00%	30.00%
Investment in MediaAlpha
Investments in unconsolidated affiliates
Ownership Interest	27.40%	26.60%
Carrying Value	$ 203.2	$ 201.6
PassportCard/DavidShield
Investments in unconsolidated affiliates
Ownership Interest	53.80%	53.80%
Carrying Value	$ 160.0	$ 150.0
BroadStreet SPV
Investments in unconsolidated affiliates
Ownership Interest	10.90%	0.00%
Carrying Value	$ 150.0	$ 0.0
Elementum
Investments in unconsolidated affiliates
Ownership Interest	26.60%	26.60%
Carrying Value	$ 35.0	$ 35.0
Other equity method eligible investments, at fair value
Investments in unconsolidated affiliates
Carrying Value	$ 256.3	$ 243.7