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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair Value Measurements - Financial Instruments Based on Observable Inputs (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024	Oct. 20, 2020	Jul. 02, 2020
Senior Notes \| Senior Notes Due 2030
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Interest rate, stated percentage	4.875%	4.875%		4.875%
Junior Subordinated Debt \| Fixed Rate Reset Junior Subordinated notes due 2041
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Interest rate, stated percentage	6.625%	6.625%	6.625%
Fair Value \| Preference securities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Debt instrument, fair value disclosure	$ 57.6	$ 57.2
Fair Value \| Level 2 \| Senior Notes \| 4.875% Senior notes due 2030
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Debt instrument, fair value disclosure	318.6	319.7
Fair Value \| Level 2 \| Senior Subordinated Notes \| 6.625% Fixed Rate Reset Junior Subordinated notes due 2041
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Debt instrument, fair value disclosure	124.4	123.2
Carrying Value \| Preference securities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Debt instrument, fair value disclosure	58.4	58.4
Carrying Value \| Level 2 \| Senior Notes \| 4.875% Senior notes due 2030
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Debt instrument, fair value disclosure	325.8	325.6
Carrying Value \| Level 2 \| Senior Subordinated Notes \| 6.625% Fixed Rate Reset Junior Subordinated notes due 2041
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Debt instrument, fair value disclosure	$ 123.3	$ 123.3