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Fair Value (Tables) | 9 Months Ended
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Sep. 30, 2024
Fair Value Disclosures [Abstract] |
Fair Values of Financial Instruments | The estimated fair values of the financial instruments were as follows:
|  | September 30, 2024 |  |  | December 31, 2023 |
|  | Carrying |  |  | Market |  |  | Carrying |  |  | Market |
(in millions) |  | Value |  |  | Value |  |  | Value |  |  | Value |
Financial Assets carried at: |  |  |  |  |  |  |  |  |  |  |  |
Fair Value through AOCI: |  |  |  |  |  |  |  |  |  |  |  |
Fixed maturities |  | $ | 8,620.0 |  |  | $ | 8,620.0 |  |  | $ | 7,985.3 |  |  | $ | 7,985.3 |
Fair Value through Net Income: |  |  |  |  |  |  |  |  |  |  |  |
Equity securities |  |  | 150.1 |  |  |  | 150.1 |  |  |  | 130.9 |  |  |  | 130.9 |
Other investments |  |  | 101.2 |  |  |  | 101.2 |  |  |  | 118.4 |  |  |  | 118.4 |
Amortized Cost/Cost: |  |  |  |  |  |  |  |  |  |  |  |
Other investments |  |  | 374.3 |  |  |  | 360.0 |  |  |  | 413.1 |  |  |  | 393.5 |
Cash and cash equivalents |  |  | 427.1 |  |  |  | 427.1 |  |  |  | 316.1 |  |  |  | 316.1 |
Total financial instruments |  | $ | 9,672.7 |  |  | $ | 9,658.4 |  |  | $ | 8,963.8 |  |  | $ | 8,944.2 |
Financial Liabilities carried at: |  |  |  |  |  |  |  |  |  |  |  |
Amortized Cost: |  |  |  |  |  |  |  |  |  |  |  |
Debt |  | $ | 783.9 |  |  | $ | 752.5 |  |  | $ | 783.2 |  |  | $ | 727.5 |
Fair Value, Investment Assets Measured on Recurring Basis | The following tables provide, for each hierarchy level, the Company’s investment assets that were measured at fair value on a recurring basis.
|  | September 30, 2024 |
(in millions) |  | Total |  |  | Level 1 |  |  | Level 2 |  |  | Level 3 |
Fixed maturities: |  |  |  |  |  |  |  |  |  |  |  |
U.S. Treasury and government agencies |  | $ | 576.8 |  |  | $ | 436.2 |  |  | $ | 140.6 |  |  | $ | — |
Foreign governments |  |  | 1.8 |  |  |  | — |  |  |  | 1.8 |  |  |  | — |
Municipals |  |  | 1,049.3 |  |  |  | — |  |  |  | 1,041.3 |  |  |  | 8.0 |
Corporates |  |  | 3,973.9 |  |  |  | — |  |  |  | 3,973.9 |  |  |  | — |
Residential mortgage-backed, U.S. agency backed |  |  | 1,478.4 |  |  |  | — |  |  |  | 1,478.4 |  |  |  | — |
Residential mortgage-backed, non-agency |  |  | 250.4 |  |  |  | — |  |  |  | 250.4 |  |  |  | — |
Commercial mortgage-backed |  |  | 586.2 |  |  |  | — |  |  |  | 580.0 |  |  |  | 6.2 |
Other asset-backed |  |  | 703.2 |  |  |  | — |  |  |  | 703.2 |  |  |  | — |
Total fixed maturities |  |  | 8,620.0 |  |  |  | 436.2 |  |  |  | 8,169.6 |  |  |  | 14.2 |
Equity securities |  |  | 150.1 |  |  |  | 142.3 |  |  |  | — |  |  |  | 7.8 |
Other investments |  |  | 3.8 |  |  |  | — |  |  |  | — |  |  |  | 3.8 |
Total investment assets at fair value |  | $ | 8,773.9 |  |  | $ | 578.5 |  |  | $ | 8,169.6 |  |  | $ | 25.8 |
|  | December 31, 2023 |
(in millions) |  | Total |  |  | Level 1 |  |  | Level 2 |  |  | Level 3 |
Fixed maturities: |  |  |  |  |  |  |  |  |  |  |  |
U.S. Treasury and government agencies |  | $ | 462.6 |  |  | $ | 324.3 |  |  | $ | 138.3 |  |  | $ | — |
Foreign governments |  |  | 2.2 |  |  |  | — |  |  |  | 2.2 |  |  |  | — |
Municipals |  |  | 1,185.2 |  |  |  | — |  |  |  | 1,176.6 |  |  |  | 8.6 |
Corporates |  |  | 3,849.7 |  |  |  | — |  |  |  | 3,849.6 |  |  |  | 0.1 |
Residential mortgage-backed, U.S. agency backed |  |  | 1,168.7 |  |  |  | — |  |  |  | 1,168.7 |  |  |  | — |
Residential mortgage-backed, non-agency |  |  | 142.2 |  |  |  | — |  |  |  | 142.2 |  |  |  | — |
Commercial mortgage-backed |  |  | 818.2 |  |  |  | — |  |  |  | 811.2 |  |  |  | 7.0 |
Other asset-backed |  |  | 356.5 |  |  |  | — |  |  |  | 356.5 |  |  |  | — |
Total fixed maturities |  |  | 7,985.3 |  |  |  | 324.3 |  |  |  | 7,645.3 |  |  |  | 15.7 |
Equity securities |  |  | 130.9 |  |  |  | 123.3 |  |  |  | — |  |  |  | 7.6 |
Other investments |  |  | 3.8 |  |  |  | — |  |  |  | — |  |  |  | 3.8 |
Total investment assets at fair value |  | $ | 8,120.0 |  |  | $ | 447.6 |  |  | $ | 7,645.3 |  |  | $ | 27.1 |
Estimated Fair Values of Financial Instruments Not Carried at Fair Value | The following tables provide, for each hierarchy level, the Company’s estimated fair values of financial instruments that were not carried at fair value:
|  | September 30, 2024 |
(in millions) |  | Total |  |  | Level 1 |  |  | Level 2 |  |  | Level 3 |
Assets: |  |  |  |  |  |  |  |  |  |  |  |
Cash and cash equivalents |  | $ | 427.1 |  |  | $ | 427.1 |  |  | $ | — |  |  | $ | — |
Other investments |  |  | 360.0 |  |  |  | — |  |  |  | 6.1 |  |  |  | 353.9 |
Total financial instruments |  | $ | 787.1 |  |  | $ | 427.1 |  |  | $ | 6.1 |  |  | $ | 353.9 |
Liabilities: |  |  |  |  |  |  |  |  |  |  |  |
Debt |  | $ | 752.5 |  |  | $ | — |  |  | $ | 752.5 |  |  | $ | — |
|  | December 31, 2023 |
(in millions) |  | Total |  |  | Level 1 |  |  | Level 2 |  |  | Level 3 |
Assets: |  |  |  |  |  |  |  |  |  |  |  |
Cash and cash equivalents |  | $ | 316.1 |  |  | $ | 316.1 |  |  | $ | — |  |  | $ | — |
Other investments |  |  | 393.5 |  |  |  | — |  |  |  | 6.1 |  |  |  | 387.4 |
Total financial instruments |  | $ | 709.6 |  |  | $ | 316.1 |  |  | $ | 6.1 |  |  | $ | 387.4 |
Liabilities: |  |  |  |  |  |  |  |  |  |  |  |
Debt |  | $ | 727.5 |  |  | $ | — |  |  | $ | 727.5 |  |  | $ | — |
Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) | The following tables provide a reconciliation for all assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3).
|  | Fixed Maturities |  |  |  |  |
(in millions) |  | Municipals |  | Corporates |  | Commercial mortgage- backed |  | Total |  | Equities and Other |  | Total Assets |
Three Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |
Balance July 1, 2024 |  | $ | 7.9 |  | $ | — |  | $ | 6.7 |  | $ | 14.6 |  | $ | 11.5 |  | $ | 26.1 |
Total gains (losses): |  |  |  |  |  |  |  |  |  |  |  |  |
Included in net realized and unrealized investment gains (losses) |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 0.1 |  |  | 0.1 |
Included in other comprehensive income (loss) - changes in net unrealized gains (losses) on investment securities |  |  | 0.3 |  |  | — |  |  | (0.4 | ) |  | (0.1 | ) |  | — |  |  | (0.1 | )
Settlements |  |  | (0.2 | ) |  | — |  |  | (0.1 | ) |  | (0.3 | ) |  | — |  |  | (0.3 | )
Balance September 30, 2024 |  | $ | 8.0 |  | $ | — |  | $ | 6.2 |  | $ | 14.2 |  | $ | 11.6 |  | $ | 25.8 |
Changes in net unrealized gains (losses) for the period included in other comprehensive income (loss) for assets held at the end of the period |  | $ | 0.3 |  | $ | — |  | $ | (0.4 | ) | $ | (0.1 | ) | $ | — |  | $ | (0.1 | )
Three Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |  |  |  |  |
Balance July 1, 2023 |  | $ | 8.8 |  | $ | 0.1 |  | $ | 7.2 |  | $ | 16.1 |  | $ | 11.2 |  | $ | 27.3 |
Total losses: |  |  |  |  |  |  |  |  |  |  |  |  |
Included in other comprehensive income (loss) - changes in net unrealized gains (losses) on investment securities |  |  | (0.2 | ) |  | — |  |  | (0.1 | ) |  | (0.3 | ) |  | — |  |  | (0.3 | )
Settlements |  |  | (0.1 | ) |  | — |  |  | (0.2 | ) |  | (0.3 | ) |  | — |  |  | (0.3 | )
Balance September 30, 2023 |  | $ | 8.5 |  | $ | 0.1 |  | $ | 6.9 |  | $ | 15.5 |  | $ | 11.2 |  | $ | 26.7 |
Changes in net unrealized gains (losses) for the period included in other comprehensive income (loss) for assets held at the end of the period |  | $ | (0.2 | ) | $ | — |  | $ | (0.1 | ) | $ | (0.3 | ) | $ | — |  | $ | (0.3 | )
| Fixed Maturities |  |  |  |  |
(in millions) | Municipals |  | Corporates |  | Commercial mortgage- backed |  | Total |  | Equities and Other |  | Total Assets |
Nine Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |  |  |  |
Balance January 1, 2024 | $ | 8.6 |  | $ | 0.1 |  | $ | 7.0 |  | $ | 15.7 |  | $ | 11.4 |  | $ | 27.1 |
Transfers out of Level 3 |  | — |  |  | (0.1 | ) |  | — |  |  | (0.1 | ) |  | — |  |  | (0.1 | )
Total gains (losses): |  |  |  |  |  |  |  |  |  |  |  |
Included in net realized and unrealized investment gains (losses) |  | — |  |  | — |  |  | — |  |  | — |  |  | 0.2 |  |  | 0.2 |
Included in other comprehensive income (loss) - changes in net unrealized gains (losses) on investment securities |  | 0.2 |  |  | — |  |  | (0.4 | ) |  | (0.2 | ) |  | — |  |  | (0.2 | )
Settlements |  | (0.8 | ) |  | — |  |  | (0.4 | ) |  | (1.2 | ) |  | — |  |  | (1.2 | )
Balance September 30, 2024 | $ | 8.0 |  | $ | — |  | $ | 6.2 |  | $ | 14.2 |  | $ | 11.6 |  | $ | 25.8 |
Changes in net unrealized gains (losses) for the period included in other comprehensive income (loss) for assets held at the end of the period | $ | 0.2 |  | $ | — |  | $ | (0.4 | ) | $ | (0.2 | ) | $ | — |  | $ | (0.2 | )
Nine Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |  |  |  |
Balance January 1, 2023 | $ | 9.3 |  | $ | 0.1 |  | $ | 7.5 |  | $ | 16.9 |  | $ | 11.1 |  | $ | 28.0 |
Total gains (losses): |  |  |  |  |  |  |  |  |  |  |  |
Included in net realized and unrealized investment gains (losses) |  | — |  |  | — |  |  | — |  |  | — |  |  | 0.1 |  |  | 0.1 |
Included in other comprehensive income (loss) - changes in net unrealized gains (losses) on investment securities |  | (0.1 | ) |  | — |  |  | (0.1 | ) |  | (0.2 | ) |  | — |  |  | (0.2 | )
Settlements |  | (0.7 | ) |  | — |  |  | (0.5 | ) |  | (1.2 | ) |  | — |  |  | (1.2 | )
Balance September 30, 2023 | $ | 8.5 |  | $ | 0.1 |  | $ | 6.9 |  | $ | 15.5 |  | $ | 11.2 |  | $ | 26.7 |
Changes in net unrealized gains (losses) for the period included in other comprehensive income (loss) for assets held at the end of the period | $ | (0.1 | ) | $ | — |  | $ | (0.1 | ) | $ | (0.2 | ) | $ | — |  | $ | (0.2 | )
Schedule of Additional Information About Significant Unobservable Inputs Used in Fair Valuations of Level 3 | The following table provides quantitative information about the significant unobservable inputs used by the Company in the fair value measurements of Level 3 assets.
|  |  |  |  |  |  | September 30, 2024 |  |  | December 31, 2023
|  | Valuation |  | Significant |  |  | Fair |  |  | Range |  |  | Fair |  |  | Range
(in millions) |  | Technique |  | Unobservable Inputs |  |  | Value |  |  | (Wtd Average) |  |  | Value |  |  | (Wtd Average)
Fixed maturities: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Municipals |  | Discounted cash flow |  | Discount for: Small issue size |  |  | $ | 8.0 |  |  | 6.1 - 6.8% (6.7%) |  |  | $ | 8.6 |  |  | 6.1 - 6.8% (6.7%)
Corporates |  | Discounted cash flow |  | Discount for: Small issue size Above-market coupon |  |  |  | — |  |  |  | — |  |  |  | 0.1 |  |  | 2.5% (2.5%) 0.3% (0.3%)
Commercial mortgage-backed |  | Discounted cash flow |  | Discount for: Small issue size Above-market coupon Lease structure |  |  | 6.2 |  |  | 3.0 - 5.0% (4.7%) 0.5% (0.5%) 0.3% (0.3%) |  |  |  | 7.0 |  |  | 3.0 - 3.1% (3.0%) 0.5% (0.5%) 0.3% (0.3%)
Equity securities |  | Market comparables |  | Net tangible asset |  |  | 1.4 |  |  | N/A |  |  |  | 1.2 |  |  | N/A
|  | Internal price based on financing round |  | Discount for: Market liquidity |  |  | 6.4 |  |  | 27.0% (27.0%) |  |  |  | 6.4 |  |  | 27.0% (27.0%)
Other |  | Discounted cash flow |  | Discount rate |  |  | 3.8 |  |  | 16.8% (16.8%) |  |  | 3.8 |  |  | 16.8% (16.8%)

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