Fair Value (Tables)

3 Months Ended

Mar. 31, 2023

Fair Value Disclosures [Abstract]

Fair Value of Financial Instruments

The estimated fair values of the financial instruments were as follows:

	March 31, 2023				December 31, 2022
	Carrying		Market		Carrying		Market
(in millions)	Value		Value		Value		Value
Financial Assets carried at:
Fair Value through AOCI:
Fixed maturities	$	7,678.2	$	7,678.2	$	7,481.8	$	7,481.8
Fair Value through Net Income:
Equity securities		234.8		234.8		241.9		241.9
Other investments		129.2		129.2		131.8		131.8
Amortized Cost/Cost:
Other investments		427.8		404.7		432.3		401.0
Cash and cash equivalents		181.5		181.5		305.0		305.0
Total financial instruments	$	8,651.5	$	8,628.4	$	8,592.8	$	8,561.5
Financial Liabilities carried at:
Amortized Cost:
Debt	$	782.6	$	724.5	$	782.4	$	713.9

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.

	March 31, 2023
(in millions)	Total		Level 1		Level 2		Level 3
Fixed maturities:
U.S. Treasury and government agencies	$	432.9	$	295.8	$	137.1	$	—
Foreign government		2.2		—		2.2		—
Municipal		1,125.8		—		1,116.7		9.1
Corporate		3,779.9		—		3,779.8		0.1
Residential mortgage-backed, U.S. agency backed		1,022.1		—		1,022.1		—
Residential mortgage-backed, non-agency		131.0		—		131.0		—
Commercial mortgage-backed		842.5		—		835.0		7.5
Other asset-backed		341.8		—		341.8		—
Total fixed maturities		7,678.2		295.8		7,365.7		16.7
Equity securities		234.8		227.3		—		7.5
Other investments		3.6		—		—		3.6
Total investment assets at fair value	$	7,916.6	$	523.1	$	7,365.7	$	27.8

	December 31, 2022
(in millions)	Total		Level 1		Level 2		Level 3
Fixed maturities:
U.S. Treasury and government agencies	$	420.2	$	282.7	$	137.5	$	—
Foreign government		2.2		—		2.2		—
Municipal		1,076.1		—		1,066.8		9.3
Corporate		3,729.9		—		3,729.8		0.1
Residential mortgage-backed, U.S. agency backed		974.0		—		974.0		—
Residential mortgage-backed, non-agency		99.8		—		99.8		—
Commercial mortgage-backed		836.4		—		828.9		7.5
Other asset-backed		343.2		—		343.2		—
Total fixed maturities		7,481.8		282.7		7,182.2		16.9
Equity securities		241.9		234.4		—		7.5
Other investments		3.6		—		—		3.6
Total investment assets at fair value	$	7,727.3	$	517.1	$	7,182.2	$	28.0

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:

	March 31, 2023
(in millions)	Total		Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents	$	181.5	$	181.5	$	—	$	—
Other investments		404.7		—		6.0		398.7
Total financial instruments	$	586.2	$	181.5	$	6.0	$	398.7
Liabilities:
Debt	$	724.5	$	—	$	724.5	$	—

	December 31, 2022
(in millions)	Total		Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents	$	305.0	$	305.0	$	—	$	—
Other investments		401.0		—		6.0		395.0
Total financial instruments	$	706.0	$	305.0	$	6.0	$	395.0
Liabilities:
Debt	$	713.9	$	—	$	713.9	$	—

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)	Municipal			Corporate		Commercial mortgage- backed			Total			Equity and Other			Total Assets
Three Months Ended March 31, 2023
Balance January 1, 2023	$	9.3		$	0.1	$	7.5		$	16.9		$	11.1		$	28.0
Total gains included in other comprehensive   income-net appreciation on   available-for-sale securities		0.1			—		0.2			0.3			—			0.3
Settlements		(0.3	)		—		(0.2	)		(0.5	)		—			(0.5	)
Balance March 31, 2023	$	9.1		$	0.1	$	7.5		$	16.7		$	11.1		$	27.8
Change in unrealized gains for the period included in other comprehensive income for assets held at the end of the period	$	0.1		$	—	$	0.2		$	0.3		$	—		$	0.3
Three Months Ended March 31, 2022
Balance January 1, 2022	$	14.0		$	0.1	$	11.3		$	25.4		$	14.4		$	39.8
Total losses:
Included in total net realized and unrealized investment losses		—			—		—			—			(5.3	)		(5.3	)
Included in other comprehensive loss-net depreciation on available-for-sale securities		(0.6	)		—		(0.5	)		(1.1	)		—			(1.1	)
Settlements		(1.1	)		—		(0.2	)		(1.3	)		—			(1.3	)
Balance March 31, 2022	$	12.3		$	0.1	$	10.6		$	23.0		$	9.1		$	32.1
Change in unrealized losses for the period included in other comprehensive loss for assets held at the end of the period	$	(0.6	)	$	—	$	(0.5	)	$	(1.1	)	$	—		$	(1.1	)

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. Where discounted cash flows were used in the valuation of fixed maturities, the internally-developed discount rate was adjusted by the significant unobservable inputs shown in the table.

			March 31, 2023			December 31, 2022
	Valuation	Significant	Fair		Range	Fair		Range
(in millions)	Technique	Unobservable Inputs	Value		(Wtd Average)	Value		(Wtd Average)
Fixed maturities:
Municipal	Discounted cash flow	Discount for:    Small issue size	$	9.1	4.5 - 6.8% (6.6%)	$	9.3	4.5 - 6.8% (6.6%)
Corporate	Discounted cash flow	Discount for:    Small issue size    Above-market coupon	0.1		2.5% (2.5%) 0.3% (0.3%)		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	7.5		3.0 - 3.1% (3.0%) 0.5% (0.5%) 0.3% (0.3%)		7.5	3.0 - 3.1% (3.0%) 0.5% (0.5%) 0.3% (0.3%)
Equity securities	Market comparables	Net tangible asset	1.1		N/A		1.1	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	3.6		17.2% (17.2%)	3.6		17.2% (17.2%)