Restricted Securities Available For Sale (Tables)

9 Months Ended

Sep. 30, 2024

Investments, Debt and Equity Securities [Abstract]

Schedule of Restricted Securities Available for Sale

Restricted securities available for sale consist of the following:

(In millions)	As of September 30, 2024
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Corporate bonds	$	50.3	$	0.9	$	(0.3)	$	50.9
U.S. Government and agency securities	39.5		0.6		(0.3)		39.8
Asset-backed securities	21.2		0.2		—		21.4
Mortgage-backed securities	1.8		—		—		1.8
Total restricted securities available for sale	$	112.8	$	1.7	$	(0.6)	$	113.9
(In millions)	As of December 31, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Corporate bonds	$	40.5	$	0.3	$	(0.9)	$	39.9
U.S. Government and agency securities	35.2		0.2		(0.9)		34.5
Asset-backed securities	18.0		0.1		(0.2)		17.9
Municipal securities	0.7		—		—		0.7
Mortgage-backed securities	0.2		—		—		0.2
Total restricted securities available for sale	$	94.6	$	0.6	$	(2.0)	$	93.2

Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value

The fair value and gross unrealized losses for restricted securities available for sale, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, are as follows:

(In millions)	Securities Available for Sale with Gross Unrealized Losses as of September 30, 2024
	Less than 12 Months				12 Months or More
	Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Total Estimated Fair Value		Total Gross Unrealized Losses
Corporate bonds	$	2.9	$	—	$	9.6	$	(0.3)	$	12.5	$	(0.3)
U.S. Government and agency securities	0.5		—		10.4		(0.3)		10.9		(0.3)
Asset-backed securities	—		—		3.6		—		3.6		—
Mortgage-backed securities	—		—		0.1		—		0.1		—
Total restricted securities available for sale	$	3.4	$	—	$	23.7	$	(0.6)	$	27.1	$	(0.6)

(In millions)	Securities Available for Sale with Gross Unrealized Losses as of December 31, 2023
	Less than 12 Months				12 Months or More
	Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Total Estimated Fair Value		Total Gross Unrealized Losses
Corporate bonds	$	2.7	$	—	$	18.4	$	(0.9)	$	21.1	$	(0.9)
U.S. Government and agency securities	6.8		(0.1)		16.4		(0.8)		23.2		(0.9)
Asset-backed securities	1.6		—		7.3		(0.2)		8.9		(0.2)
Mortgage-backed securities	—		—		0.2		—		0.2		—
Total restricted securities available for sale	$	11.1	$	(0.1)	$	42.3	$	(1.9)	$	53.4	$	(2.0)

Schedule of Cost and Estimated Fair Values of Debt Securities by Contractual Maturity

The cost and estimated fair values of debt securities by contractual maturity were as follows (securities with multiple maturity dates are classified in the period of final maturity). Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

(In millions)	As of
	September 30, 2024				December 31, 2023
Contractual Maturity	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
Within one year	$	8.8	$	8.7	$	6.9	$	6.8
Over one year to five years	93.6		94.6		80.5		79.1
Over five years to ten years	10.3		10.6		7.1		7.2
Over ten years	0.1		—		0.1		0.1
Total restricted securities available for sale	$	112.8	$	113.9	$	94.6	$	93.2