INVESTMENTS - Schedule of Credit Ratings (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2025	Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 320.4	$ 309.1
Fair Value	$ 322.7	$ 306.8
AFS securities \| Credit rating
Debt Securities, Available-for-sale [Line Items]
Concentration percentage (in percent)	100.00%	100.00%
AAA
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 67.5	$ 75.2
Fair Value	$ 67.8	$ 74.8
AAA \| AFS securities \| Credit rating
Debt Securities, Available-for-sale [Line Items]
Concentration percentage (in percent)	21.00%	24.40%
AA+, AA, AA-, A-1+
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 151.5	$ 146.0
Fair Value	$ 152.7	$ 145.0
AA+, AA, AA-, A-1+ \| AFS securities \| Credit rating
Debt Securities, Available-for-sale [Line Items]
Concentration percentage (in percent)	47.30%	47.30%
A+, A, A-
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 82.0	$ 67.8
Fair Value	$ 82.6	$ 67.1
A+, A, A- \| AFS securities \| Credit rating
Debt Securities, Available-for-sale [Line Items]
Concentration percentage (in percent)	25.60%	21.90%
BB+
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 0.1
Fair Value	$ 0.1
BB+ \| AFS securities \| Credit rating
Debt Securities, Available-for-sale [Line Items]
Concentration percentage (in percent)	0.00%
BBB+, BBB, BBB-
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 19.3	$ 20.1
Fair Value	$ 19.5	$ 19.9
BBB+, BBB, BBB- \| AFS securities \| Credit rating
Debt Securities, Available-for-sale [Line Items]
Concentration percentage (in percent)	6.10%	6.40%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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