DEFERRED ACQUISITION COSTS, PRESENT VALUE OF FUTURE PROFITS AND SALES INDUCEMENTS - PRESENT VALUE OF FUTURE PROFITS (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025
Movement in Present Value of Future Insurance Profits [Roll Forward]
Beginning of period	$ 143.6	$ 161.0
Amortization expense	(8.1)	(8.9)
End of period	135.5	152.1
Supplemental health
Movement in Present Value of Future Insurance Profits [Roll Forward]
Beginning of period	117.4	128.8
Amortization expense	(5.5)	(5.8)
End of period	111.9	123.0
Medicare supplement
Movement in Present Value of Future Insurance Profits [Roll Forward]
Beginning of period	12.0	15.7
Amortization expense	(1.6)	(1.9)
End of period	10.4	13.8
Long-term care
Movement in Present Value of Future Insurance Profits [Roll Forward]
Beginning of period	3.7	4.4
Amortization expense	(0.3)	(0.4)
End of period	3.4	4.0
Traditional life
Movement in Present Value of Future Insurance Profits [Roll Forward]
Beginning of period	9.9	11.3
Amortization expense	(0.7)	(0.7)
End of period	9.2	10.6
Fixed indexed annuities
Movement in Present Value of Future Insurance Profits [Roll Forward]
Beginning of period	0.4	0.5
Amortization expense	0.0	(0.1)
End of period	0.4	0.4
Fixed interest annuities
Movement in Present Value of Future Insurance Profits [Roll Forward]
Beginning of period	0.2	0.3
Amortization expense	0.0	0.0
End of period	$ 0.2	$ 0.3