Long-Duration Insurance Contracts - Amounts Recognized in the Statement of Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Liability for Future Policy Benefit, by Product Segment [Line Items]
Gross premiums or assessments	$ 240.9	$ 237.0
Interest expense	74.6	75.2
Whole Life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Gross premiums or assessments	28.9	28.1
Interest expense	12.6	12.2
Term Life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Gross premiums or assessments	47.4	45.9
Interest expense	5.9	5.3
Experience life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Gross premiums or assessments	29.2	30.6
Interest expense	42.0	43.0
Limited-Pay Whole Life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Gross premiums or assessments	7.1	7.2
Interest expense	3.1	2.8
Supplemental health
Liability for Future Policy Benefit, by Product Segment [Line Items]
Gross premiums or assessments	125.8	121.6
Interest expense	6.9	7.6
SPIA (life contingent)
Liability for Future Policy Benefit, by Product Segment [Line Items]
Gross premiums or assessments	2.5	3.6
Interest expense	$ 4.1	$ 4.3