Reinsurance - Schedule of Reinsurance Activity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Direct Amount
Net premiums written and contract deposits, Direct Amount	$ 427.6	$ 424.0	$ 1,227.8	$ 1,186.5
Net premiums and contract charges earned, Direct Amount	296.0	276.7	877.1	812.3
Benefits, claims and settlement expenses, Direct Amount	196.6	205.2	596.5	615.6
Ceded to Other Companies
Net premiums written and contract deposits, Ceded to Other Companies	17.6	16.5	53.8	51.0
Net premiums and contract charges earned, Ceded to Other Companies	13.1	18.7	52.7	57.2
Benefits, claims and settlement expenses, Ceded to Other Companies	11.2	9.1	36.0	36.1
Assumed from Other Companies
Net premiums written and contract deposits, Assumed from Other Companies	6.3	8.4	21.4	28.2
Net premiums and contract charges earned, Assumed from Other Companies	6.2	8.0	20.8	27.5
Benefits, claims and settlement expenses, Assumed from Other Companies	5.9	3.1	14.4	8.1
Net Amount
Net premiums written and contract deposits, Net Amount	416.3	415.9	1,195.4	1,163.7
Net premiums and contract charges earned, Net Amount	289.1	266.0	845.2	782.6
Benefits, claims and settlement expenses, Net Amount	$ 191.3	$ 199.2	$ 574.9	$ 587.6