Reinsurance - Summary of Reinsurance Activity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Direct Amount
Net premiums written and contract deposits, Direct Amount	$ 390.3	$ 366.0	$ 1,124.4	$ 1,037.8
Net premiums and contract charges earned, Direct Amount	262.0	230.9	783.4	696.6
Benefits, claims and settlement expenses, Direct Amount	177.3	164.5	577.4	444.7
Ceded to Other Companies
Net premiums written and contract deposits, Ceded to Other Companies	15.4	5.5	46.7	17.0
Net premiums and contract charges earned, Ceded to Other Companies	17.6	8.1	53.5	24.6
Benefits, claims and settlement expenses, Ceded to Other Companies	8.4	1.5	34.2	3.0
Assumed from Other Companies
Net premiums written and contract deposits, Assumed from Other Companies	13.4	2.6	39.5	6.6
Net premiums and contract charges earned, Assumed from Other Companies	13.4	2.6	39.6	6.8
Benefits, claims and settlement expenses, Assumed from Other Companies	4.7	1.8	15.0	4.5
Net Amount
Net premiums written and contract deposits, Net Amount	388.3	363.1	1,117.2	1,027.4
Net premiums and contract charges earned, Net Amount	257.8	225.4	769.5	678.8
Benefits, claims and settlement expenses, Net Amount	$ 173.6	$ 164.8	$ 558.2	$ 446.2