Reinsurance - Summary of Reinsurance Activity (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Direct Amount
Net premiums written and contract deposits, Direct Amount	$ 394.7	$ 375.1	$ 762.5	$ 735.9
Net premiums and contract charges earned, Direct Amount	271.6	260.5	535.6	520.9
Benefits, claims and settlement expenses, Direct Amount	217.5	212.4	410.4	394.0
Ceded to Other Companies
Net premiums written and contract deposits, Ceded to Other Companies	17.9	16.5	34.5	31.3
Net premiums and contract charges earned, Ceded to Other Companies	20.0	18.7	38.5	35.9
Benefits, claims and settlement expenses, Ceded to Other Companies	14.3	18.5	27.0	25.7
Assumed from Other Companies
Net premiums written and contract deposits, Assumed from Other Companies	9.4	13.7	19.8	26.1
Net premiums and contract charges earned, Assumed from Other Companies	9.1	13.6	19.5	26.2
Benefits, claims and settlement expenses, Assumed from Other Companies	2.0	9.5	5.0	10.3
Net Amount
Net premiums written and contract deposits, Net Amount	386.2	372.3	747.8	730.7
Net premiums and contract charges earned, Net Amount	260.7	255.4	516.6	511.2
Benefits, claims and settlement expenses, Net Amount	$ 205.2	$ 203.4	$ 388.4	$ 378.6