Reinsurance - Summary of Reinsurance Activity (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Direct Amount
Net premiums written and contract deposits, Direct Amount	$ 374.5	$ 351.2	$ 734.1	$ 671.8
Net premiums and contract charges earned, Direct Amount	260.9	231.5	521.4	465.7
Benefits, claims and settlement expenses, Direct Amount	220.6	144.6	400.1	280.2
Ceded to Other Companies
Net premiums written and contract deposits, Ceded to Other Companies	16.4	5.6	31.3	11.5
Net premiums and contract charges earned, Ceded to Other Companies	18.7	8.1	35.9	16.5
Benefits, claims and settlement expenses, Ceded to Other Companies	14.3	(1.0)	25.8	1.5
Assumed from Other Companies
Net premiums written and contract deposits, Assumed from Other Companies	13.7	2.5	26.1	4.0
Net premiums and contract charges earned, Assumed from Other Companies	13.6	2.4	26.2	4.2
Benefits, claims and settlement expenses, Assumed from Other Companies	1.3	1.5	10.3	2.7
Net Amount
Net premiums written and contract deposits, Net Amount	371.8	348.1	728.9	664.3
Net premiums and contract charges earned, Net Amount	255.8	225.8	511.7	453.4
Benefits, claims and settlement expenses, Net Amount	$ 207.6	$ 147.1	$ 384.6	$ 281.4