Reinsurance - Summary of Reinsurance Activity (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Direct Amount
Net premiums written and contract deposits, Direct Amount	$ 359.6	$ 320.6
Net premiums and contract charges earned, Direct Amount	260.5	234.2
Benefits, claims and settlement expenses, Direct Amount	179.5	135.6
Ceded to Other Companies
Net premiums written and contract deposits, Ceded to Other Companies	14.9	5.9
Net premiums and contract charges earned, Ceded to Other Companies	17.2	8.4
Benefits, claims and settlement expenses, Ceded to Other Companies	11.5	2.5
Assumed from Other Companies
Net premiums written and contract deposits, Assumed from Other Companies	12.4	1.5
Net premiums and contract charges earned, Assumed from Other Companies	12.6	1.8
Benefits, claims and settlement expenses, Assumed from Other Companies	9.0	1.2
Net Amount
Net premiums written and contract deposits, Net Amount	357.1	316.2
Net premiums and contract charges earned, Net Amount	255.9	227.6
Benefits, claims and settlement expenses, Net Amount	$ 177.0	$ 134.3