Reinsurance - Summary of Reinsurance Activity (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Direct Amount
Net premiums written and contract deposits, Direct Amount	$ 367.8	$ 360.8
Net premiums and contract charges earned, Direct Amount	264.0	260.4
Benefits, claims and settlement expenses, Direct Amount	192.9	181.6
Ceded to Other Companies
Net premiums written and contract deposits, Ceded to Other Companies	16.6	14.8
Net premiums and contract charges earned, Ceded to Other Companies	18.5	17.2
Benefits, claims and settlement expenses, Ceded to Other Companies	12.7	7.2
Assumed from Other Companies
Net premiums written and contract deposits, Assumed from Other Companies	10.4	12.4
Net premiums and contract charges earned, Assumed from Other Companies	10.4	12.6
Benefits, claims and settlement expenses, Assumed from Other Companies	3.0	0.8
Net Amount
Net premiums written and contract deposits, Net Amount	361.6	358.4
Net premiums and contract charges earned, Net Amount	255.9	255.8
Benefits, claims and settlement expenses, Net Amount	$ 183.2	$ 175.2