Reinsurance (Summary of Reinsurance Activity) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Insurance [Abstract]
Net assumed written premiums	$ 12.1	$ 14.7	$ 45.9	$ 49.3
Net premiums earned	15.4	15.1	45.6	42.2
Provision for claims	10.0	10.7	29.3	28.8
Amortization of capitalized acquisition costs	$ 0.2	$ 0.4	$ 1.0	$ 1.0