Reinsurance (Summary of Reinsurance Activity) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Insurance [Abstract]
Net assumed written premiums	$ 14.7	$ 11.4	$ 49.3	$ 39.1
Net premiums earned	15.1	12.9	42.2	38.2
Provision for claims	10.7	8.2	28.8	23.1
Amortization of capitalized acquisition costs	$ 0.4	$ 0.2	$ 1.0	$ 0.9