Reinsurance (Summary of Reinsurance Activity) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Insurance [Abstract]
Net assumed written premiums	$ 11.9	$ 14.2	$ 27.7	$ 30.4
Net premiums earned	13.1	11.7	25.3	22.0
Provision for claims	8.3	7.3	14.9	12.5
Amortization of capitalized acquisition costs	$ 0.4	$ 0.2	$ 0.7	$ 0.5