Reinsurance (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Historical Average Claims Ratios, Period, Minimum		5 years
Historical Average Claims Ratios, Period, Maximum		10 years
Hollenfels [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Share of incurred and paid claims	$ 1.5	$ 2.6
Share of claims incurred but not reported	$ 1.7	$ 3.8