Reinsurance (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Ceded Credit Risk [Line Items]
Reinsurance Claims Recoverables	$ 267.4	$ 233.7
Claims Recoverable From Retrocessionaires Past Due	$ 3.5	$ 2.0
AM Best, A- Rating [Member]
Ceded Credit Risk [Line Items]
Ceded Credit Risk, Disclosure	“A- (excellent)”	“A- (excellent)”