Retrocession Arrangements and Reinsurance Ceded Receivables (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Ceded Credit Risk [Line Items]
Reinsurance Claims Recoverables	$ 260.1	$ 143.0
Claims Recoverable From Retrocessionaires Past Due	$ 19.6	$ 10.9
AM Best, A- Rating [Member]
Ceded Credit Risk [Line Items]
Ceded Credit Risk, Disclosure	“A- (excellent)”	“A- (excellent)”