Retrocession Arrangements and Reinsurance Ceded Receivables (Narrative) (USD $) In Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2010
Retrocession Arrangements And Reinsurance Ceded Receivables Abstract
Retrocession Pool Participants Minimum AM Best Rating	A- (excellent)	A- (excellent)
Reinsurance Claims Recoverables	$ 165.9	$ 162.4
Claims Recoverable From Retrocessionaires Past Due	$ 12.4	$ 16.0