Reinsurance (Premiums Written And Earned And Incurred Losses And LAE)(Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reinsurance [Abstract]
Written premiums: Direct	$ 1,240,761	$ 1,050,248	$ 808,526
Written premiums: Assumed	3,196,707	2,519,142	2,749,993
Written premiums: Ceded	(2,320,091)	(1,877,789)	(1,804,508)
Net written premiums	2,117,377	1,691,601	1,754,011
Premiums earned: Direct	1,183,542	1,032,576	867,340
Premiums earned: Assumed	3,024,825	2,687,521	2,734,765
Premium earned: Ceded	(2,202,006)	(1,946,199)	(1,808,250)
Net premiums earned	2,006,361	1,773,898	1,793,855
Incurred losses and LAE: Direct	1,153,004	910,136	738,823
Incurred losses and LAE: Assumed	1,473,297	1,630,386	2,491,002
Incurred losses and LAE: Ceded	(1,354,145)	(1,290,778)	(1,352,222)
Net incurred losses and LAE	$ 1,272,156	$ 1,249,744	$ 1,877,603