Schedule IV - Reinsurance (Details) (Total Property And Liability Insurance Premiums Earned [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Total Property And Liability Insurance Premiums Earned [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount	$ 1,183,542	$ 1,032,576	$ 867,340
Ceded to Other Companies	2,202,006	1,946,199	1,808,250
Assumes from Other Companies	3,024,825	2,687,521	2,734,765
Net Amount	$ 2,006,361	$ 1,773,898	$ 1,793,855
Assumed to Net	150.80%	151.50%	152.50%