Property And Liability Insurance Earned Premiums (Schedule Of Property And Liability Insurance Earned Premiums) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Property And Liability Insurance Earned Premiums [Abstract]
Direct amounts	$ 2,569,661	$ 2,569,942	$ 2,628,507
Ceded to other companies	(4,134)	(4,468)	(4,214)
Assumed	530	1,211	840
Net amounts	$ 2,566,057	$ 2,566,685	$ 2,625,133