Summary Of Significant Accounting Policies (Direct Premium Attributable By Segment) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Segment Reporting Information [Line Items]
Premiums written, net	$ 2,579,683	$ 2,558,825	$ 2,593,568
Private Passenger Automobile [Member]
Segment Reporting Information [Line Items]
Premiums written, net	2,105,602	2,115,763	2,158,038
Homeowners [Member]
Segment Reporting Information [Line Items]
Premiums written, net	285,188	261,560	240,885
Commercial Automobile [Member]
Segment Reporting Information [Line Items]
Premiums written, net	75,642	84,503	93,955
Other Lines [Member]
Segment Reporting Information [Line Items]
Premiums written, net	$ 113,251	$ 96,999	$ 100,690