Investments (Schedule Of Net Investment Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net investment income	$ 37,635	$ 42,451	$ 71,023	$ 89,660
Fixed maturity investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net investment income	32,662	37,219	65,187	84,105
Equity securities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net investment income	4,409	4,963	7,608	8,495
Other invested assets [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net investment income	3,843	3,681	5,307	4,223
Cash and cash equivalents [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net investment income	529	550	1,017	1,157
Expenses [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net investment income	$ (3,808)	$ (3,962)	$ (8,096)	$ (8,320)