Investments (Summary Of Components Of Net Investment Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustment	$ 88,090	$ 73,081	$ 228,391	$ 238,720
Funds held interest income (expense)	970	746	4,262	4,182
Gross investment income	89,060	73,827	232,653	242,902
Investment expenses	(5,614)	(4,999)	(16,784)	(15,469)
Net investment income	83,446	68,828	215,869	227,433
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustment	52,515	52,098	157,515	159,363
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustment	7,966	8,390	26,083	27,235
Short-Term Investments And Cash [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustment	196	302	841	705
Limited Partnerships [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustment	19,254	6,569	18,862	32,109
Dividends From Parent's Shares [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustment	7,290	4,666	21,870	13,997
Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustment	$ 869	$ 1,056	$ 3,220	$ 5,311