Investments (Summary Of Net Realized Investment Gains And The Change In Net Unrealized Gains On Investments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Schedule of Available-for-sale Securities [Line Items]
Realized gains	$ 12,979	$ 22,876	$ 34,383	$ 40,915
Realized losses	(7,748)	(10,037)	(9,027)	(15,492)
Other-than-temporary impairment losses recognized in net income	(3,159)	(9,984)	(4,151)	(14,859)
Net realized investment gains	5,231	12,839	25,356	25,423
Change in net unrealized gains on investments	136,470	(148,327)	330,305	(30,965)
Sales Of Fixed Maturities [Member]
Schedule of Available-for-sale Securities [Line Items]
Realized gains	2,576	1,858	7,863	12,560
Realized losses	(118)	(53)	(457)	(633)
Sales Of Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Realized gains	10,403	20,078	25,865	25,896
Realized losses	(383)	0	(331)	0
Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Realized gains	0	940	655	2,459
Realized losses	(4,088)	0	(4,088)	0
Fixed Maturities [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in net unrealized gains on investments	37,488	113,936	82,078	178,359
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in net unrealized gains on investments	98,964	(262,264)	248,214	(209,346)
Short-Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in net unrealized gains on investments	$ 18	$ 1	$ 13	$ 22