Investments (Components Of Net Realized Capital Gains (Losses)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporary impairments									$ (16,223)	$ (2,975)	$ (13,210)
Short-term investments gain (loss)									2	8	40
Total net realized capital gains (losses)	137,283	(137,671)	(4,845)	12,156	32,591	38,295	(41,693)	72,718	6,923	101,911	(2,312)
Fair Value [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales									8,021	6,136	7,510
Gains (losses) from fair value adjustments									11,130	55,308	30,908
Fair Value [Member] | Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales									(905)	775	682
Gains (losses) from fair value adjustments									(15,518)	15,091	9,337
Market Value [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales									38	77	8,087
Market Value [Member] | Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporary impairments									(16,223)	(2,975)	(13,210)
Gains (losses) from sales									$ 20,378	$ 27,491	$ (45,666)