Schedule II - Condensed Financial Information Of The Registrant (Condensed Statements Of Operations) (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
Net investment income	$ 126,253	$ 156,465	$ 158,618	$ 178,705	$ 184,865	$ 141,368	$ 165,731	$ 161,499	$ 620,041	$ 653,463	$ 547,793
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)
Other income (expense)									(23,089)	16,927	(22,476)
Net income (loss) of subsidiaries									56,549	71,493	(20,575)
Total revenues									4,693,961	4,705,807	4,498,578
Total claims and underwriting expenses	1,310,762	998,117	1,019,060	1,531,189	1,006,578	956,597	922,188	1,158,462	4,927,908	4,114,569	3,559,257
INCOME (LOSS) BEFORE TAXES									(233,947)	591,238	939,321
Income tax expense (benefit)									(153,461)	(19,516)	132,332
NET INCOME (LOSS)	41,042	63,054	131,312	(315,894)	302,533	174,200	156,673	(22,652)	(80,486)	610,754	806,989
Registrant [Member]
Net investment income									1,673	1,125	2,625
Net realized capital gains (losses)										7	(15,142)
Other income (expense)									(505)	(385)	(406)
Net income (loss) of subsidiaries									(71,233)	618,906	829,335
Total revenues									(70,065)	619,653	816,412
Other expenses									10,421	8,899	9,423
Total claims and underwriting expenses									10,421	8,899	9,423
INCOME (LOSS) BEFORE TAXES									(80,486)	610,754	806,988
NET INCOME (LOSS)									$ (80,486)	$ 610,754	$ 806,988