Consolidated Statements Of Operations And Comprehensive Income (Loss) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
REVENUES:
Premiums earned	$ 4,101,347	$ 3,934,625	$ 3,894,098
Net investment income	620,041	653,463	547,793
Net realized capital gains (losses):
Other-than-temporary impairments on fixed maturity securities	(16,223)	(2,975)	(13,210)
Other-than-temporary impairments on fixed maturity securities transferred to other comprehensive income (loss)
Other net realized capital gains (losses)	23,146	104,886	10,898
Total net realized capital gains (losses)	6,923	101,911	(2,312)
Realized gain on debt repurchase			78,271
Net derivative gain (loss)	(11,261)	(1,119)	3,204
Other income (expense)	(23,089)	16,927	(22,476)
Total revenues	4,693,961	4,705,807	4,498,578
CLAIMS AND EXPENSES:
Incurred losses and loss adjustment expenses	3,726,204	2,945,712	2,374,058
Commission, brokerage, taxes and fees	950,521	931,855	928,333
Other underwriting expenses	182,403	166,258	167,178
Corporate expenses	16,461	14,914	17,607
Interest, fees and bond issue cost amortization expense	52,319	55,830	72,081
Total claims and expenses	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)	(80,486)	610,754	806,989
Other comprehensive income (loss), net of tax	34,720	60,220	621,201
COMPREHENSIVE INCOME (LOSS)	$ (45,766)	$ 670,974	$ 1,428,190
EARNINGS PER COMMON SHARE:
Basic	$ (1.49)	$ 10.73	$ 13.26
Diluted	$ (1.49)	$ 10.70	$ 13.22
Dividends declared	$ 1.92	$ 1.92	$ 1.92