Unaudited Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenues
Gross premiums written	$ 1,056,076	$ 1,095,326	$ 3,786,802	$ 3,735,091
Net premiums written	1,043,240	1,079,557	3,652,571	3,606,444
Decrease (increase) in unearned premiums	193,851	214,762	(334,772)	(140,091)
Net premiums earned	1,237,091	1,294,319	3,317,799	3,466,353
Net investment income	135,266	163,647	435,669	473,608
Net realized and unrealized investment gains (losses)	257,429	26,139	488,296	(7,860)
Other income	2,744	1,434	8,143	4,843
Total revenues	1,632,530	1,485,539	4,249,907	3,936,944
Expenses
Losses and loss expenses and life policy benefits	721,137	881,626	2,003,759	3,303,366
Acquisition costs	247,058	262,489	691,388	699,589
Other operating expenses	94,697	103,822	299,055	321,813
Interest expense	12,224	12,216	36,668	36,730
Amortization of intangible assets	8,893	9,520	26,679	27,512
Net foreign exchange losses (gains)	2,015	(10,587)	(3,165)	(20,020)
Total expenses	1,086,024	1,259,086	3,054,384	4,368,990
Income (loss) before taxes and interest in earnings (losses) of equity investments	546,506	226,453	1,195,523	(432,046)
Income tax expense	64,149	41,803	181,458	65,632
Interest in earnings (losses) of equity investments	4,349	(4,527)	8,929	(4,970)
Net income (loss)	486,706	180,123	1,022,994	(502,648)
Preferred dividends	15,405	14,352	46,216	31,614
Net income (loss) available to common shareholders	471,301	165,771	976,778	(534,262)
Comprehensive income (loss)
Net income (loss)	486,706	180,123	1,022,994	(502,648)
Change in currency translation adjustment	32,992	(54,958)	31,042	(10,874)
Change in other accumulated comprehensive (loss) income, net of tax	(827)	1,106	(883)	(1,049)
Comprehensive income (loss)	$ 518,871	$ 126,271	$ 1,053,153	$ (514,571)
Per share data
Basic net income (loss)	$ 7.62	$ 2.45	$ 15.34	$ (7.88)
Diluted net income (loss)	$ 7.53	$ 2.43	$ 15.19	$ (7.88)
Weighted average number of common shares outstanding	61,837,328	67,743,296	63,679,114	67,788,427
Weighted average number of common shares and common share equivalents outstanding	62,606,761	68,181,982	64,284,125	67,788,427
Dividends declared per common share	$ 0.62	$ 0.60	$ 1.86	$ 1.75