Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
REVENUES:
Net premiums written	$ 4,357,368		$ 3,850,926		$ 3,730,095
Change in net unearned premiums	(196,501)		(15,344)		75,754
Net premiums earned	4,160,867		3,835,582		3,805,849
Net investment income	526,351		530,525		379,008
Insurance service fees	92,843		85,405		93,245
Net investment gains (losses):
Net realized gains on investment sales	125,881		65,786		104,453
Other-than-temporary impairments	(400)	[1]	(9,205)	[1]	(151,727)	[1]
Portion of impairments reclassified to other comprehensive income	0		0		8,866
Net investment gains (losses)	125,481		56,581		(38,408)
Revenues from wholly-owned investees	248,678		214,454		189,347
Other income	1,764		1,522		2,137
Total revenues	5,155,984		4,724,069		4,431,178
OPERATING COSTS AND EXPENSES:
Losses and loss expenses	2,658,365		2,309,867		2,336,707
Other operating costs and expenses	1,621,329		1,496,362		1,440,838
Expenses from wholly-owned investees	245,495		207,566		183,414
Interest expense	112,512		106,969		87,989
Total operating costs and expenses	4,637,701		4,120,764		4,048,948
Income before income taxes	518,283		603,305		382,230
Income tax expense	(123,550)		(153,739)		(73,150)
Net income before noncontrolling interests	394,733		449,566		309,080
Noncontrolling interests	70		(279)		(23)
Net income to common stockholders	$ 394,803		$ 449,287		$ 309,057
NET INCOME PER SHARE:
Basic	$ 2.83		$ 3.02		$ 1.93
Diluted	$ 2.71		$ 2.90		$ 1.86

[1] Includes change in valuation allowance for loans receivable of $0, $6,082,000 and $12,418,000 for the years ended December 31, 2011, 2010 and 2009, respectively.