Recent Accounting Pronouncements Recent Accounting Pronouncements (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2010	Dec. 31, 2011
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets					$ 51,000,000
Deferred policy acquisition costs	400,727,000		400,727,000			364,937,000
Stockholders equity	4,324,401,000		4,324,401,000			3,953,356,000
Other operating expenses	451,487,000	407,149,000	1,332,024,000	1,196,936,000
Income before income taxes	133,693,000	96,146,000	469,435,000	364,368,000
Federal and foreign income taxes	(32,685,000)	(19,775,000)	(124,291,000)	(90,282,000)
Net Income (Loss)	100,947,000	76,410,000	345,103,000	274,184,000
Earnings Per Share, Basic	$ 0.74	$ 0.55	$ 2.51	$ 1.95
Earnings Per Share, Diluted	$ 0.71	$ 0.53	$ 2.41	$ 1.87
Scenario, Previously Reported [Member]
Deferred policy acquisition costs						448,795,000
Deferred tax liabilities						31,623,000
Stockholders equity						4,008,426,000
Other operating expenses	405,850,000			1,193,040,000
Income before income taxes	97,445,000			368,264,000
Federal and foreign income taxes	(20,176,000)			(91,485,000)
Net Income (Loss)	77,308,000			276,877,000
Earnings Per Share, Basic	$ 0.56			$ 1.97
Earnings Per Share, Diluted	$ 0.53			$ 1.89
Restatement Adjustment [Member]
Deferred policy acquisition costs						364,937,000
Deferred tax liabilities						2,835,000
Stockholders equity						3,953,356,000
Other operating expenses	407,149,000			1,196,936,000
Income before income taxes	96,146,000			364,368,000
Federal and foreign income taxes	(19,775,000)			(90,282,000)
Net Income (Loss)	$ 76,410,000			$ 274,184,000
Earnings Per Share, Basic	$ 0.55			$ 1.95
Earnings Per Share, Diluted	$ 0.53			$ 1.87