Schedule II - Condensed Financial Information of Registrant (Statements of Income (Parent Company)) (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
Consolidated Financial Information of Registrant
Net investment gains (losses)									$ 125,481	$ 56,581	$ (38,408)
Other income									1,764	1,522	2,137
Total revenues	1,370,953	1,279,731	1,270,949	1,234,351	1,231,342	1,176,112	1,163,068	1,153,547	5,155,984	4,724,069	4,431,178
Operating costs and expense									4,637,701	4,120,764	4,048,948
Interest expense									112,512	106,969	87,989
Income before income taxes									518,283	603,305	382,230
Federal income taxes:
Income tax expense									(123,550)	(153,739)	(73,150)
Net income	117,926	77,308	83,082	116,487	126,851	93,619	110,207	118,610	394,803	449,287	309,057
Parent Company [Member]
Consolidated Financial Information of Registrant
Management fees and investment income including dividends from subsidiaries of $502,327, $405,917 and $150,545 for the years ended December 31, 2011, 2010 and 2009, respectively									514,057	411,623	159,361
Net investment gains (losses)									45,962	(1,891)	20,961
Other income									96	158	206
Total revenues									560,115	409,890	180,528
Operating costs and expense									118,922	117,658	88,276
Interest expense									111,184	105,510	87,054
Income before income taxes									330,009	186,722	5,198
Federal income taxes:
Federal income taxes provided by subsidiaries on a separate return basis									79,200	28,377	117,133
Federal income tax expense on a consolidated return basis									(89,144)	(138,389)	(58,644)
Income tax expense									(9,944)	(110,012)	58,489
Income before undistributed equity in net income (loss) of subsidiaries									320,065	76,710	63,687
Equity in undistributed net income (loss) of subsidiaries									74,738	372,577	245,370
Net income									$ 394,803	$ 449,287	$ 309,057