Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net income	$ 529,324	$ 497,161	$ 498,866
Adjustments to reconcile net income to cash provided from operations:
Increase in future policy benefits	497,306	431,362	544,086
Increase (decrease) in other policy benefits	(8,115)	(2,776)	1,110
Deferral of policy acquisition costs	(480,818)	(441,825)	(442,294)
Amortization of deferred policy acquisition costs	385,167	364,583	376,988
Change in current and deferred income taxes	122,538	30,899	68,326
Realized (gains) losses on sale of investments and properties	(37,833)	(25,904)	(40,190)
Change in other receivables	(89,677)	(22,565)	(24,716)
Loss on disposal of subsidiary	0	455	35,013
Other, net	24,947	28,074	11,404
Cash provided from operations	942,839	859,464	1,028,593
Investments sold or matured:
Fixed maturities available for sale-sold	345,601	224,335	325,950
Fixed maturities available for sale-matured, called, and repaid	736,900	410,356	638,860
Equity securities	0	28,700	0
Other long-term investments	9,458	18,937	5,767
Total investments sold or matured	1,091,959	682,328	970,577
Acquisition of investments:
Fixed maturities-available for sale	(1,431,690)	(1,104,231)	(1,908,109)
Equity securities	0	(28,772)	0
Other long-term investments	(1,786)	(6,246)	(905)
Total investments acquired	(1,433,476)	(1,139,249)	(1,909,014)
Acquisition of Family Heritage, net of cash acquired	(186,424)	0	0
Net increase in policy loans	(23,130)	(22,790)	(27,793)
Net (increase) decrease in short-term investments	(73,616)	195,435	128,727
Net change in payable or receivable for securities	3,647	2,664	(754)
Additions to properties	(4,667)	(5,386)	(9,181)
Sales of properties	56	3,089	77
Investments in low-income housing interests	(72,388)	(49,812)	(53,170)
Proceeds from sale of subsidiary	0	21,588	342,890
Cash provided from (used for) investing activities	(698,039)	(312,133)	(557,641)
Cash provided from (used for) financing activities:
Issuance of common stock	181,022	162,613	37,863
Cash dividends paid to shareholders	(55,527)	(49,125)	(50,061)
Issue expenses of debt offerings	(7,101)	0	0
Acquisition of 9 1/4% Senior Notes	0	0	(8,913)
Redemption of 7.1% Junior Subordinated Debentures	(123,711)	0	0
Net borrowing (repayment) of commercial paper	245	25,967	(34,432)
Excess tax benefit from stock option exercises	22,602	13,121	3,455
Acquisition of treasury stock	(570,165)	(972,556)	(246,006)
Net receipts (payments) from deposit product operations	8,523	(4,505)	(31,527)
Cash provided from (used for) financing activities	(269,112)	(824,485)	(329,621)
Effect of foreign exchange rate changes on cash	1,909	(4,412)	(7,570)
Increase (decrease) in cash	(22,403)	(281,566)	133,761
Cash at beginning of year (includes cash of $847 thousand at January 1, 2010 in subsidiary held for sale)	84,113	365,679	231,918
Cash at end of year	61,710	84,113	365,679
3.80% Senior Notes due 2022
Cash provided from (used for) financing activities:
Proceeds from issuance of debt	150,000	0	0
5.875% Junior subordinated debentures due 2052
Cash provided from (used for) financing activities:
Proceeds from issuance of debt	$ 125,000	$ 0	$ 0