Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net income	$ 528,472	$ 529,324	$ 497,161
Adjustments to reconcile net income to cash provided from operations:
Increase in future policy benefits	578,217	497,306	431,362
Increase (decrease) in other policy benefits	(6,006)	(8,115)	(2,776)
Deferral of policy acquisition costs	(524,263)	(480,818)	(441,825)
Amortization of deferred policy acquisition costs	403,389	385,167	364,583
Change in current and deferred income taxes	76,121	122,538	30,899
Realized (gains) losses on sale of investments and properties	(7,990)	(37,833)	(25,904)
Change in other receivables	50,900	(89,677)	(22,565)
Loss on disposal of subsidiary	0	0	455
Other, net	20,440	24,947	28,074
Cash provided from operations	1,119,280	942,839	859,464
Investments sold or matured:
Fixed maturities available for sale-sold	133,463	345,601	224,335
Fixed maturities available for sale-matured, called, and repaid	493,885	736,900	410,356
Equity securities	14,000	0	28,700
Other long-term investments	1,333	9,458	18,937
Total investments sold or matured	642,681	1,091,959	682,328
Acquisition of investments:
Fixed maturities-available for sale	(1,143,840)	(1,431,690)	(1,104,231)
Equity securities	0	0	(28,772)
Other long-term investments	(591)	(1,786)	(6,246)
Total investments acquired	(1,144,431)	(1,433,476)	(1,139,249)
Acquisition of Family Heritage, net of cash acquired	0	(186,424)	0
Net increase in policy loans	(24,837)	(23,130)	(22,790)
Net (increase) decrease in short-term investments	17,970	(73,616)	195,435
Net change in payable or receivable for securities	(43,987)	3,647	2,664
Additions to properties	(11,168)	(4,667)	(5,386)
Sales of properties	570	56	3,089
Investments in low-income housing interests	(51,176)	(72,388)	(49,812)
Proceeds from sale of subsidiary	0	0	21,588
Cash provided from (used for) investing activities	(614,378)	(698,039)	(312,133)
Cash provided from (used for) financing activities:
Issuance of common stock	97,816	181,022	162,613
Cash dividends paid to shareholders	(60,911)	(55,527)	(49,125)
Issue expenses of debt offerings	0	(7,101)	0
Net borrowing (repayment) of commercial paper	3,983	245	25,967
Excess tax benefit from stock option exercises	21,315	22,602	13,121
Acquisition of treasury stock	(482,264)	(570,165)	(972,556)
Net receipts (payments) from deposit-type product	(21,808)	8,523	(4,505)
Cash provided from (used for) financing activities	(535,919)	(269,112)	(824,485)
Effect of foreign exchange rate changes on cash	6,250	1,909	(4,412)
Increase (decrease) in cash	(24,767)	(22,403)	(281,566)
Cash at beginning of year	61,710	84,113	365,679
Cash at end of year	36,943	61,710	84,113
3.80% Senior Notes due 2022 [Member]
Cash provided from (used for) financing activities:
Proceeds from issuance of debt	0	150,000	0
5.875% Junior subordinated debentures due 2052 [Member]
Cash provided from (used for) financing activities:
Proceeds from issuance of debt	0	125,000	0
7.375% Notes [Member]
Cash provided from (used for) financing activities:
Repayment of Notes	(94,050)	0	0
7.1% Junior Subordinated Debentures [Member]
Cash provided from (used for) financing activities:
Redemption of Junior Subordinated Debentures	$ 0	$ (123,711)	$ 0