Segment and Other Operating Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	$ 860,580	$ 848,503	$ 860,580	$ 848,503
Total segment assets	9,871,257	9,208,613	9,871,257	9,208,613
Other unallocated assets	84,204	53,817	84,204	53,817
Total condensed consolidated assets	9,955,461	9,262,430	9,955,461	9,262,430	9,727,999
Future policy benefits	8,316,731	7,699,551	8,316,731	7,699,551
Other policyholder liabilities	154,105	145,753	154,105	145,753	151,308
Condensed Consolidated Income Statements:
Premiums and contract revenues	41,557	37,239	81,839	71,093
Net investment income	78,181	97,724	227,739	231,239
Other revenues	5,866	4,698	11,521	14,604
Realized gains (losses) on investments	2,005	490	3,172	3,582
Total condensed consolidated premiums and other revenues	127,609	140,151	324,271	320,518
Total revenues	125,604	139,661	321,099	316,936
Life and other policy benefits	13,857	9,598	27,535	21,814
Amortization of deferred acquisition costs	31,349	38,848	63,060	66,337
Universal life and annuity contract interest	26,004	53,232	127,547	145,381
Other operating expenses	22,452	19,060	42,470	39,778
Federal income taxes (benefit)	9,999	5,451	19,562	13,953
Taxes on realized gains (losses) on investments	702	172	1,110	1,254
Total condensed consolidated Federal income taxes	10,701	5,623	20,672	15,207
Total expenses	103,661	126,189	280,174	287,263
Segment earnings (loss)	21,943	13,472	40,925	29,673
Realized gains (losses) on investments, net of taxes	1,303	318	2,062	2,328
Net earnings	23,246	13,790	42,987	32,001
Domestic Life Insurance [Member]
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	35,681	41,113	35,681	41,113
Total segment assets	430,613	398,712	430,613	398,712
Future policy benefits	367,968	331,037	367,968	331,037
Other policyholder liabilities	11,899	12,206	11,899	12,206
Condensed Consolidated Income Statements:
Premiums and contract revenues	4,280	6,617	14,819	12,649
Net investment income	3,991	4,485	9,809	9,481
Other revenues	45	(2)	52	5
Total revenues	8,316	11,100	24,680	22,135
Life and other policy benefits	1,620	(810)	3,268	4,424
Amortization of deferred acquisition costs	2,068	2,771	4,459	5,654
Universal life and annuity contract interest	1,230	1,849	8,443	4,487
Other operating expenses	2,578	3,361	7,346	7,027
Federal income taxes (benefit)	261	1,339	376	174
Total expenses	7,757	8,510	23,892	21,766
Segment earnings (loss)	559	2,590	788	369
International Life Insurance [Member]
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	229,034	227,166	229,034	227,166
Total segment assets	1,062,917	1,035,273	1,062,917	1,035,273
Future policy benefits	795,992	747,058	795,992	747,058
Other policyholder liabilities	13,710	16,999	13,710	16,999
Condensed Consolidated Income Statements:
Premiums and contract revenues	32,115	25,616	55,546	50,176
Net investment income	7,315	9,532	22,712	22,553
Other revenues	314	342	346	366
Total revenues	39,744	35,490	78,604	73,095
Life and other policy benefits	6,315	4,199	9,795	9,161
Amortization of deferred acquisition costs	7,757	7,927	13,365	16,125
Universal life and annuity contract interest	6,431	8,507	21,243	21,426
Other operating expenses	6,718	4,273	12,536	11,199
Federal income taxes (benefit)	3,943	3,273	7,006	4,856
Total expenses	31,164	28,179	63,945	62,767
Segment earnings (loss)	8,580	7,311	14,659	10,328
Annuities [Member]
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	595,865	580,224	595,865	580,224
Total segment assets	8,149,053	7,555,300	8,149,053	7,555,300
Future policy benefits	7,152,771	6,621,456	7,152,771	6,621,456
Other policyholder liabilities	128,496	116,548	128,496	116,548
Condensed Consolidated Income Statements:
Premiums and contract revenues	5,162	5,006	11,474	8,268
Net investment income	61,875	78,830	186,264	191,942
Other revenues	(260)	(1,070)	(199)	2,991
Total revenues	66,777	82,766	197,539	203,201
Life and other policy benefits	5,922	6,209	14,472	8,229
Amortization of deferred acquisition costs	21,524	28,150	45,236	44,558
Universal life and annuity contract interest	18,343	42,876	97,861	119,468
Other operating expenses	7,744	6,320	11,772	11,223
Federal income taxes (benefit)	4,110	(751)	9,120	6,308
Total expenses	57,643	82,804	178,461	189,786
Segment earnings (loss)	9,134	(38)	19,078	13,415
All Others [Member]
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	0	0	0	0
Total segment assets	228,674	219,328	228,674	219,328
Future policy benefits	0	0	0	0
Other policyholder liabilities		0		0
Condensed Consolidated Income Statements:
Premiums and contract revenues	0	0	0	0
Net investment income	5,000	4,877	8,954	7,263
Other revenues	5,767	5,428	11,322	11,242
Total revenues	10,767	10,305	20,276	18,505
Life and other policy benefits	0	0	0	0
Amortization of deferred acquisition costs	0	0	0	0
Universal life and annuity contract interest	0	0	0	0
Other operating expenses	5,412	5,106	10,816	10,329
Federal income taxes (benefit)	1,685	1,590	3,060	2,615
Total expenses	7,097	6,696	13,876	12,944
Segment earnings (loss)	$ 3,670	$ 3,609	$ 6,400	$ 5,561