Segment and Other Operating Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	$ 849,222	$ 866,548	$ 849,222	$ 866,548
Total segment assets	10,103,615	9,439,462	10,103,615	9,439,462
Other unallocated assets	62,479	62,680	62,479	62,680
Total condensed consolidated assets	10,166,094	9,502,142	10,166,094	9,502,142	9,727,999
Future policy benefits	8,467,600	7,911,911	8,467,600	7,911,911
Other policyholder liabilities	152,725	148,384	152,725	148,384	151,308
Condensed Consolidated Income Statements:
Premiums and contract revenues	41,048	39,235	122,887	110,328
Net investment income	139,074	44,538	366,813	275,777
Other revenues	5,923	5,643	17,444	20,247
Realized gains (losses) on investments	4,940	2,938	8,112	6,520
Total condensed consolidated premiums and other revenues	190,985	92,354	515,256	412,872
Total revenues	186,045	89,416	507,144	406,352
Life and other policy benefits	12,323	12,363	39,858	34,177
Amortization of deferred acquisition costs	28,403	29,909	91,463	96,246
Universal life and annuity contract interest	89,386	1,873	216,933	147,254
Other operating expenses	22,143	18,948	64,613	58,727
Federal income taxes (benefit)	12,679	8,968	32,241	22,921
Taxes on realized gains (losses) on investments	1,729	1,028	2,839	2,282
Total condensed consolidated Federal income taxes	14,408	9,996	35,080	25,203
Total expenses	164,934	72,061	445,108	359,325
Segment earnings (loss)	21,111	17,355	62,036	47,027
Realized gains (losses) on investments, net of taxes	3,211	1,910	5,273	4,238
Net earnings	24,322	19,265	67,309	51,265
Domestic Life Insurance [Member]
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	38,052	40,676	38,052	40,676
Total segment assets	450,649	401,243	450,649	401,243
Future policy benefits	380,752	335,100	380,752	335,100
Other policyholder liabilities	13,401	13,883	13,401	13,883
Condensed Consolidated Income Statements:
Premiums and contract revenues	7,680	8,345	22,499	20,994
Net investment income	6,037	1,655	15,846	11,136
Other revenues	(46)	3	6	8
Total revenues	13,671	10,003	38,351	32,138
Life and other policy benefits	4,482	2,151	7,750	6,575
Amortization of deferred acquisition costs	437	2,791	4,896	8,445
Universal life and annuity contract interest	2,976	2,848	11,419	7,335
Other operating expenses	3,313	2,426	10,659	9,453
Federal income taxes (benefit)	865	(66)	1,241	108
Total expenses	12,073	10,150	35,965	31,916
Segment earnings (loss)	1,598	(147)	2,386	222
International Life Insurance [Member]
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	224,814	229,656	224,814	229,656
Total segment assets	1,111,039	1,034,324	1,111,039	1,034,324
Future policy benefits	821,178	744,862	821,178	744,862
Other policyholder liabilities	11,536	17,567	11,536	17,567
Condensed Consolidated Income Statements:
Premiums and contract revenues	28,453	25,375	83,999	75,551
Net investment income	12,255	3,253	34,967	25,806
Other revenues	32	(20)	378	346
Total revenues	40,740	28,608	119,344	101,703
Life and other policy benefits	4,827	4,737	14,622	13,898
Amortization of deferred acquisition costs	2,083	8,249	15,448	24,374
Universal life and annuity contract interest	9,602	766	30,845	22,192
Other operating expenses	7,069	4,353	19,605	15,552
Federal income taxes (benefit)	6,271	3,561	13,277	8,417
Total expenses	29,852	21,666	93,797	84,433
Segment earnings (loss)	10,888	6,942	25,547	17,270
Annuities [Member]
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	586,356	596,216	586,356	596,216
Total segment assets	8,302,668	7,784,519	8,302,668	7,784,519
Future policy benefits	7,265,670	6,831,949	7,265,670	6,831,949
Other policyholder liabilities	127,788	116,934	127,788	116,934
Condensed Consolidated Income Statements:
Premiums and contract revenues	4,915	5,515	16,389	13,783
Net investment income	115,781	33,940	302,045	225,882
Other revenues	213	152	14	3,143
Total revenues	120,909	39,607	318,448	242,808
Life and other policy benefits	3,014	5,475	17,486	13,704
Amortization of deferred acquisition costs	25,883	18,869	71,119	63,427
Universal life and annuity contract interest	76,808	(1,741)	174,669	117,727
Other operating expenses	7,332	7,059	19,104	18,282
Federal income taxes (benefit)	3,215	3,414	12,335	9,722
Total expenses	116,252	33,076	294,713	222,862
Segment earnings (loss)	4,657	6,531	23,735	19,946
All Others [Member]
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	0	0	0	0
Total segment assets	239,259	219,376	239,259	219,376
Future policy benefits	0	0	0	0
Other policyholder liabilities	0	0	0	0
Condensed Consolidated Income Statements:
Premiums and contract revenues	0	0	0	0
Net investment income	5,001	5,690	13,955	12,953
Other revenues	5,724	5,508	17,046	16,750
Total revenues	10,725	11,198	31,001	29,703
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	4,429	5,110	15,245	15,440
Federal income taxes (benefit)	2,328	2,059	5,388	4,674
Total expenses	6,757	7,169	20,633	20,114
Segment earnings (loss)	$ 3,968	$ 4,029	$ 10,368	$ 9,589