Segment and Other Operating Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Selected Condensed Consolidated Balance Sheet Items:
Total segment assets	$ 10,912,617	$ 10,476,501	$ 10,830,416
Other policyholder liabilities	143,738		142,587
Condensed Consolidated Income Statements:
Premiums and contract revenues	42,276	41,763
Net investment income	108,451	180,814
Other revenues	5,763	6,142
Realized gains (losses) on investments	1,513	2,313
Total condensed consolidated premiums and other revenues	158,003	231,032
Life and other policy benefits	12,963	12,690
Amortization of deferred acquisition costs	28,579	30,804
Universal life and annuity contract interest	62,936	140,300
Other operating expenses	23,463	21,924
Federal income taxes (benefit)	9,706	7,872
Taxes on realized gains (losses) on investments	530	810
Total condensed consolidated Federal income taxes	10,236	8,682
Segment earnings (loss)	18,843	15,129
Realized gains (losses) on investments, net of taxes	983	1,503
Net earnings	19,826	16,632
Segments [Member]
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	937,779	864,002
Total segment assets	10,714,485	10,321,396
Future policy benefits	9,157,868	8,725,381
Other policyholder liabilities	143,738	155,482
Condensed Consolidated Income Statements:
Premiums and contract revenues	42,276	41,763
Net investment income	108,451	180,814
Other revenues	5,763	6,142
Total condensed consolidated premiums and other revenues	156,490	228,719
Life and other policy benefits	12,963	12,690
Amortization of deferred acquisition costs	28,579	30,804
Universal life and annuity contract interest	62,936	140,300
Other operating expenses	23,463	21,924
Federal income taxes (benefit)	9,706	7,872
Total expenses	137,647	213,590
Segment earnings (loss)	18,843	15,129
Segments [Member] | Domestic Life Insurance [Member]
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	53,815	41,026
Total segment assets	634,334	496,778
Future policy benefits	554,247	427,006
Other policyholder liabilities	11,867	12,547
Condensed Consolidated Income Statements:
Premiums and contract revenues	8,165	9,610
Net investment income	6,283	7,773
Other revenues	18	12
Total condensed consolidated premiums and other revenues	14,466	17,395
Life and other policy benefits	2,492	3,030
Amortization of deferred acquisition costs	2,400	2,035
Universal life and annuity contract interest	5,105	7,191
Other operating expenses	4,279	3,767
Federal income taxes (benefit)	65	470
Total expenses	14,341	16,493
Segment earnings (loss)	125	902
Segments [Member] | International Life Insurance [Member]
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	239,432	227,263
Total segment assets	1,188,473	1,148,773
Future policy benefits	920,665	861,854
Other policyholder liabilities	15,587	10,139
Condensed Consolidated Income Statements:
Premiums and contract revenues	29,108	28,019
Net investment income	10,718	18,630
Other revenues	241	43
Total condensed consolidated premiums and other revenues	40,067	46,692
Life and other policy benefits	5,035	3,645
Amortization of deferred acquisition costs	6,745	5,787
Universal life and annuity contract interest	10,205	21,991
Other operating expenses	7,025	6,708
Federal income taxes (benefit)	3,759	2,930
Total expenses	32,769	41,061
Segment earnings (loss)	7,298	5,631
Segments [Member] | Annuities [Member]
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	644,532	595,713
Total segment assets	8,627,243	8,418,536
Future policy benefits	7,682,956	7,436,521
Other policyholder liabilities	116,284	132,796
Condensed Consolidated Income Statements:
Premiums and contract revenues	5,003	4,134
Net investment income	86,617	150,378
Other revenues	37	39
Total condensed consolidated premiums and other revenues	91,657	154,551
Life and other policy benefits	5,436	6,015
Amortization of deferred acquisition costs	19,434	22,982
Universal life and annuity contract interest	47,626	111,118
Other operating expenses	7,096	6,086
Federal income taxes (benefit)	4,102	2,857
Total expenses	83,694	149,058
Segment earnings (loss)	7,963	5,493
Segments [Member] | All Others [Member]
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs and sales inducements	0	0
Total segment assets	264,435	257,309
Future policy benefits	0	0
Other policyholder liabilities	0	0
Condensed Consolidated Income Statements:
Premiums and contract revenues	0	0
Net investment income	4,833	4,033
Other revenues	5,467	6,048
Total condensed consolidated premiums and other revenues	10,300	10,081
Life and other policy benefits	0	0
Amortization of deferred acquisition costs	0	0
Universal life and annuity contract interest	0	0
Other operating expenses	5,063	5,363
Federal income taxes (benefit)	1,780	1,615
Total expenses	6,843	6,978
Segment earnings (loss)	3,457	3,103
Other unallocated [Member]
Selected Condensed Consolidated Balance Sheet Items:
Total segment assets	$ 198,132	$ 155,105