Segment and Other Operating Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Selected Condensed Consolidated Balance Sheet Items:
Total assets	$ 12,420,986		$ 12,420,986		$ 12,553,447
Other policyholder liabilities	136,392		136,392		127,607
Condensed Consolidated Income Statements:
Premiums and contract revenues	62,996	$ 61,939	181,434	$ 178,195
Net investment income (loss)	129,679	108,456	261,894	388,211
Other revenues	3,977	3,273	15,217	13,652
Realized gains (losses) on investments	6,050	(502)	12,660	3,702
Total revenues	202,702	173,166	471,205	583,760
Life and other policy benefits	26,940	39,918	94,005	101,764
Amortization of deferred policy acquisition costs and value of business acquired	50,800	22,998	111,937	86,573
Universal life and annuity contract interest	85,879	59,445	119,625	200,500
Other operating expenses	25,754	25,813	74,730	77,196
Federal income taxes (benefit)	2,504	5,003	13,732	23,844
Net earnings	10,825	19,989	57,176	93,883
Segments
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs, sales inducements, and value of business acquired	851,879		851,879		966,402
Total assets	11,711,852		11,711,852		12,092,796
Future policy benefits	9,862,176		9,862,176		10,141,971
Other policyholder liabilities	136,392		136,392		127,607
Condensed Consolidated Income Statements:
Premiums and contract revenues	62,996	61,939	181,434	178,195
Net investment income (loss)	129,679	108,456	261,894	388,211
Other revenues	3,977	3,273	15,217	13,652
Total revenues	196,652	173,668	458,545	580,058
Life and other policy benefits	26,940	39,918	94,005	101,764
Amortization of deferred policy acquisition costs and value of business acquired	50,800	22,998	111,937	86,573
Universal life and annuity contract interest	85,879	59,445	119,625	200,500
Other operating expenses	25,754	25,813	74,730	77,196
Federal income taxes (benefit)	1,233	5,109	11,073	23,067
Total expenses	190,606	153,283	411,370	489,100
Net earnings	6,046	20,385	47,175	90,958
Segments | Domestic Life Insurance
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs, sales inducements, and value of business acquired	127,124		127,124		127,557
Total assets	1,467,577		1,467,577		1,399,818
Future policy benefits	1,275,476		1,275,476		1,198,103
Other policyholder liabilities	17,190		17,190		18,016
Condensed Consolidated Income Statements:
Premiums and contract revenues	17,734	11,387	40,971	32,897
Net investment income (loss)	21,201	12,885	23,293	51,379
Other revenues	10	49	40	113
Total revenues	38,945	24,321	64,304	84,389
Life and other policy benefits	3,785	6,099	13,831	13,850
Amortization of deferred policy acquisition costs and value of business acquired	10,540	2,181	16,322	8,898
Universal life and annuity contract interest	20,352	11,267	17,831	45,693
Other operating expenses	5,185	5,297	15,123	14,437
Federal income taxes (benefit)	(161)	(107)	199	306
Total expenses	39,701	24,737	63,306	83,184
Net earnings	(756)	(416)	998	1,205
Segments | International Life Insurance
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs, sales inducements, and value of business acquired	183,318		183,318		209,858
Total assets	1,049,371		1,049,371		1,153,105
Future policy benefits	798,665		798,665		870,461
Other policyholder liabilities	12,214		12,214		14,903
Condensed Consolidated Income Statements:
Premiums and contract revenues	21,551	25,065	67,479	74,905
Net investment income (loss)	10,354	6,872	12,507	30,165
Other revenues	6	25	54	79
Total revenues	31,911	31,962	80,040	105,149
Life and other policy benefits	2,278	5,074	9,293	10,195
Amortization of deferred policy acquisition costs and value of business acquired	6,496	(3,047)	19,392	11,195
Universal life and annuity contract interest	(14,023)	14,637	(15,368)	33,967
Other operating expenses	5,434	5,493	13,047	14,278
Federal income taxes (benefit)	5,169	1,970	8,907	7,192
Total expenses	5,354	24,127	35,271	76,827
Net earnings	26,557	7,835	44,769	28,322
Segments | Annuities
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs, sales inducements, and value of business acquired	402,072		402,072		486,553
Total assets	7,797,137		7,797,137		8,198,730
Future policy benefits	7,068,118		7,068,118		7,366,894
Other policyholder liabilities	91,818		91,818		80,002
Condensed Consolidated Income Statements:
Premiums and contract revenues	4,187	5,336	13,536	16,061
Net investment income (loss)	87,889	78,000	196,187	270,727
Other revenues	84	8	80	80
Total revenues	92,160	83,344	209,803	286,868
Life and other policy benefits	3,383	12,550	20,452	33,856
Amortization of deferred policy acquisition costs and value of business acquired	31,794	21,688	70,159	60,150
Universal life and annuity contract interest	79,550	33,541	117,162	120,840
Other operating expenses	9,205	8,596	28,787	25,478
Federal income taxes (benefit)	(5,294)	1,388	(4,440)	9,426
Total expenses	118,638	77,763	232,120	249,750
Net earnings	(26,478)	5,581	(22,317)	37,118
Segments | Acquired Businesses
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs, sales inducements, and value of business acquired	139,365		139,365		142,434
Total assets	1,030,162		1,030,162		978,243
Future policy benefits	719,917		719,917		706,513
Other policyholder liabilities	15,170		15,170		14,686
Condensed Consolidated Income Statements:
Premiums and contract revenues	19,524	20,151	59,448	54,332
Net investment income (loss)	6,434	6,300	19,284	16,283
Other revenues	2,628	2,318	7,369	6,049
Total revenues	28,586	28,769	86,101	76,664
Life and other policy benefits	17,494	16,195	50,429	43,863
Amortization of deferred policy acquisition costs and value of business acquired	1,970	2,176	6,064	6,330
Universal life and annuity contract interest	0	0	0	0
Other operating expenses	4,498	4,772	13,361	12,348
Federal income taxes (benefit)	963	1,133	4,103	2,836
Total expenses	24,925	24,276	73,957	65,377
Net earnings	3,661	4,493	12,144	11,287
Segments | All Others
Selected Condensed Consolidated Balance Sheet Items:
Deferred policy acquisition costs, sales inducements, and value of business acquired	0		0		0
Total assets	367,605		367,605		362,900
Future policy benefits	0		0		0
Other policyholder liabilities	0		0		0
Condensed Consolidated Income Statements:
Premiums and contract revenues	0	0	0	0
Net investment income (loss)	3,801	4,399	10,623	19,657
Other revenues	1,249	873	7,674	7,331
Total revenues	5,050	5,272	18,297	26,988
Life and other policy benefits	0	0	0	0
Amortization of deferred policy acquisition costs and value of business acquired	0	0	0	0
Universal life and annuity contract interest	0	0	0	0
Other operating expenses	1,432	1,655	4,412	10,655
Federal income taxes (benefit)	556	725	2,304	3,307
Total expenses	1,988	2,380	6,716	13,962
Net earnings	3,062	2,892	11,581	13,026
Other unallocated
Selected Condensed Consolidated Balance Sheet Items:
Total assets	709,134		709,134		460,651
Segment Reconciling Items
Condensed Consolidated Income Statements:
Taxes on realized gains (losses) on investments	1,271	(106)	2,659	777
Realized gains (losses) on investments, net of taxes	$ 4,779	$ (396)	$ 10,001	$ 2,925
Restatement Adjustment
Selected Condensed Consolidated Balance Sheet Items:
Future policy benefits					$ 15,000