Business Segments - Segment Premium Income by Distribution Channel and Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) segment	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting [Abstract]
Number of segments | segment	4
Segment Reporting Information [Line Items]
Revenue	$ 4,099,887	$ 3,813,905	$ 3,595,134
% of Total	100.00%	100.00%	100.00%
Life
Segment Reporting Information [Line Items]
Revenue	$ 2,898,210	$ 2,672,804	$ 2,517,784
% of Total	100.00%	100.00%	100.00%
Health
Segment Reporting Information [Line Items]
Revenue	$ 1,201,676	$ 1,141,097	$ 1,077,346
% of Total	100.00%	100.00%	100.00%
Annuity
Segment Reporting Information [Line Items]
Revenue	$ 1	$ 4	$ 4
% of Total	100.00%	100.00%	100.00%
American Income
Segment Reporting Information [Line Items]
Revenue	$ 1,517,828	$ 1,363,460	$ 1,259,942
% of Total	37.00%	36.00%	35.00%
American Income | Life
Segment Reporting Information [Line Items]
Revenue	$ 1,402,878	$ 1,257,726	$ 1,160,495
% of Total	48.00%	47.00%	46.00%
American Income | Health
Segment Reporting Information [Line Items]
Revenue	$ 114,950	$ 105,734	$ 99,447
% of Total	9.00%	9.00%	9.00%
American Income | Annuity
Segment Reporting Information [Line Items]
Revenue	$ 0	$ 0	$ 0
% of Total	0.00%	0.00%	0.00%
Direct to Consumer
Segment Reporting Information [Line Items]
Revenue	$ 1,045,407	$ 983,486	$ 933,100
% of Total	25.00%	26.00%	26.00%
Direct to Consumer | Life
Segment Reporting Information [Line Items]
Revenue	$ 971,461	$ 906,959	$ 855,543
% of Total	34.00%	34.00%	34.00%
Direct to Consumer | Health
Segment Reporting Information [Line Items]
Revenue	$ 73,946	$ 76,527	$ 77,557
% of Total	6.00%	7.00%	7.00%
Direct to Consumer | Annuity
Segment Reporting Information [Line Items]
Revenue	$ 0	$ 0	$ 0
% of Total	0.00%	0.00%	0.00%
Liberty National
Segment Reporting Information [Line Items]
Revenue	$ 498,408	$ 482,732	$ 475,129
% of Total	12.00%	13.00%	13.00%
Liberty National | Life
Segment Reporting Information [Line Items]
Revenue	$ 311,081	$ 293,897	$ 285,551
% of Total	11.00%	11.00%	11.00%
Liberty National | Health
Segment Reporting Information [Line Items]
Revenue	$ 187,327	$ 188,835	$ 189,578
% of Total	16.00%	16.00%	18.00%
Liberty National | Annuity
Segment Reporting Information [Line Items]
Revenue	$ 0	$ 0	$ 0
% of Total	0.00%	0.00%	0.00%
United American
Segment Reporting Information [Line Items]
Revenue	$ 490,437	$ 462,672	$ 427,157
% of Total	12.00%	12.00%	12.00%
United American | Life
Segment Reporting Information [Line Items]
Revenue	$ 8,822	$ 9,688	$ 10,571
% of Total	0.00%	0.00%	1.00%
United American | Health
Segment Reporting Information [Line Items]
Revenue	$ 481,614	$ 452,980	$ 416,582
% of Total	40.00%	40.00%	39.00%
United American | Annuity
Segment Reporting Information [Line Items]
Revenue	$ 1	$ 4	$ 4
% of Total	100.00%	100.00%	100.00%
Family Heritage
Segment Reporting Information [Line Items]
Revenue	$ 348,796	$ 321,274	$ 298,012
% of Total	9.00%	8.00%	8.00%
Family Heritage | Life
Segment Reporting Information [Line Items]
Revenue	$ 4,957	$ 4,253	$ 3,830
% of Total	0.00%	0.00%	0.00%
Family Heritage | Health
Segment Reporting Information [Line Items]
Revenue	$ 343,839	$ 317,021	$ 294,182
% of Total	29.00%	28.00%	27.00%
Family Heritage | Annuity
Segment Reporting Information [Line Items]
Revenue	$ 0	$ 0	$ 0
% of Total	0.00%	0.00%	0.00%
Other
Segment Reporting Information [Line Items]
Revenue	$ 199,011	$ 200,281	$ 201,794
% of Total	5.00%	5.00%	6.00%
Other | Life
Segment Reporting Information [Line Items]
Revenue	$ 199,011	$ 200,281	$ 201,794
% of Total	7.00%	8.00%	8.00%
Other | Health
Segment Reporting Information [Line Items]
Revenue	$ 0	$ 0	$ 0
% of Total	0.00%	0.00%	0.00%
Other | Annuity
Segment Reporting Information [Line Items]
Revenue	$ 0	$ 0	$ 0
% of Total	0.00%	0.00%	0.00%