Statutory Information - Statutory Accounting Practices (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
National Western Life Insurance Company:
Statutory Accounting Practices [Line Items]
Net gain from operations before Federal and foreign income taxes	$ 85,440	$ 1,423	$ 209,139
Net income	63,476	6,487	151,316
Unassigned surplus	1,536,112	1,461,100	1,485,424
Capital and surplus	1,580,176	1,505,163	1,529,487
Ozark National Life Insurance Company:
Statutory Accounting Practices [Line Items]
Net gain from operations before Federal and foreign income taxes	23,103	24,976	22,870
Net income	28,183	20,966	(854)
Unassigned surplus	77,806	50,054	29,452
Capital and surplus	$ 105,761	$ 78,009	$ 58,404