Policyholder Obligations - Account Balances by Guaranteed Minimum Interest Rates (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	$ 3,260,378	$ 3,652,095
Less than 2.00%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	1,746,496	2,158,440
2.00% - 2.99%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	641,277	597,968
3.00% - 3.99%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	496,631	497,078
4.00% and greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	375,974	398,609
At Guaranteed Minimum
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	2,956,910	3,307,459
At Guaranteed Minimum \| Less than 2.00%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	1,629,149	1,977,043
At Guaranteed Minimum \| 2.00% - 2.99%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	502,653	478,429
At Guaranteed Minimum \| 3.00% - 3.99%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	449,173	453,414
At Guaranteed Minimum \| 4.00% and greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	375,935	398,573
1-50 Basis Points Above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	45,116	51,240
1-50 Basis Points Above \| Less than 2.00%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	2,719	2,291
1-50 Basis Points Above \| 2.00% - 2.99%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	6,482	8,092
1-50 Basis Points Above \| 3.00% - 3.99%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	35,915	40,857
1-50 Basis Points Above \| 4.00% and greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	0	0
51-150 Basis Points Above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	110,741	128,390
51-150 Basis Points Above \| Less than 2.00%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	14,120	38,739
51-150 Basis Points Above \| 2.00% - 2.99%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	85,106	86,871
51-150 Basis Points Above \| 3.00% - 3.99%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	11,515	2,780
51-150 Basis Points Above \| 4.00% and greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	0	0
Greater Than 150 Basis Points Above
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	147,611	165,006
Greater Than 150 Basis Points Above \| Less than 2.00%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	100,508	140,367
Greater Than 150 Basis Points Above \| 2.00% - 2.99%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	47,036	24,576
Greater Than 150 Basis Points Above \| 3.00% - 3.99%
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	28	27
Greater Than 150 Basis Points Above \| 4.00% and greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder account balance	$ 39	$ 36

National Western Life Group, Inc. 10-Q