Document And Entity Information - USD ($)	12 Months Ended
Document And Entity Information - USD ($)	Dec. 31, 2023	Feb. 28, 2024	Jun. 30, 2023
Document Information Line Items
Entity Registrant Name	NATIONAL WESTERN LIFE GROUP, INC.
Trading Symbol	NWLI
Document Type	10-K/A
Current Fiscal Year End Date	--12-31
Entity Public Float			$ 1,063,791,213
Amendment Flag	true
Amendment Description	This Amendment No. 1 to Form 10-K (this “Amended Filing”) amends the Annual Report on Form 10-K of National Western Life Group, Inc. (the “Company,” “National Western,” “we,” “us” and “our”), for the fiscal year ended December 31, 2023, which was originally filed with the Securities and Exchange Commission (the “SEC”) on February 29, 2024 (the “Original Filing”). This Amended Filing provides the information required by Items 10, 11, 12, 13, and 14 of Part III of the Original Filing, which was omitted from the Original Filing in reliance on General Instruction G(3) to Form 10-K. Such instruction permits the information in Part III to be incorporated into the Form 10-K by reference from our definitive proxy statement, if such proxy statement is filed no later than 120 days after the end of our fiscal year. We no longer expect to file a definitive proxy statement containing this information within 120 days after the end of the fiscal year covered by the Original Filing. Accordingly, we hereby amend and restate in its entirety Part III of the Original Filing. Capitalized terms not otherwise defined in Part III of this Amended Filing shall have the respective meanings assigned to such terms in Parts I and II of the Original Filing.In addition, this Amended Filing amends Part IV, Item 15 of the Original Filing to include new certifications by our principal executive officer and principal financial officer under Section 302 of the Sarbanes-Oxley Act of 2002, as required by Rule 12b-15 under the Securities Exchange Act of 1934, as amended. Because no financial statements have been included in this Amended Filing and this Amended Filing does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4 and 5 of the certifications have been omitted. Additionally, we are not including the certification under Section 906 of the Sarbanes-Oxley Act of 2002, as no financial statements are being filed with this Amended Filing.This Amended Filing does not amend or otherwise update any other information in the Original Filing. Other than the information specifically amended and restated herein, this Amended Filing does not reflect events occurring after February 29, 2024, the date of the Original Filing, or modify or update those disclosures that may have been affected by subsequent events. Accordingly, this Amended Filing should be read in conjunction with the Original Filing and with our filings with the SEC subsequent to the Original Filing.As described in the Original Filing, on October 8, 2023, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with S. USA Life Insurance Company Inc. (“S.USA”), an insurance company formed under the laws of Arizona, and PGH Merger Sub Inc., a Delaware corporation and a wholly owned subsidiary of S. USA (“Merger Sub”). On the terms and subject to the conditions of the Merger Agreement, at the closing, Merger Sub will merge with and into the Company (the “Merger”), with the Company continuing as the surviving entity, which will become wholly owned subsidiary of S. USA. On the terms and subject to the conditions of the Merger Agreement, at the effective time of the Merger, all outstanding shares of Class A Common Stock and Class B Common Stock will be converted into the right to receive $500.00 per share in cash, without interest. Including the vesting and cash settlement of all outstanding SARs, RSUs and PSUs (at target performance) at closing, the total merger consideration to be paid by S.USA would be approximately $1.9 billion. The completion of the Merger is subject to satisfaction or waiver of certain customary closing conditions, including obtaining the required regulatory approval from the insurance authorities in Colorado, Missouri and Arizona.
Entity Central Index Key	0001635984
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Document Annual Report	true
Document Transition Report	false
Entity File Number	000-55522
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-3339380
Entity Address, Address Line One	10801 N. Mopac Expy Bldg 3
Entity Address, City or Town	Austin
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	78759
City Area Code	(512)
Local Phone Number	836-1010
Title of 12(b) Security	Class A Common Stock, $0.01 par value
Security Exchange Name	NASDAQ
Entity Interactive Data Current	Yes
Document Financial Statement Error Correction [Flag]	false
Auditor Name	FORVIS, LLP
Auditor Location	West Des Moines, Iowa
Auditor Firm ID	686
Documents Incorporated by Reference [Text Block]	None
Class A
Document Information Line Items
Entity Common Stock, Shares Outstanding		3,436,020
Class B
Document Information Line Items
Entity Common Stock, Shares Outstanding		200,000

National Western Life Group, Inc. 10-K/A