Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Nov. 02, 2017
Entity Information [Line Items]
Entity Registrant Name	NATIONAL WESTERN LIFE GROUP, INC.
Entity Central Index Key	0001635984
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q3
Amendment Flag	false
Class A
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		3,436,166
Class B
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		200,000