Document and Entity Information	9 Months Ended
	Sep. 30, 2012	Nov. 07, 2012 Common Class A [Member]	Nov. 07, 2012 Common Class B [Member]
Entity Information [Line Items]
Entity Registrant Name	NATIONAL WESTERN LIFE INSURANCE CO
Entity Central Index Key	0000070684
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		3,434,763	200,000