Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Mar. 19, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K/A
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	0-18649
Entity Registrant Name	National Security Group, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	63-1020300
Entity Address, Address Line One	661 East Davis Street
Entity Address, City or Town	Elba,
Entity Address, State or Province	AL
Entity Address, Postal Zip Code	36323
City Area Code	334
Local Phone Number	897-2273
Title of 12(b) Security	Common Stock, par value $1.00 per share
Trading Symbol	NSEC
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 14,228,029
Entity Common Stock, Shares Outstanding		2,530,370
Documents Incorporated by Reference	Definitive proxy statement for the 2021 Annual Meeting of Stockholders to be held May 21, 2021 is incorporated by reference into Part III of this report. The proxy statement will be filed no later than 120 days from December 31, 2020.ii.Current Report on Form 8-K for event occurring on February 26, 2021 is incorporated into Part IV of this report.
Entity Central Index Key	0000865058
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false