| Cover | Mar. 04, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Mar. 4, 2022 |
| Entity Registrant Name | NATIONAL SECURITY GROUP, INC |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 0-18649 |
| 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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $1.00 per share |
| Trading Symbol | NSEC |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000865058 |
| Amendment Flag | false |
