| Document And Entity Information | Feb. 03, 2022 |
| Document Information [Line Items] | |
| Entity, Registrant Name | Natural Grocers by Vitamin Cottage, Inc. |
| Document, Type | 8-K |
| Document, Period End Date | Feb. 3, 2022 |
| Entity, Incorporation, State or Country Code | DE |
| Entity, File Number | 001-35608 |
| Entity, Tax Identification Number | 45-5034161 |
| Entity, Address, Address Line One | 12612 West Alameda Parkway |
| Entity, Address, City or Town | Lakewood |
| Entity, Address, State or Province | CO |
| Entity, Address, Postal Zip Code | 80228 |
| City Area Code | 303 |
| Local Phone Number | 986-4600 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.001 par value |
| Trading Symbol | NGVC |
| Security Exchange Name | NYSE |
| Entity, Emerging Growth Company | false |
| Amendment Flag | false |
| Entity, Central Index Key | 0001547459 |
