| Document and Entity Information | Dec. 21, 2021 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Dec. 21, 2021 |
| Entity File Number | 000-51277 |
| Entity Registrant Name | GRANITE FALLS ENERGY, LLC |
| Entity Incorporation, State or Country Code | MN |
| Entity Tax Identification Number | 41-1997390 |
| Entity Address, Address Line One | 15045 Highway 23 SE |
| Entity Address, City or Town | Granite Falls |
| Entity Address, State or Province | MN |
| Entity Address, Postal Zip Code | 56241-0216 |
| City Area Code | 320 |
| Local Phone Number | 564-3100 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | NONE |
| No Trading Symbol Flag | true |
| Security Exchange Name | NONE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001181749 |
| Amendment Flag | false |
