| Cover Page | Sep. 30, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Sep. 30, 2020 |
| Entity Registrant Name | DENNY’S CORPORATION |
| Entity Central Index Key | 0000852772 |
| Amendment Flag | false |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 0-18051 |
| Entity Tax Identification Number | 13-3487402 |
| Entity Address, Address Line One | 203 East Main Street |
| Entity Address, City or Town | Spartanburg |
| Entity Address, State or Province | SC |
| Entity Address, Postal Zip Code | 29319-0001 |
| City Area Code | 864 |
| Local Phone Number | 597-8000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | $.01 Par Value, Common Stock |
| Trading Symbol | DENN |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
