v3.25.2
Cover Page - shares
 6 Months Ended
Jun. 25, 2025
Jul. 30, 2025
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 25, 2025  
Document Transition Report false  
Entity File Number 0-18051  
Entity Registrant Name DENNY’S CORPORATION  
Entity Incorporation, State or Country Code DE  
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  
Title of 12(b) Security $.01 Par Value, Common Stock  
Trading Symbol DENN  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   51,498,994
Entity Central Index Key 0000852772  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q2  
Amendment Flag false