XML 71 R40.htm IDEA: XBRL DOCUMENT v3.25.1

Introduction and Basis of Presentation (Details)	Mar. 26, 2025 restaurant
Franchisor Disclosure [Line Items]
Number of restaurants	1,557
Denny's Brand
Franchisor Disclosure [Line Items]
Number of restaurants	1,491
Keke's
Franchisor Disclosure [Line Items]
Number of restaurants	66
Franchised/licensed Restaurants
Franchisor Disclosure [Line Items]
Number of restaurants	1,475
Franchised/licensed Restaurants | Denny's Brand
Franchisor Disclosure [Line Items]
Number of restaurants	1,430
Franchised/licensed Restaurants | Keke's
Franchisor Disclosure [Line Items]
Number of restaurants	45
Company Restaurants
Franchisor Disclosure [Line Items]
Number of restaurants	82
Company Restaurants | Denny's Brand
Franchisor Disclosure [Line Items]
Number of restaurants	61
Company Restaurants | Keke's
Franchisor Disclosure [Line Items]
Number of restaurants	21

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FranchisorDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Represents the number of restaurants.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfRestaurants
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	dei_LegalEntityAxis=denn_DennysBrandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=denn_KekesBreakfastCafeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FranchisorDisclosureAxis=us-gaap_FranchisedUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FranchisorDisclosureAxis=us-gaap_EntityOperatedUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: