XML 159 R82.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Long-Term Debt - Schedule of Interest Rate Swaps (Details) - USD ($) | Mar. 31, 2025 | Dec. 25, 2024
--- | --- | ---
Derivative [Line Items] |  |
Notional Amount |  | $ 238,000,000
Fair Value |  | 20,841,000
Interest Rate Swaps Maturity 2025 |  |
Derivative [Line Items] |  |
Notional Amount |  | 120,000,000
Fair Value |  | $ 618,000
Fixed Rate |  | 2.34%
Interest Rate Swaps Maturity 2026 |  |
Derivative [Line Items] |  |
Notional Amount |  | $ 50,000,000
Fair Value |  | $ 1,087,000
Fixed Rate |  | 2.37%
Interest Rate Swaps Maturity 2033 |  |
Derivative [Line Items] |  |
Notional Amount |  | $ 68,000,000
Fair Value |  | $ 19,136,000
Fixed Rate |  | 3.09%
Interest Rate Swaps Maturity 2033 | Forecast |  |
Derivative [Line Items] |  |
Notional Amount | $ 120,000,000 |
Maximum | Interest Rate Swaps Maturity 2033 |  |
Derivative [Line Items] |  |
Notional Amount |  | $ 335,000,000

X
- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 + Details
Name: | us-gaap_DerivativeFairValueOfDerivativeNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fixed interest rate related to the interest rate derivative. + References No definition available. + Details
Name: | us-gaap_DerivativeFixedInterestRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480237/815-40-50-5 + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-1B Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-1A + Details
Name: | us-gaap_DerivativeNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=denn_InterestRateSwaps20182025Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=denn_InterestRateSwaps20182026Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=denn_InterestRateSwap20202033Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |