The retention amount of Catastrophe reinsurance agreement contracts.

No definition available.

Name:	dgica_CatastropheReinsuranceAgreementContractsRetentionAmount
Namespace Prefix:	dgica_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Infrastructure related costs allocated to insurance subsidiaries.

+ References

No definition available.

+ Details

Name:	dgica_InfrastructureRelatedCostsAllocatedToInsuranceSubsidiaries
Namespace Prefix:	dgica_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The maximum amount of loss coverage under reinsurance agreement of property catastrophe.

+ References

No definition available.

+ Details

Name:	dgica_MaximumAmountOfLossCoverageUnderReinsuranceAgreementOfPropertyCatastrophe
Namespace Prefix:	dgica_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The percentage of premium and losses related to reinsurance

+ References

No definition available.

+ Details

Name:	dgica_PercentageOfPremiumAndLossesRelatedToReinsurance
Namespace Prefix:	dgica_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of share in results of pooled business owned by third party.

+ References

No definition available.

+ Details

Name:	dgica_PercentageOfShareInResultsOfPooledBusinessOwnedByThirdParty
Namespace Prefix:	dgica_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of share in results of pooled business subsidiary.

+ References

No definition available.

+ Details

Name:	dgica_PercentageOfShareInResultsOfPooledBusinessSubsidiary
Namespace Prefix:	dgica_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Proportionate share of the remaining infrastructure costs.

+ References

No definition available.

+ Details

Name:	dgica_ProportionateShareOfRemainingInfrastructureCosts
Namespace Prefix:	dgica_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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 944
-SubTopic 825
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477351/944-825-50-1B

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 825
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477351/944-825-50-1B

+ Details

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

- Definition

The expense incurred by an insurance company to persons or entities for generating or placing insurance or investment contracts with the company, usually determined as a percentage of policy or contract premiums. Excludes advances or draws to be applied against commissions earned.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(7)(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1

+ Details

Name:	us-gaap_InsuranceCommissions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

+ Details

Name:	us-gaap_LesseeOperatingLeaseTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

The charge against earnings in the period for the uninsured portion of a loss from a fire, explosion, or natural disaster (hurricane, earthquake).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(9))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

+ Details

Name:	us-gaap_LossFromCatastrophes
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of assumed premium earned to premium earned after effects of reinsurance, as disclosed in supplementary reinsurance information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 235
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.12-17(Column F))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477965/944-235-S99-2

+ Details

Name:	us-gaap_PremiumsPercentageAssumedToNet
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Details

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

- Details

Name:	srt_ConsolidatedEntitiesAxis=dgica_DonegalMutualInsuranceCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_OfficeEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=us-gaap_ProfessionalLiabilityInsuranceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Transactions with Affiliates (Details) - USD ($)	12 Months Ended
Transactions with Affiliates (Details) - USD ($)	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Transactions with Affiliates [Abstract]
Premiums and losses related to certain products	67.00%	65.30%	66.20%
Atlantic States [Member]
Transactions with Affiliates [Abstract]
Percentage of share in results of pooled business subsidiary	80.00%
Insurance Subsidiaries [Member]
Transactions with Affiliates [Abstract]
Coverage under catastrophic occurrence	$ 6,000,000	$ 6,000,000	$ 6,000,000
Donegal Mutual [Member]
Transactions with Affiliates [Abstract]
Premiums and losses related to certain products	100.00%
Percentage of share in results of pooled business owned by third party	20.00%
Premiums and losses related to business of MICO	25.00%
Coverage under catastrophic occurrence	$ 3,000,000	3,000,000	3,000,000
Charges for services	224,811,543	224,565,390	218,974,132
Infrastructure related costs allocated	11,300,000	$ 12,300,000	$ 10,500,000
Proportionate share of the remaining infrastructure costs	$ 45,600,000
Minimum [Member] \| Office Equipment [Member]
Transactions with Affiliates [Abstract]
Lease agreement term	3 years
Maximum [Member] \| Office Equipment [Member]
Transactions with Affiliates [Abstract]
Lease agreement term	10 years
Liability Insurance [Member]
Transactions with Affiliates [Abstract]
Maximum amount of loss coverage under reinsurance agreement of property catastrophe	$ 69,000,000
Catastrophe reinsurance, set retention amount	6,000,000
Liability Insurance [Member] \| Donegal Mutual [Member]
Transactions with Affiliates [Abstract]
Maximum amount of loss coverage under reinsurance agreement of property catastrophe	3,000,000
Catastrophe reinsurance, set retention amount	$ 3,000,000