Contracts in force subject to participation through reinsurance value per occurrence.

No definition available.

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Period Type:	duration

- Definition

Maximum amount of loss coverage under reinsurance agreement of property catastrophe.

+ References

No definition available.

+ Details

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

- Definition

Quota share reinsurance percentage.

+ References

No definition available.

+ Details

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Namespace Prefix:	dgica_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Quota share reinsurance reduced percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	dgica_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:	dgica_
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Balance Type:	na
Period Type:	duration

- Definition

Reinsurance treaty coverage percentage minimum.

+ References

No definition available.

+ Details

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Namespace Prefix:	dgica_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Ratio of insurance contracts that are subject to reinsurance participation to all contracts in force.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The value of insurance contracts that are subject to reinsurance participation agreements (risk assumed from other insurers).

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 8, 9

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.9)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of obligations and payables pertaining to claims incurred of a workers compensation nature. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Reinsurance (Details Textual) (USD $)	12 Months Ended
Reinsurance (Details Textual) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Ceded Credit Risk [Line Items]
Excess of loss reinsured under an agreement	$ 1,000,000
Percentage of accumulation of losses	50.00%
Quota share reinsurance percentage		50.00%	75.00%
Reinsurance (Textual) [Abstract]
Natural disasters, over a set retention	5,000,000
Workers' compensation insurance	10,000,000
Percentage of reinsurer coverage	36.00%
Donegal Mutual [Member]
Ceded Credit Risk [Line Items]
Percentage of accumulation of losses	25.00%
Maximum amount of loss coverage under reinsurance agreement of property catastrophe	135,000,000
Insurance Subsidiaries [Member]
Ceded Credit Risk [Line Items]
Excess of loss reinsured under an agreement	5,000,000
Excess of loss treaties	40,000,000
Minimum [Member]
Ceded Credit Risk [Line Items]
Percentage of accumulation of losses	90.00%
Quota share reinsurance reduced percentage	30.00%	40.00%
Maximum [Member]
Ceded Credit Risk [Line Items]
Percentage of accumulation of losses	100.00%
Quota share reinsurance reduced percentage	40.00%	50.00%
Catastrophe Reinsurance [Member]
Ceded Credit Risk [Line Items]
Excess of loss reinsured under an agreement	$ 750,000