Aggregate fair value of bond held.

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- Definition

Amortized cost of bond held.

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Number of securities classified as available for sale in unrealized loss position.

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Percentage of different kind of bond included in investment in special revenue bonds.

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Realized gain on investments.

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- Definition

Realized loss on investments.

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Reclassification adjustment out of accumulated other comprehensive income amortization of unrecognized loss.

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Threshold limit for investment held.

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 220
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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Amount before tax and reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities and unrealized holding gain (loss) related to transfers of securities into the available-for-sale classification and out of the held-to-maturity classification.

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

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Investments - Additional Information (Detail)		3 Months Ended		6 Months Ended		12 Months Ended
Investments - Additional Information (Detail)	Nov. 30, 2013 USD ($)	Jun. 30, 2018 USD ($) Securities	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) Securities	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Schedule of Investments [Line Items]
Net unrealized losses arising prior to reclassification date	$ 15,100,000
Amortization of unrealized losses recorded in accumulated other comprehensive (loss) income				$ 575,107	$ 604,812
Accumulated other comprehensive loss		$ (16,666,961)		(16,666,961)		$ (2,684,275)
Net realized gain on investment		$ 2,137,000	$ 1,130,000	$ 3,282,000	3,679,000
Donegal Financial Services Corporation [Member]
Schedule of Investments [Line Items]
Percentage of ownership interest		48.20%		48.20%
Obligations of States and Political Subdivisions [Member]
Schedule of Investments [Line Items]
Aggregate fair value of bond held		$ 172,200,000		$ 172,200,000		190,700,000
Amortized cost of bond held		166,500,000		166,500,000		181,400,000
Special Revenue Bonds [Member]
Schedule of Investments [Line Items]
Aggregate fair value of bond held		82,800,000		82,800,000		90,000,000
Amortized cost of bond held		79,500,000		$ 79,500,000		$ 84,700,000
Education Bonds [Member]
Schedule of Investments [Line Items]
Percentage of investments in special revenue bonds				53.00%		53.00%
Water and Sewer Utility Bonds [Member]
Schedule of Investments [Line Items]
Percentage of investments in special revenue bonds				27.00%		26.00%
Equity Securities [Member]
Schedule of Investments [Line Items]
Net realized gain on investment		2,125,000	1,085,000	$ 3,270,000	3,629,000
Net realized loss on investment				2,600,000
Fixed Maturities [Member]
Schedule of Investments [Line Items]
Net realized gain on investment		$ 12,000	$ 45,000	$ 12,000	$ 50,000
Number of fixed maturity securities classified as available for sale \| Securities		523		523
Accumulated Net Unrealized Investment Losses [Member]
Schedule of Investments [Line Items]
Accumulated other comprehensive loss		$ (9,300,000)		$ (9,300,000)		$ (9,800,000)
Minimum [Member]
Schedule of Investments [Line Items]
Percentage of which the company held security of any issuer		0.10%		0.10%		10.00%