Contingent consideration from sale of business.

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Minimum percentage of excess class A common stock dividend over class B dividend.

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No definition available.

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Percentage of share in results of pooled business owned by third party.

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No definition available.

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Percentage of share in results of pooled business subsidiary.

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Percentage of voting power owned by major shareholder.

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Shares received as consideration.

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Stock ownership percentage held by major shareholder.

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Stock ownership percentage owned by third party.

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- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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- Definition

Fair value portion of assets classified as held for sale.

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-SubTopic 10
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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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No definition available.

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Carrying amount as of the balance sheet date of dividends declared but not received.

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Amount of tax benefit from exercise of option under share-based payment arrangement.

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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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The difference between the carrying value and the sale price of equity securities, not separately or otherwise categorized as trading or available-for-sale. This element includes investments in which the entity holds a small ownership stake (generally, less than 20% of the shares outstanding) and cannot exert significant influence.

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No definition available.

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Date the operations of the entity commenced, in CCYY-MM-DD format.

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Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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

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The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

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Dividends received on equity and other investments during the current period.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Carrying amount as of the balance sheet date of known and estimated obligations associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, which are expected to be paid in the next twelve months or in the normal operating cycle if longer. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, relocating employees, and costs associated with an ongoing benefit arrangement, but excludes costs associated with the retirement of a long-lived asset.

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Summary of Significant Accounting Policies (Detail) - USD ($)		1 Months Ended		12 Months Ended
	Mar. 08, 2019	Jan. 31, 2019	Jul. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Operations commenced date				Aug. 26, 1986
Stock ownership percentage owned by third party				51.80%
Voting power percentage of outstanding common stock				71.00%
Tax benefit for tax deductions related to option exercises				$ 64,765	$ 25,938	$ 873,515
Minimum percentage of class A common stock declared dividend excess over class B dividend				10.00%
Premiums and losses related to certain products				63.50%	63.90%	64.30%
Atlantic States [Member]
Business Acquisition [Line Items]
Percentage of share in results of pooled business subsidiary				80.00%	80.00%
Donegal Mutual [Member]
Business Acquisition [Line Items]
Percentage of share in results of pooled business owned by third party				20.00%	20.00%
Premiums and losses related to certain products				100.00%
DFSC and North West [Member]
Business Acquisition [Line Items]
Consideration from sale of business	$ 20,500,000
Consideration from sale of business fair value at closing date	20,900,000
DFSC and North West [Member] \| Donegal Mutual Insurance Company [Member]
Business Acquisition [Line Items]
Consideration from sale of business	85,800,000
Proceeds from dividend	$ 29,200,000
Peninsula [Member]
Business Acquisition [Line Items]
Restructuring charges			$ 1,900,000
Payments for restructuring cost			$ 1,500,000	$ 260,000
Impairment charge of real estate					$ 1,100,000
Fair value of real asset held for sale					$ 1,200,000
Net proceeds from sale of branch		$ 1,200,000
Restructuring charges, accrual				130,000
Donegal Financial Services Corporation [Member]
Business Acquisition [Line Items]
Gain (Loss) on Sale of Equity Investments				$ 12,700,000
Donegal Financial Services Corporation [Member] \| DFSC and North West [Member]
Business Acquisition [Line Items]
Outstanding stock ownership percentage	48.20%
Dividend payment to be received	$ 14,100,000
Class A Common Stock [Member]
Business Acquisition [Line Items]
Stock ownership percentage held by major shareholder				43.00%
Class B Common Stock [Member]
Business Acquisition [Line Items]
Stock ownership percentage held by major shareholder				84.00%
Minimum percentage of class A common stock declared dividend excess over class B dividend				10.00%