Consolidated Statements of Income and Comprehensive Income - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues
Net premiums earned (includes affiliated reinsurance of $190,924,704, $184,656,732 and $175,024,905 - see note 3)	$ 702,514,755	$ 656,204,797	$ 605,640,728
Investment income, net of investment expenses	23,527,304	22,632,730	20,949,698
Installment payment fees	5,157,163	5,302,896	5,834,897
Lease income	500,455	670,865	750,287
Net realized investment gains	5,705,255	2,525,575	1,934,424
Equity in earnings of Donegal Financial Services Corporation	1,621,605	1,086,157	1,277,229
Total revenues	739,026,537	688,423,020	636,387,263
Expenses
Net losses and loss expenses (includes affiliated reinsurance of $114,865,113, $102,124,332 and $100,110,773 - see note 3)	487,268,054	423,315,903	398,366,874
Amortization of deferred policy acquisition costs	115,065,000	107,876,000	99,513,000
Other underwriting expenses	116,538,431	108,458,742	97,709,656
Policyholder dividends	5,014,624	4,373,377	3,862,606
Interest	1,593,437	1,657,647	1,111,441
Premium paid on purchase of treasury stock			5,780,000
Other	1,432,529	1,412,944	2,451,418
Total expenses	726,912,075	647,094,613	608,794,995
Income before income tax expense	12,114,462	41,328,407	27,592,268
Income tax expense (benefit)	4,998,362	10,527,270	6,602,235
Net income	7,116,100	30,801,137	20,990,033
Statements of Comprehensive Income
Net income	7,116,100	30,801,137	20,990,033
Unrealized gain (loss) on securities:
Unrealized holding gain (loss) arising during the period, net of income tax expense (benefit) of $1,964,385, ($746,518) and ($1,788,852)	3,811,151	(1,386,391)	(3,322,149)
Reclassification adjustment for gains included in net income, net of income tax of $1,939,787, $883,951 and $677,048	(3,765,468)	(1,641,624)	(1,257,376)
Other comprehensive income (loss)	45,683	(3,028,015)	(4,579,525)
Comprehensive income	$ 7,161,783	$ 27,773,122	$ 16,410,508
Class A Common Stock [Member]
Basic earnings per common share:
Common stock - Basic	$ 0.27	$ 1.19	$ 0.78
Diluted earnings per common share:
Common stock - Diluted	0.26	1.16	0.77
Class B Common Stock [Member]
Basic earnings per common share:
Common stock - Basic	0.22	1.06	0.69
Diluted earnings per common share:
Common stock - Diluted	$ 0.22	$ 1.06	$ 0.69