Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2022	May 02, 2022
Entity Listings [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Document Transition Report	false
Entity File Number	0-15341
Entity Registrant Name	Donegal Group Inc.
Entity Central Index Key	0000800457
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	23-2424711
Entity Address, Address Line One	1195 River Road
Entity Address, Address Line Two	P.O. Box 302
Entity Address, City or Town	Marietta
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	17547
City Area Code	717
Local Phone Number	426-1931
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Common Class A [Member]
Entity Listings [Line Items]
Title of 12(b) Security	Class A Common Stock, $.01 par value
Trading Symbol	DGICA
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		25,842,665
Common Class B [Member]
Entity Listings [Line Items]
Title of 12(b) Security	Class B Common Stock, $.01 par value
Trading Symbol	DGICB
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		5,576,775