v3.26.1
Document And Entity Information - shares
 6 Months Ended
Jun. 30, 2026
Jul. 31, 2026
Document Information Line Items    
Entity Central Index Key 0000800457  
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2026  
Document Fiscal Year Focus 2026  
Document Transition Report false  
Entity File Number 0-15341  
Entity Registrant Name Donegal Group Inc.  
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 false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Amendment Flag false  
Document Fiscal Period Focus Q2  
Current Fiscal Year End Date --12-31  
Common Class A [Member]    
Document Information 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   31,542,507
Common Class B [Member]    
Document Information 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