Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2011	Jun. 30, 2011	Mar. 01, 2012 Class A Shares	Mar. 01, 2012 Class B Shares
Entity Registrant Name	DONEGAL GROUP INC
Entity Central Index Key	0000800457
Document Type	10-K
Document Period End Date	Dec. 31, 2011
Amendment Flag	false
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float		$ 169,329,416
Entity Common Stock, Shares Outstanding			19,998,596	5,576,775